dermatology core diseases Flashcards
acanthosis
temporary thickening of the epidermis due to an increase in keratinocytes
may be caused by rubbing
acantholysis
keratinocytes separating from each other
eg pemphigus where the autoimmune process inactivates desmosomal structures within the epidermis so that the cells float free from each other
alopecia
loss of hair
scarring alopecia
loss of hair due to destruction of the follicles (hair cannot regrow as the follicles are destroyed)
atrophy
loss of volume
eg loss of dermal substance you see in sun damaged skin on the dorsum of the hand in elderly lady
atrophy secondary to a disease process such as Discoid lupus erythematous where the dermis is reduced in volume as a result of inflammatory processes
epidermal atrophy
much harder to detect as the epidermis is usually thin and many people use the term to describe different things
-means a reduction in the spindle cell layer, and a reduction in the rete ridges and dermal papillae
atrophy of the dermis
also may mean that the vascular component of the dermis is more visible to the eye
-because the loss of collagen means you are better able to see the normal vascular structure because there is less collagen blocking the transmission of incident light
papule
small <1cm solid elevated palpable lesion
nodule
a papule larger then >1cm
macule
small non-palpable area of colour change
flat focal
patches
larger macule
plaque
flat palpable lesion
vesicle
<0.5cm fluid filled sac
pustule
pus filled sac
blisters or bulla
collection of fluid in epidermis >0.5cm
due to either cell to cell or cell to basement membrane or basement membrane to dermis loss of attachment
weal
localised oedema
crust
refers to dry exudate
commonly seen in eczema and impetigo
diascopy
means pressing on the lesion with a glass
eg to check that it blanches on pressure
if it blanches you know the colour is due to blood in vessels
erythema
redness of skin due to an increase in intravascular blood
fissure
a narrow ulcer
common on hands in hand eczema
hyperkeratosis
refers to thickening of the stratum corneum so that there are more layers of corneocytes then there should be
parakeratosis
thickening of stratum corneum but with corneum cells that have nuclei (usually anuclei)
hyperplasia
same as acanthosis
lichenoid
typically if lesions are small papules that are flat topped and resemble lichen planus- then it is lichenoid
also used to describe exaggerated skin markings and thickening seen in lichenification
milium (plural milia)
small epidermoid cyst
seen in newborns, on face of adults and secondary to some diseases eg PCT porphyria cutanea tarda
necrobiosis
degeneration of collagen which is found within palisading granulomas
-necrobiosis lipoidica - rash most commonly seen on diabetics shins, and granuloma annulare
nikolsky sign
refers to the ability to induce a blister on apparently normal skin by applying simple frictional force across the skin
feature of pemphigus and TEN
oncholysis
distal lifting away of nail plate from nail bed
commonly seen in psoriasis or dermatophyte tinea nail infections
panniculitis
inflammation of subcutaneous fat
eg erythema nodosum
pompholyx
skin on palms and soles has a different organisation in terms of tethering of the epidermis and dermis, as the epidermis is much thicker
oedema due to spongiosis, more readily forms vesicles that are relatively robust to trauma
vesicular appearance in eczema at these sites is known as pompholyx
petechiae
non blanching mm petechiae
purpura
non blanching >petechiae
ecchymosis
bruise
palpable purpura is a sign of
vasculitits
scale
small piece of stratum corneum
sclerosis
refers to change in dermis when the tissue feels harder and stiffer than normal and may relate to increases in collagen production
spongiosis
intercellular oedema within the epidermis
one of the cardinal signs of eczema
telangiectasia
small visible blood vessels
ulcer
full thickness break in dermis and epidermis
erosion
superficial- epidermis
psoriasis other presentation
inflammatory polyarthropathy
increase CVD risk and metabolic
presentation psoriasis
scaly red plaques
extensor surfaces, nails and scalp
waxing and waning course
some itch but not as itchy as eczema
pathology of psoriasis
- Epidermal hyperproliferation- keratinocytes
2. inflammatory infiltrate
epidermal hyperproliferation in psoriasis
- epidermal differentiation is derranged in psorasis with hyperproliferation
- parakeratosis- retention on nulcei
- absence of granular layer
- acanthosis: thickening of epidermis
- time taken for epidermal differentiation is shortened-rushed through in an immature state
inflammation in psoriasis
oedema in the dermis
T cell rich inflammatory infiltrate in dermis
polymorphs in dermis and epidermis
capillaries in dermis are increased
munro microabscesses
epidermis polymorph collection in psoriasis
psoriasis causes
mostly unknown- and based on what drugs works for what
-highly heritable - genes involved in innate, adaptive immune system and skin barrier function and keratinocyte
-APC, T cells, HLA, TNF, IL
HLA cw6
HLA B27
Linkage disequilibrium
-MHC on chromosome 6
risk of developing psoriasis if one parent affected
risk if both
15%
40-50%
% psoriasis prevalence
2%
2 peaks of onset of psoriasis
type1= starts in later teen years. early adulthood and more linked to HLA groups
type 2- onset in 5th or 6th decade
Triggering factors for psoriasis
- often presents first time after a strep sore throat- immune system
- HIV can aggrevate
- certain drugs: lithium, betablockers, INF a and chloroquine
- receiving a bone marrow transplant
- obesity, smoking and alcohol
- psychogenic- stress
koebner phenomenon
in some situations injury or damage to the skin causes the development of a psoriatic plaque at the site of the insult
-usually lag of 2 weeks
eg sunburn, surgery, exathema, accupuncture
Types of psoriasis 7
stable plaque guttate erythrodermic pustular flexuaral or inverse palmoplantar nail
stable chronic plaque psoriasis features
- scaly red well demarcated plaque, mostly seen on extensor surfaces of elbow and knees
- can occur also on genitals and scalp
- usually red unless obscured by an excess of silvery scale seen in plaque psoriasis
- called stable as tends not too change week to week
- well defined
how can scale of stable plaque psoriasis be removed
with keratolytic agents eg salicylic acid
emolients
why does psoriasis look white
untreated plaque psoriasis looks white is because of the light refracted at the stratum corneum
- in psoriasis the sc is thickened and disorganised so contains more air so more light is reflected than usually so the skin looks white
- increase refractive index
Auschpitz sign
bleeding when scratch off the plaque
guttate psoriasis
characterised by several hundred small lesions, which often follow a strep sore throat by 2-3 weeks
- most common on the trunk
- often first episode of psoriasis an individual develops and can then go onto develop stable
- raindrops
- usually resolves as guttate 6 months later
erythrodermic psoriasis
most of the skin is affected looks less like psoraisis red all over erythroderma refers to any rash >90% can be difficult to diagnose on first episode as many causes of erythroderma medial emergency as can get hypothermia as skin feels hot, dehydration -need admitting to hospital -dehydration
causes of erythroderma
- psoriasis
- eczema
- iatrogenic
- cutaneous T cell lymphoma
pustular psoriasis
pustules present due to collections of polymprophs (munro micro-abscesses) in epidermis which become large enough so can see
if pustules are all over the body- generalised can become quite unwell
2 forms of pustular psoriasis
- palmoplantar pustular psoriasis– palms and soles mostly affected
- generalised pustular psoriasis
- can become very ill although pustules are sterile
- pyrexia, rigors, severe malaise
other states in which pustules in psoriasis can be seen 2- induced
- plaques that are continually treated with steroids may become pustular- steroid induced pustular
- patients with very acute psoriasis if treated with strong concentrations of dithranol or tar, may develop pustular psoriasis
flexual or inverse psoriasis
-some patients get psoriasis predominantly in flexures eg natal cleft, under boob, antecubital fossa
-red and shiny
generally lack the scale
-needs different treatment and can be harder to target with phototherapy
nail psoriasis 3 changes
- pitting of nail plate
- oncholysis- separation of distal nail bed
- oily spots/ salmon patches = yellowy brown
cause of nail pitting in psoriasis
parakeratosis in dorsal nail matrix
scalp psoriasis
Scalp is very commonly affected lesions are usually discrete and spread beyond the hair line on to the borders of the scalp scales usually adhere to the hair shafts very rarely alopecia may develop itch can be a big problem
palmoplantar psoriasis
some patients with psoriasis have chronic hyperkeratotic psoriasis without pustules that is often indistinguishable from chronic hand eczema
systemic aspects of psoriasis
- inflammatory seronegative arthropathy
-patients can present with psoriatic arthritis and develop psoraisis later on
more usually other way round
-cardiovascular- increase risk of MI, peripheral vascular disease and emboli more common
diagnosis of psoriasis
clinical diagnosis
- describe as discomfort, irritation or pain
- rarely itch
differential scalp psoriasis
sebhorreic dermatitis
solitary plaques of psoriasis differentials
bowen disease- intra epithelial carcinoma
eczema- chronic hand eczema
assessment score for psoraisis
PASI
psoriasis area severity index
management of psoriasis
- Avoid precipitants- smoking and alcohol?, treat HIV infections, drugs
- Active treatments in psoriasis
- Topical- creams and ointments
- UVR- UVB or PUVA
- Older systemic- methotrexate, ciclosporin
- newer eg biologics
bad drugs in psoriasis
lithium
chloroquine
beta blockers
antimalarials
which type of psoriasis is assoc. to smoking
palmoplantar pustular
Topical treatments for psoriasis
- easy and safe but less effective
1. emollients- bland with or without salicyclic acid - which breaks down desmosomes of the SC to make plaques less visible
- Topical corticosteroids: mainstay of management, reduce thickness of plaque and reduce some scaling
- vitamin D analogues: normalises epidermal differentiation and inhibits epidermal hyperproliferation, neutrophils
- vitamin D analogues plus steroids
SE of topical steroids
-local atrophy with telangiectasia
striae
systemic absorption
-rebound effect
older treatments psoriasis
anthralin- dithranol and tar
pro- inflammatory but show anti-psoriatic activity
-tar put on and then dressings and then UVB
-3 to 4 week inpatient
phototherapy two main treatments
UVB
PUVA
UVB therapy
-shorter of the two wavelengths
-accounts more for sunburn
2-3x a week for 10-15 weeks
narroband UVB mostly used 311-313
works best for small plaque psoriasis especially guttate
risks of UVB therapy
- sunburn
- long term increase in rate of non melanoma skin cancer
PUVA therapy
psoralen and UVA
- tablet taken and inert until activated by UVA
- or in bathwater
- only active in areas therefore that UVA can get to
- hence wear glasses to block= cataracts avoid
how does psoralen work
-when activated it
-inhibits proliferation of both keratinocytes and any inflammatory cells present in skin
also
-causes mutations if the cell manages to replicate
PUVA or UVB
-PUVA is more effective
but more toxic in terms of skin cancer risk of both non-melanoma (SCC) and melanoma
systemic agents for psoriasis
Methotrexate
ciclosporin
systemic retinoids
how does methotrexate work and SE
- folic acid antagonist - limits DNA synthesis
- acts on immune system in psoriasis
main SE
- hepatic fibrosis and cirrhosis
- bone marrow inhibition
- teratogenicity and mutagenic on sperm
- can affect response to live vaccines
- increase malignancy and infection risk
- nausea- so use IM
how long do men that want to have children have to stop methotrexate and wait
3 months
monitoring methotrexate
weekly FBC and LFT and UandE routine basis
then 3 months after 3 to 6 months
drugs/ disease that interfer with methotrexate
NSAID- increase toxicity in bone marrow
renal disease impairs its excretion
ciclosporin action and SE
calcineurin inhibitor blocks T cell activation
short term management 3-4 months
SE -nephrotoxicity hypertension increase in risk of some viral cancers eg EBV, HPV and non melanoma skin cancer -hypertrichosis -gingival hyperplasia -vaccination and infection
Retinoids action and SE
-vitamin A like actions act on nuclear receptors
= ACITRETIN
SE -teratogenicity -elevates triglycerides -pancreatitis CVD mortality -mucosal and cutaneous dryness -hair loss -MSK pain
how long do women after acitretin need to wait before conceiving children
and how long for other types of retinoids
3 yrs
5 weeks for isotreinoin alitretinoin
what is Isotretinoin used for
Acne
shorter half life
retinoid
what is alitreinoin used for
some hand eczema
5 weeks before pregnancy
Biologics for psoriasis
- Tumour necrosis factor inhibitor
2. block other cytokine pathways
TNF inhibitors psoriasis examples 3
-eg etanercept, infliximab, adalimumab
ustekinumab blocks
IL12 23
Ixekizumab blocks
IL17
Guselkumab blocks
IL23
Risks with TNF inhibitors
- TB
- reactivation of eg JC
other systemic agents in psoriasis
fumarates
mycophenolate
hydroxyurea
aprelimast- phosphodiesterase inhibitor
what serious infection is assoc. to severe psoriasis
undx HIV
what is acne
disorder of pilosebaceous unit- hair follicle and sebaceous gland
types of comedones
whiteheads= closed blackheads= open
charaterisation of acne
comedones, inflammatory papules, pustules and scars
some also get nodules forming with sinus formation and cysts (cavities lined with epithelium) and pseudocysts (inflammatory masses)
pathogenic factors of acne
- abnormal keratinisation of follicular epithelium - hyperkeratinisation
- increased sebum excretion
- infection with gram positive rod Propionibacterium acnes P. acnes
abnormal keratinisation of the infundibulum in acne
- earliest change in acne is formation of microcomedones
- instead of desquammation breaking up the keratinocytes-
in the follicle, the keratinocytes all stick together along with sebum so form a plug towards the top of the follicle
- as the plug gets larger it becomes more visible- evnetually it distends the follicle and ruptures and bursts causing an inflammatory response
- get closed comedones and later open comedones
what are open comedoens
Black heads
filled with dead cells and sebum
due to melanin makes it black
sebum in acne
- sebum is necessary but not sufficient for development of acne
how is sebum produced
-by cell death of sebocytes in sebaceous glands with release of lipid cell contents in the lumen of the follicle
evidence that sebum production is under androgen control
teenages
PCOS
body builders
prepubertal enuchs dont get acne as little sebum
what is p.acne
propionibacterium acne
- found in everyone skin
- numbers are greater in those with acne with heavy colonsiation of follicular epithelium
how does p. acne relate to acne
- P.acne uses sebum as a substrate and breaks down products into free fatty acids
- the more sebum the more p.acnes
- some fatty acids are powerfully chemotactic for polymorphonucleates and cause abnormalities of follicular keratinisations and sitimulates innate immune system
so p.acne stimualates the innate immune system
inflammatory process of acne
=finally ruptures due to increasing pressure and
-direct release of p.acne lipases, chemotactic factors and enzymes leads to comedone rupture which results in exudation of keratin, sebum, p.acnes and cellular and vellus hair material into the surrounding dermis
- this drives an inflammatory casacde with neutrophil infilitration and release of oxygen reactive species and lysosomal enzymes- t cell infiltrate
nodulocystic acne describes
patents that get multiple inflammatory nodules whether there are true cysts or not
scarring in acne
worse the inflammation the greater risk of scarring
-different people scar to a different degree
-
types of scars
- Ice pick scars= narrow and deep
- keloid scars= large unsightly scars also seen after surgery and trauma
- also can just be shallow irregularity of skin’s normal surface
- hyperpigmented areas also
why are blackheads black
due to melanin
genetics of acne
- higher in identical twins
- sebum excretion rates under some genetic control
diet and acne evidence
aka little evidence
not due to food or washing
main types of acne 9
- comedonal acne
- papulopustular acne
- acne fulminans
- acne conglobata
- acne ecxoriee- des junes filles
- infantile acne
- mechanical acne
- chloracne
- cosmetic acne
comedonal acne
simple acne where comedones predominate over the inflammatory lesions of papules and pustules
ie lots of blackheads/ white heads
papulopustular acne
inflammatory lesions and pustules are more evident than the comedones
-note comedones may not be easily visible but are still present- cant have acne without comedones
acne fulminans
severe variant of acne with abrupt onset of nodular suppurating (pus producing) lesions
often following a deterioration of pre-existing acne in teenage boys
lesions ulcerate and result in severe scarring
emergency management
systemic features of acne fulminans
-joint pains
-pyrexia
hepatosplenomegaly
osteolytic lesions
high ESR
leukocytosis
protineuria
anaemia
acne conglobata
refers to severe form of nodulocystic acne with multiple painful abscesses and scarring
possible extensive involvment of chest, face, back, arms, scalp and buttocks
- unlike acne fulminans there are no systemic manifestations
- may occur with acne inversa
acne excoriee de jeunes filles
clinical picture when the acne appears fairly minimal but the patient seems to squeeze, excoriate or pick to an excessive degree the individual lesions
often young women
infantile acne
few months to 1 year
reflects androgen activity seen in both sexes but more males
in males elevated LH leads to testicular andorgen production and, in both sexes raised DHEA produced by the adrenals may be the explanation
fades after one year and then re-starts with puberty
seen as comedones, pustules and scarring
mechanical acne
mechanical damage or frictional occlusion of the skin from headbands eg chin straps or even leaning on your hands excessively can lead to increased in number of comedones and worsening of acne
chloracne
severe type of comedonal acne- usually secondary to dioxin exposure either from military campaigns, industrial accidents
cosmetic acne
variety of chemicals, especially oils or tar derivatives or aromatic hydrocarbons induce comedone formation leading to acne
- many are found in cosmetics
- although most inducers no longer used- oils based still cause problems
post-adolescent acne
- acne may persist beyond the twenties well into middle age, especially in women
- areas around the jaw and mouth may be particularly affected
- pre-menstrual flares are common
Endocrine causes of acne 5
inx
- hyperandrogenism in women- change in voice, body build, androgenicalopecia and cliteromegaly
- A normal menstrual cycle is strong evidence against any systemic endocrine abnormality,
- PCOS
- CAH congenital adrenal hyperplasia
- androgen secreting tumours
- androgens in body builders
- evaluation should include testosterone, DHEAS and hydroxyprogesterone
- steroid production adrenal and ovarian
when to consider endocrine causes of acne
severe acne
age of onset in unusual- childhood or middle age
Management options for acne approach
- single topical retinoids or benzoyl peroxide
- topical combination therapy - BPO, retinoids, abx
- antibiotic oral or hormonal methods in females
- systemic retinoids
management targets for acne
- reverse the keratinisation defect
- reduce sebum production
- kill of bacteria- p.acne
Topical retinoids used in acne
how it works
eg Isotretinoin, tretinoin
- vitamin A activity
- topical or systemic
- work by normalising follicular keratinisation
- and reversing the excess adhesion of dead corneocytes in the follicle
- do not affect sebum production
SE of topical retinoids and dosing
- tend to promote a mild inflammatory reaction
- means that they produce a slight toxic or irritant reaction like a mild sunburn -erythema, dryness, scaling
- therefore use once a day or if inflamamtory response prominent then every other day
predominant comedonal acne best treatment
retinoids best agent to start with
Benzoyl peroixde BPO action on acne
works by reducing the levels of P.acne within the follicle
-reduction in bacteria then leads to a reduction in pro-inflammatory free fatty acids and inflammatory activation
SE of benzoyl peroxide and dosing
- tend to promote a mild inflammatory reaction
- means that they produce a slight toxic or irritant reaction like a mild sunburn -erythema, dryness, scaling
- therefore gradually increase them
what oral antibiotics are used in acne
tetracyclines eg doxycyline or erythromycin
how long does a patient need to be on an antibiotic to see it taking an effect against acne
2 months
using oral antibiotics for acne
-systemic antibiotics are used for 3-6 months but then withdrawn
but continue with topical retinoid or BPO
-may need to commence the antibiotic again but people argue increasingly for therapeutic holidays to minimise resistance
which antibiotic can be used in pregnancy for acne
erythromycin
when are tetracyclines contraindicated
<12 as deposits and stains teeth and in bone
pregnancy teratogenic teeth and bone effects
which topical antibiotics are used for acne
erythromycin, tetracyclines, clindamycin
topical abx are commonly used with topical BPO
when will topical antibiotics not be suitable
for extensive chest and back involvement
other topical agent option for acne
azelaic acid- possess antibacterial, anti inflamamtory, and anti-comedonal effects
hormonal method acne options
- combined pill mainstay
- co-cyprindiol- oestrogen and anti-androgen but not used as much and is a teratogen
-in females can be used instead of oral antibiotics
oestrogen and progesterone on acne
oestrogen decreases sebum
progesterone increases sebum
how combined pill affects acne
- contains some oestrogen which decreases sebum
- inhibits ovulation which reduces ovarian androgen production and thus reduce sebum production
which systemic retinoid is used for acne
systemic isotretinoin
how does systemic isotretinoin work
potently reduces sebum excretion
(rem topical retinoids do not reduce sebum excretion
-does this by inducing a temporary and reversible atrophy of the sebaceous glands
when are systemic retinoids used in acne
if no response to conventional treatment
acne that is causing severe acne
how long is systemic retinoids prescribed for
4 months
-can be a delay before any beneficial effect is seen
complications of systemic retinoids
- can precipitate acne fulminans when starting so may need to use steroids to dampen down immune response
- highly teratogenic- need 2 methods of contraception
what needs to be checked before starting isotretinoin
FBC
LIPIDS
LFT
pregnancy test
side effects of isotretinoin systemic
-interferes with lipogenesis not just in sebacous but also in other keratinocytes so also get
chelitis, dry eyes, dry nose, nose bleeds, dry skin and eczema
? depression and mood
what do people on systemic isotretinoin potetnially need to stop wearing
contact lenses
monitoring when on on systemic retinoids
- blood test at start and after one month
- pregnancy test monthly and five weeks after stopping isotretinoin
how long after isotretinoin are you not allowed to get pregnant
5 weeks
shorter half life then acitretin
other treatments for acne 3
- potent peels (alpha hydroxy acids)
- photodynamic therapy (blue light plus topical porphyrins)
- comedone extraction or electrocaytery of comedones
dont need to know anymore
scarring in acne treatment
-scaring is irreversible- although can become less obivious
RX
-dermabrasion
drug induced acne presentation
papulopustular eruption or folliculitis without comedones
drugs that cause drug induced acne
steroids
anti-epileptic medications
lithium
complication of use of tetracycline for acne
can develop a widespread gram negative folliculitis
-need to stop the tetracyclines
EGF receptor inhibitors complication
can cause a widespread acne like pustular eruption with no comedones
acne inversa pathology
- disease is centred around follicles and sebaceous glands like acne
- occlusion of the follicular infundibulum and rupture of the follicle is central to its pathogenesis
rupture of the follicle with dispersion of its contents into the surrounding dermis and secondary inflammation
-this leads to initially
where does acne inversa mostly affect
groin axillae perineum peri-anal
presentation of acne inversa
- foul smelling discharge comprising of blood pus and serous exudate
- pain
- malaise
complications of acne inversa
squamous cell carcinoma in chronic lesions
infection can contribute- not primary problem
diff dx of acne inversa
often misdiagnosed as bacterial abscess
who and when gets acne inversa
women and young adults
not before puberty
treatment of acne inversa
- psychological important to consider as devastating disease
- systemic antibiotics combinations
- systemic retinoids
- systemic anti androgens
- systemic steroids in flare ups
but response is usually poor and get recurrences
- surgical: laser or excision (can be curative)
- TNFalpha inhibitors can improve some patients
cardinal lesions of urticaria
weal -raised dermal oedema
angioedema can also commonly be seen with urticaria
weal vs angioedema
angioedema is oedema in the deep dermis or subcutis
how long does urticaria last for
<24 hours
what are urticarial dermatoses
-same morphology as urticaria but last longer than 24 hours eg urticarial vasculitis urticarial drug reactions pemphigoid
pathology of formation of a weal
-exogenous vasoactive compounds injected into skin -eg nettle sting- dont act on mast cells
or
-endogenous mediators which have same effect
from H1 or non H1 mediators but act on mast cells to produce this
which proteases are found in mast cells on the skin
tryptase
chymase
determines what stimuli they react too-why the lungs and skin might react to different stimuli
what do mast cells contain type 1
- mast cells contain a range of inflammatory mediators- mostly histamine but also prostaglandins, leukotrienes, cytokines, proteases and heparin
- these are grouped together in granules
- if the mast cells are activated they degranulate and these contents are released
triple response weal and why get each one
- initial erythema-erythema close to injection site
- larger flare of erythema- axon reflex in which stimulation of peripheral nerves is transmitted along sensory nerves and then back along other sensory nerves causing release of mediators leading to vasodilation= antidromic stimulation
- collection of dermal oedema: due to increased permeability of post capillary venules leading to a transient increase in local oedema
predominant symptom of urticaria
itch
type 1 hypersensitivity reaction pathology
and is all urticaria caused by this
IgE molecules are present in a sensitised individualthat binds to high affinity IgE receptors on mast cells
antigen causes crosslinking of IgE receptors leading to a signalling cascade of mast cell so get urticaria
-not all urticarial reactions are caused by this type 1 reaction though as some are non-immunologically mediated (dont need sensitisation) and others involve IgG or complement
main types of urticaria
- acute urticaria
- chronic symptomatic urticaria
- contact urticaria
- physical urticaria
- solar urticaria
- cold urticaria
- cholinergic urticaria
- aquagenic urticaria
main causes of angioedema without urticaria
ACEi induced angioedema
C1 esterase inhibitor deficiency
acute urticaria definition
Urticarial episode lasting <6 weeks
causes of acute urticaria
- NSAID
- recent infection
- foods especially shellfish
- aspirin
- insect bites
- antibiotics- penicillin
- dyes in radiology
inx of acute urticaria
-most dont need any inx beyond a detailed hx
-if severe reaction refer to dermatological allergy service for inx
includes
- IgE testing
-prick testing
-biopsy only if think it is vasculitis
length of time a weal lasts vs length of time urticaria lasts
-weals are the lesion of urticaria
-weals last only 24 hrs
-they come and go
-draw around a few weals and review patient next day
if weals are persisting >24 hours then consider an alternative dx such as vasculitis
hence urticaria itself can last a few weeks but weals dont
if weals persist >24 consider
vasculitis
treatment of acute urticaria
- remove precipitant eg stop drugs
- commence antihistamines non sedative- fexofenadine, cetrizine
- prednisolone short course
- anaphylaxis own management with adrenaline
if risk of anaphylaxis give epipen
chronic symptomatic urticaria definition
-urticaria lasting longer than 6 weeks
association of chronic symptomatic urticaria
-autoimmune disorders
thyroid, vitiligo, rheumatoid, pernicious anaemia
pathology of chronic symptomatic urticaria
most patients have IgG anti IgE antibodies
or IgE antibodies to the high affinity IgE receptor on mast cells
these autoantibodies cause activation and degranulation of mast cell
trigger for why this autoimmune process suddenly occurs is unknown
other cause of CSU
-dietary: low levels of aspirin, azo-dyes or penicillin in the diet
but really there are some patients where the cause is unknown
management of CSU
- exclude other causes
- non sedative anti-histamines
- 2nd line= trial a different non sedative anti-H
rarely immunosuppression may be used eg ciclosporin, steroids
-omalizumab anti IgE monoclonal biologic used if failed H1 blockade
aspirin CSU - management
give leukotriene antagonists
2 mechanisms of contact urticaria
- non-immunological contact urticaria
2. immunological contact urticaria
non immunological contact urticaria pathology and cause
-either due to toxic agents from plants or animals that cause mast cell degranulation or weals directly
eg jelly fish, antropod, fragrances, benzocaine, alcohol, benzoic acid
immunological contact urticaria pathology
- these are usually protein products that require prior sensitisation
- LATEX
- examples include animal amniotic fluid exposure in vets, latex in surgical gloves and almost any foodstuff in the right individual
physical urticarias pathology
- specific physical agents are able to precipitate urticaria in some individuals
- mechanism linking the physical agent to the activation of mast cells is usually unclear
-in some cases there is a circulating factor- IgE that can transmit the disease eg from transplant if serum given to another
dermographism
-development of a weal immediately under area of skin that has had pressure applied to it
delayed pressure urticaria and management
-onset several hours later
can be provoked on the hands by carrying shopping or by pressure from a chair on posterior thighs
-can give NSAIDs
solar urticaria pathology
-triggers
- patients develop widespread urticaria under exposure to UV radiation (or even visible light) over a period of 10-15 mins
- onset is usually sudden
- can follow a recent infection or new drug
- if over a large area can result in collapse due to generalised histamine release
cold urticaria
- urticaria due to cold stress
- patients can present with airway problems after eating ice cream or with generalised collapse if immerse themselves in cold water
-not always related to direct contact and can occur with cold wind blowing
cholinergic urticaria cause
provoked by exercise, emotional stress or heat exposure
results in many very small 1-2 mm itchy lesions
aquagenic urticaria
urticaria from water contact on the skin
angioedema definition
refers to deeper swelling involving the subcutis and submucosae seen in sites such as lips, eyes tongue and other body sites eg hands and face
management of urticaria with angioedema
manage as urticaria
management of angioedema without urticaria and 2 main causes
much more serious as dont primarily involve mast cells
- ACE inhibitor induced angioedema
- C1 ESTERASE inhibitor deficency
Ace inhibitor induced angioedema pathology
- abnormalities of kinin metabolism eg bradykinin are central to the production of angioedema
- ACEi may cause angioedema because the ACE normally breaks down kinins
- can present a yr or so after starting
- can rarely present with lifethreatning airway obstruction
C1 ESTERASE inhibitor deficiency pathology
- C1 esterase inhibitor acts so as to inhibit a range of proteases
- This action inhibits the production of bradykinin as need proteases for the production
- therefore deficiency of c1 esterase= increased bradykinin
presentation of c1 esterase inhibitor deficiency
- fhx of sudden death
- phx of RECURRENT EPISODES of angioedema lasting several days with abdo pain, diarrhoea, upper airway obstruction
NO URTICARIA
treatment of c1 esterase inhibitor deficiency
-treat episodes with either c1 esterase inhibitor or
subcut icatibant - bradykinin B2 receptor antagonist
anaphylaxis presentation and pathology
-urticaria is often a feature
but urticaria rarely progresses to anaphylaxis
-widespread mast cell degranulation causes- vasodilation, hypotension, bronchoconstriction and circulatory collapse
inx test for solar urticaria
monochromator
eczema same as dermatitis
commonest inflammatory skin disease
pathology of eczema cardinal features…
- intercellular epidermal oedema- spongiosis
- lymphoid infilitrate of the dermis and epidermis
as the disease becomes chronic get
- acanthosis- thickening of the viable epidermis
- hyperkeratosis= thickening of the stratum corneum
- the spongiosis can then become less apparent
clinical features of acute eczema
- red
- oedematous
- blisters- reflect underlying spongiosis
- erosions
- weeping skin can stick to clothing or bed sheets
clinical features of chronic eczema
- skin appears thick, rough and dry
- can be fissures- narrow ulcers
- with continued rubbing as a result of itch- lichenification - exaggeration of normal skin markings
lichenification appearance
exaggeration of normal skin markings -from itching
presentation of eczema
- can be either acute or chronic or both at the same time
- many times it is hard to know how to classify an individual lesion
- ITCH!!! and therefore scratch key
two main pathological processes of eczema
- immune system behaving abnormally
- skin barrier function is in someway compromised such that noxious agents penetrate the skin and worsen inflammation, or defects in the barrier allow foreign antigens to provoke an immune response
3 major eczema syndromes
- contact allergic dermatitis
- contact irritant dermatitis
- atopic dermatitis - most common
contact allergic deramtitis pathology
- a hapten or an antigen penetrates the skin barrier and is processed by a langerhans cell or other macrophage or APC cell in the skin
- this is presented to a T cell at the regional lymph node
-T cell memory for the particular antigen develops over 1-3 weeks and subsequent exposure of the individual to this antigen - anywhere on the skin’s surface- results in the clinical features of eczema in 24-96 hours
=type 4 hypersensitivity reaction- T cell mediated and delayed response
contact allergic deramtitis pathology
- a hapten or an antigen penetrates the skin barrier and is processed by a langerhans cell or other macrophage or APC cell in the skin
- this is presented to a T cell at the regional lymph node
-T cell memory for the particular antigen develops over 1-3 weeks and subsequent exposure of the individual to this antigen - anywhere on the skin’s surface- results in the clinical features of eczema in 24-96 hours
=type 4 hypersensitivity reaction- T cell mediated and delayed response
-skin barrier also plays a role to an extent as if you have a damaged skin barrier leads to greater antigen presentation so more likely to develop
example of contact allergic dermatitis
nickel sensitivity
20% of the population
at some point in their life when nickel placed on skin they became sensitive to it
initially get acute eczema response
- erythema and induration
- weeping and blister
- itch
but if reaction is prolonged then itching and subsequent scrathing leads to acanthosis and hyperkeratosis
why doesnt everyone have nickel sensitivity
some antigens like nickel only provoke a response in individuals who are genetically susceptible in terms of the way antigens are presented to the immune system
-depends genetically on their propensity to recognise antigens as foreign
-also reflects on society eg allergic dermatitis is rising in henna tattoos due to PPD antigenic dyes
ALSO eg increase in nickel sensitivity amongst men as there is less different in men and women wearing jewellery nowadays
clinical features of contact allergic eczema
- body site distibution eg glasses and watch strap, plaster
- temporal pattern- better when on holidays, worse at work
- occupational hx and hobbies eg cashier and nickel in coins get hand contact allergic
examples of contact allergic eczema
- bricklayers and dichromates in cement= hand
- nickel coins and cashier= hands
- rubber bandages
- medications topical
- preservatives or dye in tannin leather= shoes rash
- steroids
- aftershave and fragrances
- eye drops
inx for contact allergic dermatitis is
patch testing
applied to back and left for 24 hours then skin examined at 48-96 hrs after removal
-know what to avoid then
can get false positives or false negatives
contact irritant dermatitis pathology
-it is a localised inflammatory reaction that is not initiated by the antigen specific immune system but may involve the innate immune system in response to epidermal cytotoxic damage from a range of chemicals and other stimuli
examples of contact irritant dermatitis
- hand washing- breaks the barrier eg surgeon, kitchen work
- doubly incontinence
what makes something irritant? pathology of contact irritant dermatitis
if they are able to emulsify or disolve lipids this will damage and overwhelm the barrier so they can pass into the epidermis, dermis and damage keratinocytes
-this results in inflammation so get all the clinical and pathological hallmarks of eczema
eg soaps, detergents, alcohol wipes, acids from fruit
contact irritant dermatitis vs contact allergic
contact irritant
-no period of sensitisation -so can have a inflamamtory response on first time exposed, and not a delayed response
- dose response in contact irritant, greater the exposure to irritants the more the barrier will be damaged so greater degree of eczema
- everybody in the population is to some degree sensitive to irritants whereas- for allergic it is either you are or not
what determines susceptibility to irritant eczema?
-level of exposure to irritants eg gloves, hand cleaning
eg healthcare workers
-individual susceptibility
-biggest risk factor is hx of atopic dermatitis
latex allergy presentation
contact urticaria
type 1 reaction so immediate
(NOT eczema)
inx for contact irritant dermatitis
- depends
- can do patch testing if need to exclude contact allergic eczema
management of irritant dermatitis
- aim to minimise damage and treat what left
- minimise exposure to soaps, detergents and other noxious agents
- protecting hands with gloves in the cold and gloves for washing dishes
atopic dermatitis most common age and clinical course
- 2 to 4
- often improves later during childhood but not uncommonly recurs as facial eczema in adolescence or hand dermatitis in later adulthood
- in some patients severe atopic eczema is lifelong in others it clears only to return with a later relapse
three factors in the pathology of atopic dermatitis
- atopy, and the relation between IgE an altered immune system and atopic dermatitis
- the role of an abnormal barrier in the pathogenesis of atopic dermatitis
- the role of infection or infectious agents including the microbiome in atopic dermatitis
atopy definition 2
- those individuals who have a personal or fhx of a group of disorders we have labelled as atopic- hay fever, dermatitis, asthma
- individuals who have raised IgE antibodies and have a tendency to mount IgE responses to a range of common antigens eg house dust mites
what does a RAST test measure
allergen specific IgE antibodies in blood
how come IgE is raised in atopic eczema but it the rash of atopic eczema is not like urticaria another IgE response
positive Ige REPONSES ARE not directly causal of eczema but merely reflect an abnormal immune system
- so might be a useful diagnostic marker but are not the cause of the skin rash
- therefore removing the antigens from the environment of the patient will not be expected to improve the patient as the antigens are not causal
what type of reaction is hayfever
type 1 hypersensitivity reaction
do you have to have other features of atopy to have atopic eczema
no you can just have the cutaneous features of IgE atopic eczema but not the atopic (based on hx, fhx, ige levels or prick testing)
what protein is implemented in the abnormal barrier seen in patients with atopic dermatitis
- filaggrin-filament aggregating proteins
- patients with atopic eczema have an inherited skin barrier abnormality
- a filaggrin deficient cornified envelope leads to a defective cytoskeletal barrier with abnormalities in lamellar bodies and the normal stratum corneum lipid barrier
- these mutations occur in 10% of the population and those with a mutation in one allele are three to five times more likely to develop atopic eczema
-you can develop atopic eczema without a filaggrin mutation -but probably means their is a mutation in another gene not known about
which bacteria is found on the skin of patients with atopic eczema and why
- staph aureus
- some products of the innate immune system such as defensins produced by keratinocytes are decreased in atopic eczema
- which can contribute to an inability to deal with staph aureus on the skin -which in turn exerts an effect on the cutnaeous immune system
- efficacy about treatments targeting this arent full proof
genetics in atopic dermatitis
-strongly familial due to inheritance of barrier dysfunction and inherited nature of atopy
chance of having eczema if one or both parents have it
20%
50% for both
secular changes and atopic dermatitis
-relates to hygiene hypothesis causing an increase in eczema in the last 40 yrs
a baby develops an itchy rash with scaling on the face and scalp at 6-12 months of age
the rash spreads involving many of the extensor surfaces
itch is a prominent feature with the child scratching and rubbing the affected areas. sleep disturbance can be prominent.
as the child grows older the rash appears worse in the flexures behind the knees and elbows with skin feeling weepy and sticking to the pyjamas
by contrast much of the rest of skin feels rough and dry
soap and detergents make it worse
in the teenage years the rash subsides but facial appears intermittently and the child also develops hayfever and asthma
atopic dermatitis hx
diagnosis of atopic eczema
- clinical features and hx
-not prick testing or IgE measures
(may be undertaken for assoc. type 1 clinical syndromes such as urticaria or food allergy)
clinical feautures of atopic eczema
- erythema with little scale initially through to erythema with a lot of scaling -usually poorly demarcated
- itchy!!-excoriations, scratching
- “wet” oozy skin due to spongiosis and blisters in acute state
- lichenification: in chronic form plaques of skin may be markedly thickened and rough, with an exaggeration of the normal skin folds. response to scratching
- nodular prurigo is another response to scratching in which you get focal nodules in response
-the skin all over may feel and look dry and feel like sandpaper
- pityriasis alba
- dennie morgan folds
- chellitis
- recurrent conjunctivitis
-focal lesions measuring mm- papular eczema rather than patches or plaques measuring cm can be seen
what is cradle cap
atopic dermatitis in infants
yellow crust and scale on the scalp
what is pityriasis alba
white slightly scaly patches on the face and trunk of children that may be confused with vitiligo
what is dennie morgan folds
double fold of skin of the lower eye lid secondary to rubbing
increased peri-orbital pigmentation is also common and markedly symptomatic
peri-ocular eczema
cheilitis is
sometimes seen
consequent of licking of lips leads to an irritant dermatitis around the mouth
why can patients with atopic eczema get conjunctivitis
due to rubbing of the eyes
atopic dermatitis ocular assoc.
recurrent conjunctivitis
cataracts
risk of applying excessive topical steroids to the eye
can be absorbed into the ocular mucosae
physical signs of palms and sole eczema
can be different
- frank blisters
- lots and lots of very small vesicles
- pomphyolyx eczema ie small blisters/ vesicles eczema seen first on the side of fingers -
- can be marked hyperkeratosis and can mimic psoriasis so need a biopsy
- hyperlinear palms- in filaggrin mutations
secondary infections eczema
- can occur in all types of eczema
- particularly with staphylococci
- but also Herpes simplex which is a major concern and carries a risk of death = eczema herpeticum
appearance of eczema herpeticum and risk in children
many ulcers that appear monomorphic and may be punched out
-herpes encephalitis
diff dx of eczema
- fungal?
- impetigo?
- scabies?
- contact allergic eczema?
- ichythosis- also filaggrin mutation and get abscence of inflammation and presence of lots of scale
IF there are no signs of scratching reconsider your dx of atopic eczema
precipitants of eczema 7
- low ambient humidity- warm temp makes disease worse as skin dries and cracks and scale occurs and scratch increases
- wool- wool is an irritant especially in the presence of sweating- use cotton instead
- psychological stress- tends to increase scratching and make disease worse
- exposure to water- paradoxically dries out the skin -soap and detergent exposure also worsens disease-and avoid hot and long baths
- initial localised staph aureus infection of the skin can lead to generalised worsening of the disease
- atopics have an increased in rate of type 1 reactions to foodstuffs-more of a problem in children in which urticaria may develop after ingesting foods leading to increased itching and scratching and resulting in worsening eczema
Treatment of atopic dermatitis
- avoidance and prevention
- emoilients, antiseptics and bandaging
- topical steroids or topical calcineurin inhibitors
- new topical agents eg crisaborole - not yet licensed
- sedative antihistamines not to target histamine but sedation reduces itch
- phototherapy
- systemic immunosuppressive -prednisolone, aza, ciclosporin, methotrexate
aim of treating atopic dermatitis
- difficult to balance- psycho-social issues
- big issue is sleep disturbance
- physical signs vary over time
- aim to not banish disease but reduce extent of it
prognosis of atopic eczema
- uncomplicated eczema does not result in scarring or permanent damage to the skin
- many children with atopic dermatitis do grow out of it -majority grow out
- but more severe childhood disease the greater the chance that the disease will persist into adulthood
avoidance and prevention advice in atopic dermatitis
- avoid soap and detergents and other agents that damage the barrier and make it worse
- avoid wool
- keep cool - bedrooms and cotton bed sheets
- dont soak in a bath and not too hot
- avoiding antigens- DOES NOT CAUSE THE RASH OF ECZEMA- but if the skin is broken then exposure to a type 1 antigen can provoke a type 1 response- ie urticaria which results in itching and will therefore worsen the eczema
- same for food allergies and type 1 response - if a child has food allergies then they can get urticaria which causes scratching and worsening of atopic dermatitis
-practically dont need to banish pets or super-clean the house
emoilients for dermatitis
-first line
rehydrate and restore skin barrier
-range
aqueous based to greasier ones
complication of emoilients in dermatitis
- sometimes can get a stinging sensation immediately when applied
- should switch emoilients
antiseptics use for dermatitis examples and use in atopic dermatitis
- potassium permanganate or chlorhexidine can be added to bathwater
- tend to help with acute atopic dermatitis as act as drying agents-
-such antiseptics are also used- usually with systemic antibiotics when the skin is obviously infected as is the case when there is widespread crusting and numerous pustules
acute eczema clinical features
- wet due to spongiotic oedema
- breaking open
- small blisters or large
- red and oedematous without much scale
chronic eczema clinical featurs
if a patch of dermatitis appears dry and thickened with or without lichenification it is referred to as chronic eczema
-can have both acute and chronic at the same time a
acute eczema treatment
- avoid ointments
- use creams instead - water based ones
- topical antispetics are also useful drying agents
chronic eczema main principles of treatment-
dried out skin
so use ointments rather than creams
bandaging in eczema action
- protects skin from damage due to scratching
- reduce sensation of itch by minimising effects of external stimuli on the skin
- promotes healing of broken skin
main toxicities of steroids topical
- atrophy of skin- thinning, telangiectasia, striae and easy bruising
- also get systemic absorption leading to cushing’s- greatest in children and flexural areas
principles of prescribing topical steroids for eczema
-dont combine with antibiotics- sensitisation
-antiseptics can be used in combination
weak
topical calcineurin inhibitors eg tacrolimus for eczema situation and method of action
- useful on the face or skin creases
- alternative to topical steroids-less potent but dont cause skin atrophy
- worry about risk of skin cancer and herpetic infection
-suppress t cell activation and reduce cytokine inflammation
crisaborole action
phosphodiesterase 4 inhibitors
how are antihistamines effective for eczema
- itch of all types of eczema is not mediated by histamines
- so dont use topical antihistamines
- can use systemic sedative antihistamines- which work by sedation of awareness of itch
phototherapy for dermatitis
both UVB and PUVA have been used
- UVB is safer but less effective
- also more variable response to UVB in dermatitis- can get worse
systemic immunosuppressants for eczema 6 and efficacy and how long used for and what for
prednisolone- only short courses and not children
ciclosporin-highly efficacous but short courses
methotrexate-less efficacous
aza-takes a while to kick in and measure TPMT
retinoids- alitretinoin for hand eczema
dupilumab
duplimumab action
-blocks IL4 and IL13 receptors
SC every 2 weeks
moderate or severe disease
varicose eczema presentation and management
- legs of those with venous incompetence
- target the primary problem of the venous insufficiency
- however eg use of support stockings with rubber and cream can increase risk of contact allergic dermatitis
discoid eczema presentation and treatment
- well demarcated annular areas , venous oedema, venous flare, varicose veins
- middle aged adults
- treat with steroids
sebhorreic eczema cause and presentation
yeast pityrosporum
treat the infection
-also called cradle cap, neonate and early life then a teen peak with grease
-scaly and fine
contact allergic dermatitis main pointers in hx
- body site distribution eg plaster
- temporal pattern
- occupation and hx
bullous disorders 3 main ones
- immunobullous- pemphigoid, pemphigus and dermatitis herpetiformis
- erythema multiforme, stevens johnson and toxic epidermal necrolysis TEN
- staph scalded skin syndrome SSSS- young children
pathology of forming blisters
- blisters reflect the accumulation of extracellular fluid either within the epidermis, between the epidermis and basement membrane or between the dermis and the basement membrane
main cause of blister formation
-due to loss of adhesions between keratinocytes or between the keratinocytes and the basemement membrane or the dermis and the basement membrane
what is epidermolysis bullosa
mutations in keratins
- inherited disorder
- blistering
- often present at birth or soon after birth
- some produce severe scarring
pathology of pemphigus
-auto-antibodies to desmosomes-
2 types of pemphigus and location
- pemphigus foliaceous- IgG antibodies attack desmoglein 1- superficial blisters
- pempgius vulgaris- attack is on desmoglein 3 +/- desmoglein 1 - deeper skin
desmoglein 1 and 3 compensation in the skin
- Dsg 1 is present throughout the skin but expressed most highly in superficial layers
- Dsg 3 is expressed in the skin in the basal and suprabasal layers but NOT in superficial
antibodies to desmoglein 3 only
mucosa and skin expression
if antibodies to only Dsg3 then Dsg 1 can compensate so there is little or no blistering
but will get mucosal blisters - mucosal dominant pempigus vulgaris
antibodies to both dsg 1 and 3
mucosa and skin
then there is no compensation so get pemphigus vulgaris
also get mucosal blisters and extensive skin disease
-mucocutaneous pemphigus vulgaris
antibodies to dsg 1 only
skin and mucosa presentation
get pemphigus foliaceous -superficial blisters
in mucosa there will be no mucosa phenotype as little Dsg 1 expression anyway
so no mucosal phenotype if foliaceous
mucosa expression of desmogleins
-in the mucosae there is very little Dsg 1 expression and Dsg 3 is expressed in all layers
who are more likely to get pempgius 2
middle age
certain jewish populations
what is fogo selvagem
- rare variant of pemphigus foliaceous
- burning pain
- brazil carried by anthropods
clinical features of pemphigus
- blisters- but break easily so can just have erosions and crusting
- mucosal involvement only in pemphigus vulgaris which can involve the eyes mouth, pharynx, larynx oeseophagus as well as genitalia
- Nikolsky sign
where is pemphigus foliaceous rash often found
face chest and upper back
what is pemphigus often misdiagnosed as
eczema as blisters often pop and lead crusting and erosions
what is the nikolsky sign
rub apparently normal skin it causes a blister to develop or if you press a blister it spreads outwards
diagnosis of pemphigus 3
- biopsy- shows acanthloysis (separation of the keratinocytes from each other)
- immunofluoresence- confirms IgG intercellular staining within the epidermis - autoantibodies
- indirect IF against circulating antibodies are usually present and correlate to some extent with disease activity
treatment of pemphigus
- large dose of steroids
- immunosuppressive sparing agents- azathioprine, mycophenolate are frequently used
- IV immunoglobulin Anti CD20 antibodies or cyclophosphamide
-drug treatment may be tapered off as circualting antibodies decline
pemphigoid pathology
-antibodies to hemidesmosomes (anchor keratinocytes to the basement membrane
which is more common pemphigus or pemphigoid
pemphigoid
clinical features of pemphigoid
- itchy urticariated lesions which may precede the onset of blisters for several months
- early rash can be dx as eczema
age of onset pemphigoid
any age
usually >60
pemphigus blisters vs pemphigoid
pemphigoid blisters are larger and more robust
only 20% mucosal disease
what is pemiphoid gestationis
pemphigoid seen in pregnancy
result of aberrant expression of paternal MHC on placenta, and a maternal antibody response to placenta basement proteins that cross react with the target hemidesmosomal proteins in the skin
diagnosis of pemphigoid
- biopsies show an eosinophil rich inflammatory infiltrate and sub-epidermal blisters
- with IgG immunofluoresence staining along the basemement membrane
TREATMENT of pemphigoid and prognosis
- topical steroids
- systemic steroids
- azathioprine as steroid sparing
- IV immunoglobulins, anti CD20 antibodies or cyclophosphamide.
- chronic disease so aim to use the smallest dose compatible with clinical resolution
- remission will eventually occur in most patients
dermatitis herpetiformis pathology
- dermatitis herpetiformis is a skin immunobullous disorder that is assoc. with GI gluten sensitivity
- most have evidence of this assoc. gluten sensitive enteropathy but only a minority have clinical GI symptoms
- gliaden found in gluten
- gliaden is absorbed and is a substrate for a transglutaminase enzyme in the GI tract
- some people with HLA groups- see this complex as foreign and T cells produce IgA antibodies to transglutaminase
- transglutaminase is also found in the skin and helps to create the cornified envelope
- IgA antibodies to transglutaminase bind there and causes immune complex deposition leading to recruitment of neutrophils and release of proteases
- causes a neutrophil abscess
clinical features of dermatitis herpetiformis
- intense itch that is described as burning
- small clusters of vesicles are present most commonly on wrist, extensor aspects of elbow and knees and sacrum and buttocks
- no mucosal involvement
- often intense itch means cant always see intact vesicles
diagnosis of dermatitis herpetiformis
-need biopsy- see small polymorph abscess in upper dermis
-immunfluorescence shows IgA deposition in dermal papillae
-80% will have anti endomysial antibodies
-
treatment of dermatitis herpetiformis
- gluten free diet
- dapsone
side effect of dapsone
agranulocytosis
haemolytic anaemia
need close monitoring
pemphigus immunofluoresence
-inter cellular staining
meshwork
acantholysis
separation of keratinocytes
age distribution pem goid and phigus
-pemphigoid >60
pemphigus >50
4 main blistering syndromes (not autoimmune ones)
- Erythema multiforme
- toxic epidermal necrolysis TEN
- stevens johnson syndrome
- Staph scalded skin syndrome ssss
what is SSSS
scalded skin shock syndrome
-due to staph toxin
looks like TEN
if you kill staph it goes away
what is erythema multiforme
- usually a mild illness affecting the distal skin surfaces of young people possibly with mild mucosal involvement
- classical clinical appearance is the “target lesion”
- virtually all cases are an immunological response to an earlier infection eg herpes simplex
what is TEN
toxic epidermal necrolysis
- catastrophic response to a drug
drug metabolism and immunological reaction
-results in a large sheet of epidermal keratinocyte cell death resembling a widespread burn with mucosal involvement
what is steven johnson syndrome
-milder form of TEN
overalll disease is milder but the mucosal disease predominates
erythema multiforme clinical features
- target lesion- annular lesion with a red or dusky cyanotic centre and a bright erythematous outer ring separated by a slightly paler zone
- haemorrhage or blistering can occur in the central lesion
- lesion is initially macular and then can become raised and into bulla
- lesions subside over a few weeks without any scarring
-mucosal lips eyes and genitals
where is the target lesion most commonly found
-extremities acral hands and soles face elbows knees
who is erythema multiforme more common in
young people <40
males more
cause of erythema multiforme
- main cause of EM are infections commonly herpes simplex, or mycoplasma
- other infections can cause it too
- rarely drugs might precipitate EM
18 year old male with herpes simplex then a week to two weeks later develops strange lesions on his palms which then spread to other body sites and the mucosae
these lesions appeared over the course of a day and at three days are now with bullae and haemorrhages in some cases
erythema multiforme
types of erythema multiforme
erythema major- mucosal disease more severe and fever and joint pains are a feature
erythema minor: mucosal disease is milder and no systemic features
pathology of EM and diagnosis
- dx is usually clinically
- can do biopsy if needed: shows widespread epidermal cell death (keratinocyte death) with some dermal inflammation
treatment of erythema multiforme
- if patients develop repeated episodes it is almost certainly due to recurrent herpes simplex and can give antivirals
- acute phase no treatment beyond basic skin care such as antiseptics
- if clinically symptomatic then topical steroids can be used
- IV fluids for severe mucosal involvement
complication of erythema multiforme
-eye involvement with or without symptoms can warrant an opthalmology consult because of the potential for late scarring
differential of target lesion
erythema multiforme
urticaria
toxic measles like drug rash
toxic epidermal necrolysis who is it more common in 5
more common in elderly but can occur in children
- genetics HLA
- immunosuppressed
- people who are slow acetylators ie drug metabolises slow
what causes TEN and when does it tend to appear
- potentially fatal skin and mucosal adverse drug reaction
- tends to appear 7 to 28 days after commencement of a drug
- genetics HLA
clinical presentation of TEN
- sudden onset of diffuse erythema with sheets of skin undergoing necrosis
- wrinkling or blisters within those sheets can be seen
- epidermis lifts off the basement membrane due to widespread keratinocyte death
- Nikolsky positive
- pyrexia, malaise, dysuria, sore eyes can precede onset of rash
- mucosal involvement -lups, eyes, genitals , mouth
- extrememly painful!
- macular deep red/ blue areas can be seen
where is TEN worse
often Trunk
pathology of TEN
- full thickness epidermal death due to Fas mediated cell apoptosis
- epidermis lifts off the basement membrane
management of TEN
- medical EMERGENCY
- stop relevant drugs ASAP -slow half lives of drug/ metabolites can be problematic
- HDU/ ITU
- fluid balance, analgesia
- controlled pressure thermoregulated bed
- aluminium sheet
- skilled derma nursing
- opthamology for eye
drugs that are more likely to cause TEN
allopurinol
carbamazepine
sulphonamide
main cause of death from TEN
infection
hypercatabolic state
prognosis scoring system for TEN
-SCORTEN based on
>5 death in 90% of cases
-age, extent, HR, glucose, bicarb levels …
TEN mortality
40%
what is steven johnson syndrome
best viewed as a milder form of TEN with more mucosal involvement
involves <10% of the body
mortality and morbidity is also lower
SSSS pathology
certain subtypes of staph produce a toxin which is a serum protease that cleaves desmoglein 1 (same as pemphigus foliaceous)- so targets superficially
-in SSSS it is circulating so affects all over rather than in impetigo where it will affect a certain area
clinical features of SSSS and who gets it
clinical features timeline
- superficial skin
- no mucosal involvement (unlike TEN)
- mostly children <5 but can be seen in adults with immunosuppression, renal failure
- site of the staph infection is not usually the skin but nasopharynx or conjunctivae
- onset is with a scarlet fever like rash, often around the mouth and nappy area, with perioral crusting and furrowing
- erythema appears on the face, with or without oedema and then generalises
- pyrexial but looks well initially
- intense pain and separation of skin in sheets on red base
- over 48 hrs widespread flaccid blisters develop and nikolsky sign can be positive
diagnosis of SSSS
clinical suspicion
superficial biopsy can differentiate SSSS from TEN
culture swab from throat and eyes (NOT SKIN)
management of SSSS
IV flucoxacillin, vancomycin- as advised by mico
difference between ssss and TEN 3
SSSS
- split at granular layer
- children
- no mucosal
TEN
- split full thickness epidermal- fas
- older people
- mucosal
nikolsky sign
The Nikolsky sign is dislodgement of intact superficial epidermis by a shearing force, indicating a plane of cleavage in the skin at the dermal-epidermal junction.
vasculitis pathogenesis
-most common mechanism is deposition of immune complexes in vessels walls leading to complement activation of neutrophils with resulting damage to the vessel walls and an inflammatory reaction around the vessel
ANCA positive vasculitis pathology
-IgG antineutrophil cytoplasmic antibodies react with intracellular antigens on neutrophils and also activate neutrophils leading to an antibody dependent cellular cytotoxicity on endothelial walls
main triggers of vasculitis
- infection
- drugs
- an underlying systemic inflammatory process eg SLE, RA, ANCA and positive vasculitis
main types of vasculitis
-leucocytoplastic septic sweet's syndrome erythema nodosum pyoderma gangrenosum
leucocytoplastic vasculitis pathology
- most common type of cutaneous vasculitis in derm
- immune complex deposition leads to inflammation of the post-capillary venules
- vessel wall is damaged with fibrin deposition and neutrophils move into the skin
biopsy signs leucocytoplastic v
-neutrophil infiltrates
-later undergo leucocytoclasis with nuclear dust - remnant of polymorph nuclei
nuclear dust-
clinical features of leucocytoplastic V
- palpable purpura (non blanching)
- most common on the legs
- early in the course can just appear as erythema
- can be blistered or even pustular lesions
main causes or assoc. of leucocyctoplastic v 5
- infections eg Hep ABC strep or mycobacterium
- drugs
- malignancies
- small vessel vasculitis- wegner, churg strauss, polyarteritis nodosa
- systemic disease
what drugs are assoc. to LV 3
-beta blockers
penicillins
thiazide diuretics
what malignancies are assoc. to LV 3
CLL
lymphoma
myeloma
what systemic diseases are assoc. to LV
-IBD
SLE
bechet
diagnosis LV
clinical
biopsy can be done
management of LV
- legs usually affected so
- bed rest and elevate legs and compression bandaging
- topical steroids
- systemic steroids
- dapsone
BUT BEFORE PRESCRIBING STEROIDS MAKE SURE IT IS NOT SEPTIC VASCULITIS
prognosis of LV
-most resolve 2-6 weeks
in a minority it is chronic with relapses
what type of vasculitis is henoch schonlein purpura
leucocystoplastic vasculitis
septic vasculitis clinical features
- lesion looks similar to leucocystoplastic vasculitis- but more often pustular with necrosis and blistering
- often more unwell but may not be initially
- can be pyrexial
- signs of other tissue damage
main causes of septic vasculitis 2
and immunosuppressed 3
- gonococcus
-sub acute bacterial endocarditis
also
-staph, meningococci, fungi eg candida (immunosuppressed)
management of septic vasculitis
- FIND AND TREAT INFECTION
- circulating micro-organisms
- and can be immune complexes and thrombi in post-capillary venules
other signs of sub acute bacterial endocarditis
osler nodes: lesions on tips of fingers and thenar and hypotheniar eminences
janeway spots: superficial haemorrhages on palms
pyoderma gangrenosum clinical feature
-often starts as a very small and painful lesion commonly on the legs (looks like an insect bite)
-this then becomes pustular and breaks down
-ulcer with red/purple edges
-ulcer grows in size and get pain
-can expose deep structures such as tendon and muscles
-heals leaving cribiform scarring
can be systemically unwell
what is pathergy
-development of ULCERS eg pyoderma gangrenosum at sites of fairly minor trauma eg venous line insertion
diseases assoc. to pyoderma g
- IBD
- ra
- ank spond
- myeloma
- dm
- chronic active hepatitis
- primary biliary cirrhosis
pathology of pyoderma g
- large neutrophilic infiltrate with fibrin deposition in vessels and leucocutoclasis
- can see evidence of vasculitis
what is leucocytoclasis
vascular damage due to nuclear debris from infiltrating neutrophils
dx of pyoderma g
clinical dx
differential pyoderma g
- ulceration eg arterial and venous pathology
- tumours
treatment pyoderma g
systemic steroids
treat underlying assoc. disease
topical steroids
other immunosuppressive
Sweet’s syndrome other name
acute febrile neutrophilic dermatosis
clinical features of sweet’s syndrome
- patients present acutely with plaques or nodules that to the unintiated often look blistered due to the amount of oedema
- lesions can be pustular
- can be assoc. arthralgia and pyrexia
pathology of sweet’s syndrome
- can present as pathergy
- oedema in high dermis, prominent neutrophil infiltrates and possibly vasculitis
diagnosis of sweet’s
-mostly clinical
diff dx of sweet’s
- pyoderma g
- leucocytoplastic v
- erythema nodosum
triggers of sweet’s syndrome
- AML
- infections
- malignancies
- gammopathies
- drugs
- autoimmune disorders
treatment of sweet’s syndrome
-prednisolone given over a few weeks
erythema nodosum clinical features
- presents as a self-limiting panniculitis (inflammation of fat)
- painful, red raised or indurated lesions mostly on lower legs in young adults
- no ulceration and epidermis is intact
- more common females
- can be malaise, pyrexia arthralgia
triggers/ asssoc. of erythema nodosum 7
drugs bacteria eg strep or mycobacterial sarcoidosis brucellosis malignancies eg lymphoma leukaemia IBD behcet
2 drugs linked to erythema nodosum
-oral contraceptives
penicillins
diagnosis and management of erythema nodosum
- over 50% patients no explanation- infection?
- NSAID
- compression stockings
- systemic steroids
prongosis erythema nodosum
most patients only have one episode
diff dx of erythema nodosum
genuine nodular vasculitis- rare
-can present as a similar picture -TB
alpha 1 antitrypsin deficiency
fat necrosis
photosensitivity skin disorders
are group of disorders that are provoked by either UVR or visible light
main photosensitivity skin disorders 5
- polymorphic light eruption PLE
- solar urticaria
- lupus erythematous
- two types of porphyria
- phototoxicity and drug induced photosensitivity
body site distribution of photosensitive disorders
- areas of maximal sun exposure are the tops of the ears, cheeks, nose, scalp vertex if bald, face and dorsum of hands
- depends also on clothing patient wears eg V neck shirts, short sleeves
BUT NOT ALL FIT INTO JUST AFFECTING SUN EXPOSED SITES
polymophric light eruption distriubtion
-tends to spare the face and the back of the hands
Lupus erythematous rash distribution
-can appear worse on sites such as the shoulders, upper back and chest
what does diagnostic phototesting involve
monochromator
-applies different wavelengths to skin to see if there is a response and at which wavelength
problems with diagnostic phototesting 3
- LE will take a few weeks to respond so will be missed
- some disorders need larger areas of exposure of skin to get a response
- test lamps might not mimic natural exposure compleletly so false negatives can occur
what blocks UVB
- glass
- sunscreen
how common is polymorphic light eruption
commonest photosensitive disorder
10-20% of the population at some time in their life
what is polymophic light eruption often mislabelled as
-sun screen allergy
heat rash
prickly heat
-so doesnt come to medical attention but for most it is mild and self -limiting
clinical features of polymorphic light eruption
- called polymorphic as appears different in different people
- itching and erythema several hours to days after sun exposure on sun exposed sites
- symmetrical rash
- papules, plaques, vesicles which may become raised with indvidual lesions that look like urticaria or large erythematous plaques - but persist for longer than urticaria
- rash may last several days or longer in severe cases
- can be bullours or haemorrhagic even
where does polymorphic light eruption commonly affect
upper arms
neck
sides of face
shoulder
when is PLE most common
spring- spring eruption and if exposure is continued further occurrences tend to diminish
till the following year the rash then usually returns
diagnosis of PLE
- clinical hx and sometimes exam
- diagnostic phototesting can be used but a negative result doesnt rule it out
diff dx of PLE and how to differentiate
- solar urticaria- rash comes on within 5-10 mins of exposure
- LE takes 3 days to a week or more to develop
rem: PLE takes several hours to days so in the middle and no scarring
lupus erythematous diagnosis
biopsy and serology are needed to support a dx of LE
management of PLE
- graded early phototherapy (due to the fact that if they receive graded increase in exposure using UVB the skin appears to become less likely to develop PLE= hardening )
- or avoid the sun
- short course of prednisolone if cant be avoided
- topical steroids can be used but little efficacy
- sedative ah1 for itch
how long does it take for solar urticaria to develop
5-10 mins within exposure to UVR or visible light get widespread sheets of urticaria and itch
how long does it take for the rash of solar urticaria to disappear
couple of hours
what can trigger solar urticaria
drugs or infection
pathology of urticaria
- mas cell degranulation with UVR or visible light as a signal
- IgE probably
- transimissible serum factor
diagnosis of solar urticaria
- clinical dx
- quick to develop whereas PLE takes 6 hours and LE days to weeks
-body area also maps exposure although some sites eg face can be less sensitive
management solar urticaria
-UVR or even visible light avoidance H1 blockade an be trialled -gradual increase in UV exposure- HARDENING -omit drug if relevant in hx -omalizumab anti IgE in severe cases
porphyrias what are they
-rare group of inherited disorders which can affect many organs
pathology of porphyrias and which light spectrum
- due to an enzymatic defect in haem biosynthesis with the result that substrate prior to the enzyme block build up
- get build up of porphyrin and porphyrin precursors
- some of these precursors are photosensitive so cause the cutaneous reaction
- upon exposure to blue visible light (>400nm) these photosensitiers release free radicals that cause inflammation
diagnosis of porphyrias
-measure porphyrins in either blood, plasma or stool
two main types of derm porphyrias
- porphyria cutanea tarda PCT
- erythropoietic protoporphyria EPP
main cause of porphyria cutanea tarda
usually the result of any liver damage eg alcohol viral hepatitis
coupled with an inherited predisposition
clinical features of porphyria cutanea tarda
- most on back of hands and on face
- rash does NOT immediately follow UVR
- physical signs are
- erosions, blisters, crusts
- milia= end result of above
- hyperpigmentation and hypertrichosis- most seen on temples
- hypertrichosis= excess hair growth
diagnosis of PCT
-clinical
biopsy
porphyrins levels
treatment PCT
- treat underlying liver disease
- phlebotomy every 2 weeks
- chloroquine is useful
erythropoietic protoporphyria EPP when is the onset
usually early childhood
-can present later in life
small child starts screaming within minutes of being placed in sunshine and then develops a rash
EPP
clinical features of EPP
- exposure to sunshine presents with almost immediate burning pain
- and erythema and oedema over several hours
- waxy plaques and scarring may develop
organ complication of EPP
can develop liver disease
dx and treatment
- porphyrin levels
- sun avoidance and sunblocks
- beta carotene
diff dx of solar urticaria
- PLE
- LE
- EPP- so check porphyrins levels
pseudoporphyrias what is it
Similar clinical picture to PCT but without measurable abnormalities of porphyrins may be seen in some patients with renal failure or those on NSAID or contraceptive pill
examples of phytodermatoses
- psoralen makes you more photosensitive -therefore used in careful doses in PUVA
- strimmer’s disease -plant sap contains photosensiters
presentation of phototoxicity and drug induced photosensitivity
-sunburn like
-ertyhema and scaling and peeling
-blistering and then marked hyperpigmentation a few weeks later
chronic over time can develop eczema or lichen planus like
individual uses a strimmer when gardening and wears only shorts. next day he is covered by hundres of linear blisters 10-15 cm long like whipped
strimmer disease
-strimmer has cut the plant and released their sap containing topical photosensitisers which have been deposited against the skin and then UVR exposure has caused the phototoxic rash
drugs that induce photosensitivity
- quinine
- ciprofloxacin
- nalidixic acid
- some tetracyclines
diagnosing drug induced photosensitivity
- phototest patient whilst still on the drug -if reaction is abnormal then stop the drug
- re-phototest some time after to confirm change in status
as long as rash is not life threatening eg TEN
what is SPF
sun protection factor
measure of protection against UVR induced erythema
eg SPF 2 means 50% of UVR is allowed through
20=5% but in real life and application usually means about 1/3 of this
markers of chronic UVR exposure 6
- skin atrophy - back of the hand is thinner eg
- telangiectasia- reflects collagen loss
- variation in skin vascularity- weather beaten
- variation in epidermal melanin pigmentation with both areas of hyper and hypopigmentation
- increased fine wrinkling
- focal areas of fine scaling reflecting subclinical actinic keratoses
solar elastosis presentation and pathology
-alteration in collagen secondary to UVR leads to fragmentation of fibres and an apparent increase in volume
yellow appearance
cyst and comedones
disorders made worse by UVR
- herpes simplex
- rosacea
- very active psoriasis UVR can provoke a rash and areas of normal sunburn can koebenerise into psoriatic plaques
disorders improved with UVR
-psoriasis eczema
acne
what is chronic actinic dermatitis
-patients are very sensitive to UVR mostly middle aged or older men rash on the nape of neck and face eczema worsened by UVR hx of other dermatitis diagnostic phototesting grossly abnormal
what are the main morphological types of drug reactions6
- urticaria
- TEN
- fixed drug
- AGEP
- DRESS
- measles like-maculopapular
drugs causing urticaria response
- penicillins
- radiological contrast- but different mechanism through hyperosmolar stress causing mast cell degranulation
what is the most common cutaneous reaction to a drug
maculopapular exanthema - measles like
presentation of maculopapualr rash
erythematous
macular in some places and papular in others
sometimes itch
how so after taking medication will a maculopapular rash appear
4 to 21 days after
rash seen with glandular fever and penicillin is normally quicker
what are important drug reactions
-DRESS
-blisters
mucosal involvement
target lesions of erythema multiforme
necrolysis/ TENS
TEN management
stop drug ASAP
DRESS meaning
drug reaction with eosinophilia and systemic symptoms
presentation of DRESS
-widespread rash (erythrodermic)
-can be eczematous
with or without facial oedema
-pupura on lower legs
-lymphadenopathy
-pyrexia
-hepatitis
-nephritis
how soon after drug does DRESS appear
2 weeks
so may no longer be on drug
main precipitants of DRESS 4
carbamazepine
phenytoin
allopurinol
dapsone
pathology of DRESS
-much of the reaction seems to be an immunological response to reactivation of latent viral infection such as herpes and CMV
prognosis of DRESS
last for several weeks or more
mortality of 10% from hepatitis
management of DRESS
supportive care
stop causative drug
systemic steroids
fixed drug reaction presentation
and where most common
and why name fixed
red round plaques with erythema and even blistering that resolves leaving marked hyperpigmentation
rash occurs on a single or multiple body site
and reoccur at same site if drug used again hence FIXED
most common on genitalia, lips or acral skin
assoc. drugs to fixed drug reaction
-NSAID
penicillins
what is AGEP
acute generalised exanthematous pustulosis
presentation of AGEP
-characterised by a fever and widespread pustular rash that resembles pustular psoriasis
management of AGEP
systemic steroids
worrying drug reactions
- blister
- mucosal disease
- TEN
- DRESS
pigmentary disorders main ones to know
- vitiligo
- albinism
- melanism
what disorders can cause both post-inflammatory hyperpigmentation and hypopigmentation
eczema
DLE
what is vitiligo
acquired focal loss of pigmentation due to immunological attack on melanocytes in the skin
-no functional melanocytes
genetics vitiligo
20% concordance in monozygotic twins
not mendelian
clinical features of vitiligo
- sharply demarcated macular areas of depigmentation
- symmetrical
- hair may lose pigment too
- sometimes limited to one or more body segments
- genitalia, mouth eyes and hands are preferentially affected
assoc. to vitiligo
organ specific autoimmune disorders such as pernicious anaemia and addison’s
diff dx of vitiligo
- piebladism- if present at birth more likely to be piebaldism which is an inherited pigmentary disorder that clinically resembles vitiligo but is due to a KIT gene mutation
- LSEA and pityriasis versicolor
- pityriasis alba in eczema
- leprosy with loss of cutaneous sensation
treatment of vitiligo and prognosis
- no treatment
- some resolve spontaneously without treatment
- more extensive and longer the worse prognosis
- topical steroids and calcineruin inhibitors
- phototherapy in dark skin
- epidermal transplants
- camouflage
albinism pathology
autosomal recessive disorders in which the amount of melanin produced by melanocytes is reduced
number of melanocytes is the same
risks with albinism
- skin cancer more UVR exposure
- poor visual acuity and nystagmus as loss of pigment in retina and iris
main gene assoc. to albinism
tyrosinase
melasma /cholasma presetnation
appears as brown/ grey patches on the cheeks and forehead commonly seen in pregnancy and is a result of increased melanin pigmentation
precipitants of melasma
pregnancy
oestrogen OCP
treatment for melasma
-sunscreen
azelaic acid
topical retinoids
how does rosacea differ to acne
- not primarily a follicular disorder
- no comedones
clinical features of rosacea
-erythema
telangiectasia
flushing
possible sensory symptoms
oedema of facial skin with papules and pustules
-rhinophyma= hyperplasia of sebaceous glands with fibrotic overgrowth of derms
-ocular symptoms and signs
NO COMEDONES
where is rosacea most common
nose and cheeks
who does rosacea affect
- middle age
- pale skin or red hair
- worse in men
pathology of rosacea 2
unknown
not infectious
-neurovascular: with transient erythema and flushing leading to persistent erythema and telangiectasia. also get burning skin and vascular changes with oedema
-inflammatory: marked perivascular and perifollicular lymphohistocytic infiltrate with sebaceous gland overgrowth and possible graunolma formation
what is ocular rosacea and management
- rosacea can affect the eyes without any skin signs or with
- blepharitis, keratitis, chalazia, scleritis and uveitis
- untreated can lead to corneal scarring
- if dont respond to antibiotics then refer to opthalmology
what is rhinophyma and cause
gross sebaceous gland hyperplasia and dermal fibrous tissue leading to tissue overgrowth
enlarged nose
treatment of rosacea
- general skin care- avoid irritants, soaps and UVR
- alcohol and spicy food tend to make telangiectasia and flushing worse
- topical brimonidine tartare a selective a1a adrengeric agonist improves erythema
- lasers for telangiectasia
- in mild disease can use topical antibiotics- metronidazole, azelaic acid, ivermectin
- if topical agents fail use systemic eg tetracyclines or metronidazole
- isotretinoin systemically
- rhinophyma requires surgical treatment with dermabrasion or shaving
what should you not treat rosacea with
topical steroids
vasoconstriction and then gets worse
differentials for rosacea 3
- acne vulgaris- comedones
- sebhorreic dermatitis- scaly, nasolabial fold, dandruff
-perioral dermatitis hx of steroid use
perioral dermatitis clinical features
- most common young women
- presence of papules, pustules and erythema with or without small degree of scaling around the mouth
what causes perioral dermatitis
-use of topical steroids on the face or steroid inhalers
management of perioral dermatitis
- sudden withdrawal of steroid makes rash worse
- need to gradually withdraw steroid
- systemic tetracyclines as a cover whilst gradually withdraw steroid
advice on prescribing topical steroids for face
DONT PRESCRIBE UNLESS SURE OF DX
- make rosacea worse
- cause perioral dermatitis
sebhorreic dermatitis and dandruff cradle cap
clinical features
who gets it and where
- erythematous and scaly lesion
- seen in areas of rich sebum production
- young middle aged adults
pathophysiology of seb d
-immunological or inflammatory response to the yeast called pityrosporum which lives and metabolises lipids on skin surface
where is seb d commonly found
sebum areas -face nasolabial folds forehead upper chest and back
who is more at risk of getting seb d
immunocompromised eg HIV can be more severe
dandruff vs seb d
same process
dandruff is just more mild variant with less erythema on the scalp
treatment of seb d
anti-yeast agents - azoles shampoo/ cream- ketoconazole
sometimes topical steroids
what does severe seb d possibly reflect
underlying HIV infection
diff dx
- rosacea- which is red with papules and pustules
- seb d is red and scaly
-psoriasis- often mixed up
lichen planus what is it
lichen planus is an inflammatory disorder of unknown cause characterised by intense itch and presence of violaceous polygonal plaques with frequent oral or mucosal involvement
who gets lichen planus
middle age more common
hep c infection
prognosis of lichen planus
-remits within 6 months to 1 yr in most but in some it persist
clinical features of lichen planus
- individual lesions are violet coloured and flat topped
- wickham’s striae- lace like pattern diagnostic of LP
- different morphological varitiers from annular to blistering
- INTENSELY ITCHING
main areas affected by lichen planus
wrist, forearms lower legs or feet
also get mucosal and nasal involvement
mucosal LP CF
LP can affect the oral mucosa and the genitalia where ulceration or erosion can occur
- see white mesh like pattern
- can affect scalp and cause scarring alopecia
nails LP
LP affects the nails where it may cause thinning, longitudinal ridging and a widespread pattern labelled as trachyonychia (where all the nails appear very thin with extensive shallow pits )
scarring and destruction of the nails can occur
lichen planus pathology
LP seems to be a T cell mediated disease in which it appears as though the body is trying to reject or kill off many of the keratinocytes
T cell infiltrate hugging the epidermis with occasional apoptosed keratinocytes called cytoid bodies
features resemble some changes seen in cutaneous graft vs host disease
diagnosis of lichen planus
usually clinical
histology can be helpful
diff dx of lichen planus
lichenoid drug reactions -T cell hugging the epidermis
treatment of lichen planus
-sedative antihistamines for itch
-topical steroids
-topical calcineurin inhibitors
short term systemic steroids
ciclosporin
complications of lichen planus
-scarring alopecia- leads to total hair loss- wont regrow
-severe oral disease
genital disease
two causes of scarring alopecia
lichen planus
LE
systemic lupus erythematous features
-butterfly +/- more extensive rash
systemic on heart , kidneys …
what is discoid lupus erythematous CF
produces red scaly plaques most commonly on face and head
producing and leading to scarring
usually photosensitive rash so made worse by UVR exposure
and if involving hair areas causes scarring alopecia
post-inflammatory hypopigmentation or hyperpigmentation may occur
diagnosis of DLE
clinical suspicion
biopsy
serology unhelpful as DNA markers often absent
treatment DLE
-avoid sun
use sun block
topical steroids
antimalarials
sub acute lupus eythematous what is it
-half way house between DLE and systemic lupus
-some progress to systemic
more likely to have antibody serology than DLE
presentation of sub acute lupus
- photosensitivity
- scaly red placques over face or upper trunk which resemble psoriatic plaques
or can get annular lesions with central clearing and scale
often sun exposed sites eg shoulder, backs, chest and arms
scarring uncommon but can get depigmentation
diagnosis of sub acute LE
biopsy
serology - Ro AND La are often positive
phototesting
clinical
treatment of sub acute LE
- widespread so topical steroids less useful
- antimalarials - work less well than DLE
- systemic steroids
lupus tumidus presentation
patients develop erythematous nodules almost resembling urticaria (which are fixed) and generally without scale
-photosensitive
lupus profundus what is it
deeper inflammation of sub-cutaneous tissue
pityriasis rosea presentation
- very common
- rash characterised by annular erythematous patch with a colarette of scale
- initial lesion often on upper chest is known as herald patch consisting of a pink brown patch or plaque with a raised edge
- a week to 10 days later numerous other scaly red lesions develop most commonly on trunk
- chrisstmas tree
- tends to be mildly itchy
diagnosis of pityriasis rosea
-dont need biopsy
-
cause of pityriasis rosea
response to a virus
diff dx pityriasis rosea
herald patch- eczema, ringworm
trunk - syphilis, psoriasis
management pityriasis rosea
-none
may give topical steroids or emoilients to help
icythoses pathology
-widespread scaly lesion where inflammation is not usually prominent
-epidermis
-mutations in proteins important for kertainocyte differentiation eg filaggrin , transglutaminase
or producion of lipids eg steroid sulphatase deficiency
or caused by an internal malignancy
therefore
-most are inherited
but some are acquired
icythosis vulgaris mutation
filaggrin gene
presentation of ichythosis vulgaris
- diffuse polygonal scaling
- tends to spare flexures
- keratosis pilaris-rough and bumpy skin
- hyperlinear palms
assoc. to icthosis vulgaris
1/3 of patients will have atopic dermatitis as filaggrin mutations are also assoc. with atopic dermatitis
(atopic dermatitis usually only have mutation on one allele whereas IV have on both)
inherited vs acquired ichythosis
acquire develops in adulthood
inherited either at birth or develops in childhood
cause of acquired ichythosis
-underlying malignancy usually lymphoma
night sweats and weight loss
-drugs
malnutrition
what is keratosis pilaris
-in half of the population so very normal
-occurs on backs of upper arm and over triceps in young people
-follicular plugging with a rim of erythema around the follicle
no symptomatic
assoc. keratosis pilaris
ichythosis
atopic eczema
erythroderma what is
refers to widespread erythema >90% involvement of body
or papulosquamous rash
very uncomfortable
commonest causes of erythroderma
- psoriasis
- atopic dermatitis or other eczema forms
- drug reactions
- cutaneous T cell lymphoma
rarer cause of erythroderma
undlering malignancy lymphomas especially
risks and management of erythroderma
- fluid loss: as thermoregulation is impaired and sweat gland duct occlusion can lead to an inability to lose heat causing hyperthermia. Or can be hypothermic due to volume of blood flowing near surface
- hypothermia is often concealaed and more likely one- as patient looks hot and feels warm to touch but the core temp is reduced
- rigours, shivers and malaise
management of erythroderma
-admit skilled nursing emoilients topical steroids systemic steroids ciclosporin retinoids watchful waiting
necrobiosis lipoidica presentation
- YELLOW or red patch with marked telangiectasia that looks like “lipid”
- mainly on shins
- can be raised but can be atrophic or ulcerate
necrobiosis lipoidica condition assoc.
diabetes
treatment of Necrobiosis
- watchful waiting can be better
- topical steroids
- systemic steroids
granuloma annulare presentation
another necrobiotic disorder
-annular lesions made up of lots of individual papules, nodules with a smooth skin surface and no scale
histological features of necrobiosis
collagen with histiocytes appearance
shows necrobiosis
treatment of granuloma annulare
-most resolve no treatment
-topical steroids
intralesional steroids
lichen sclerosis et atrophicus LSEA WHAT DOES it affect
skin or mucosa or genitals
presentation of LSEA
- atrophic wrinkled skin
- white
- atrophy of dermis can lead to blistering and bleeding into blisters
- scarring
risk of LSEA
Chronic risk of LSEA on genitals is assoc, with an increased risk of SCC
and may lead to narrowing of the urethral meatus and destruction of the introitus secondary to scarring
management of LSEA
- topical steroids eg clobetasol propionate
- of if penile involvement extensive- circumcision
Morphoea presentation
classically presents initially as a violet macule, which develops central sclerosis with a lilac ring
- atrophy
- can involve fascia, muscles or bones
morphoea prongosis
- usually mild and spontaneously resolves
- more severe variants include muscle and bone
treatment for morphoea
-topical steroids
-systemic steroids
PUVA
erythema ab igne cause
secondary to infared damage to blood vessels due to sitting close to radiators or a fire
-reticular pattern reflects normal vessel anatomy
-elderly
-blue red reticulated pattern that leaves permanent or semi-perm hyperpigmentation
granny tartan
keloids what are they and cause
-keloids occur following surgery or inflammatory processes such as acne when instead of a neat scar developing there is an overgrowth or excess producion of collagen
where and who are keloids most common
-upper 1/3 body
-african ancestry
young people
strong fhx
poor surgical technique
infection
treatment of keloids
- intralesional steroids
- re-excision of lesion can be considered after this but can make it worse
two clinical types of impetigo
bullous- less common
non-bullous- more common
what causes impetigo 2
-staph aureus
beta haemolytic strep can cause non bullous
pathology of impetigo
- self-inoculation of pathogenic bacteria elsewhere on skin or in the nasophraynx or sometimes following an insect bite or atrophic dermatitis induced scratching
- blisters in staph impetigo are due to local toxin production against desmoglein 1 only
clinical features of impetigo 5
- most commonly seen in children on face around nose and mouth
- early lesions are characterised by presence of small vesicles which may be clear and rupture. subsequently blisters >1cm ,which are pus filled may then be seen
- usually surrounded by scabs and characteristic golden crusted exudate
- lesions may itch and scratching results in further inoculation of surrounding areas
- leucocytosis is common, lymphadenopathy
treatment of impetigo and diagnosis
- sample the blister or swab
- crust remove with wet dressings
- topical antibiotics eg mupirocin or fusidic acid if localised
- topical antiseptic eg chlorhexidine
- systemic anti-staph flucox or cephalosporin
complication of impetigo
-glomerulonephritis
folliculitis what is it
inflammation centrered around hair follicle
cause of folliculitis
infective bacteria or fungi
non infective
mostly bacterial and self -limiting
presentation of folliculitis
- inflammation around hairs-erythema
- can be pain and itch
- pustule looking things but not pustules as if a pustule is centered on a follicle then it is folliculitis
- can also get actual pustules not centered around the follicles
folliculitis boil presentation
furuncle
deeper and larger and more painful focus of infective folliculitis
if larger called a carbuncle - which get many boils clustered together so have multiple openings
most common infective causes of folliculitis
-staph
candida
herpes simplex
gram negative- seen in patients who have been treated with tetracyclines or other abx for acne
non infective causes of folliculitis
emoilients or tar therapy
predisposing factors for folliculitis
- excess sweating
- occlusion and maceration
- obesit and diabetes
- topical or systemic steroids
- oilu skin care preparations eg emoilients greasy or tar
what is blue jean folliculitis refer to
refers to folliculitis that appears secondary to friction and maceration from wearing tight clothes against skin
also truck drivers
what is hot tub folliculitis and what causes it
-infection from pseudomonas
treatment of folliculitis
- most resolve spontaneously
- topical antiseptics eg chlorhexidine if needed
- topical chemotherapeutic agents such as fusidic acid or mupirocin
cellulitis what is it
cellulitis is inflammation of the deep dermis and subcutaneous tissue usually due to infection
what is erysipelas
inflammation usually due to strep infection of the deep dermis
erysipelas vs cellulitis
- erysipelas more common face
- erysipelas has sharper and palpable edge
but dont get too hung up in difference just call both cellulitis if in doubt
clinical presentation of cellulitis
- elderly
- unilateral area of erythema on the lower leg with oedema, pain and local warmth
- rarely can get blisters
- pyrexia and malaise
- elevated WCC
- negative blood culutres usually
- signs of severe sepsis can be present
- occasionally can be ascending painful lymphangitis and lymphadenopathy
- sometimes obvious focal for bacterial entry - local wound
- can affect any region
- broaden antibiotics for immunosuppressed
main causative agent of cellulitis
-strep or staph
diagnosis of cellulitis
frequently over diagnosed
clinical dx
treatment of cellulitis
- IV abx eg benzylpenicillin and flucox
- sometimes oral can be used
diff dx of cellulitis
- contact allergic eczema - often on bacground of venous disease
- necrotising fasciitis -erythema, malaise, collapse, crepitiations
-pseudocellulitis- hypodermitis but actually represents an early stage of lipodermatosclerosis secondary to venous insufficiency
usually bilateral with erythema skin thickening tightness and no systemic features
- panniculitis- erythema nodosum- vasculitis
- carcinomous infiltration eg breast -rare
dermatomyophyte infections tinea clinical presentation
- annular erythematous scaly eruption with or without pustules
- active edge-hence the phrase ringworm
diff dx tinea
eczema
management of tinea 2
- topical agents eg azole cream
- topical terbinafine
when does topical azole cream not work for tinea 3
- scalp dermatophyte infection
- dermatophyte infection of nails
- tinea incognito
dx of tinea skin disease
do A SCRAPING IF IN DOUBT
scalp tinea presentation
-erythema alopecia scale pustules kerion: boggy inflammation swelling
treatment of scalp tinea
-need also systemic treatment with oral terbinafine or systemic azoles or griseofulvin
presentation of tinea nails
pitting
ridging
oncholysis
dystrophy
treatment of tinea nails
need systemic terbinafine or systemic azoles
>3 months for nails
IMPORTANT note regarding tinea treatment
NEVER COMMENCE TREATMENT OF TINEA WITHOUT TAKING A SCRAPING AND GETTING A POSITIVE DX
what is tinea incognito
when tinea has been misdx as eczema and topical steroids applied
-initially both dr and patient think it is getting better but the steroids dampen down the immune response, resulting in spread of the fungal infection which subsequently flares with marked erythema and pustules when steroids are stopped
candida risk factors
diabetes
pregnancy
steroids or immunosuppression
occult neoplasia
angular stomatitis / cheilitis may indicate
ill fitting dentures
and treat with steroid/ azole cream
cutaneous candida location
favours warm moist areas such as under breasts, folds of skin due to obesity (intertriginous areas)
presentation of cutaneous candida
-presents as satellite lesions
well demarcated bright red areas
little bit of scaling
diff dx of candida
- psoriasis and eczema
- in children in nappies diff dx is irritant dermatitis secondary to ammonia
how to differentiate candida from irritant dermatitis nappy rash
- candida penetrates the depths of folds
- irritant dermaitits does not permeate the skin folds as ammonia doesnt
treatment of candida
azole and steroid cream
complication of candida in men
can cause balantitis
sexual intercourse
pityriasis versicolor cause
due to yeast infection malassezia
when is pityriasis versicolor often noticed
after a summer holiday
presentation of pityriasis versicolor
presents as a dull red/ light brown scaly plaques on upper chest and back which when scratched release abdundant scale
but upon exposure to sun the affected area often appears paler than the surrounding area and progresses to leave pale non scaly areas which are most apparent after sun exposure
dx of pityriasis versicolor
can be done using the scale and potassium hydroxide
treatment of pityriasis versicolor
imidazole shampoo eg ketoconazole
can recurr
common warts verrucae vulgaris presentation
- typically acral so on hands and feet in younger children
- hyperkeratotic plaques or nodules
- point like dermal vessles or black specks
- in flexures can be more papillomatous
- on feet pressure forces them inwards so can be painful
what virus is assoc to viral warts
HPV
risk factor for viral warts
immunosuppressed
what are plane warts
also HPV infections commonly seen on back of hands or face as tiny little flat topped papules which often markedly pigment after sun exposure
treatment of HPV warts
- salicylic acid
- cryotherapy
- curettage
- electrodessication
- contact sensitiers
- laser
molluscum contagiosum cause
due to pox virus infection spread by direct contact
risk factors for mollscum
mostly in children
if in adults think immunosuppression eg HIV
presentation of molluscum
- lesion, papules or nodules have a characteristic shiny white centre and central umbilication
- in childhood often get eczema around and bleeding due to scratching
management molluscum
leave alone
6months should disappear
herpes simplex presentation
-gingivo-stomatitis often in young children with oral ulcers and blisters
can be systemic disturbance
recurrent as latent
herpes simplex labialis= cold sores
signs of reactivation of simplex
-tingling sensation
papule formation
clustering or grouping of lesions
blister formation
what precipiates re-occurrence of simplex
- UVR exposure
- other illnesses eg fever blisters
treatment of uncomplicated cutaneous herpes simplex
topical aciclovir
but needs to be early in the onset
eczema herpeticum who gets it
mostly in children with atopic dermatitis
presentation of eczema herpeticum
- hundreds or thousands of punched out ulcerated lesions
- children become sick and pused to be fatal due to pneumonia or encephalitis
- misdiagnosed as impetiginised eczema
dx and treatment of eczema herpteicum
skin scrapings and PCR
management of eczema herpeticum
systemic aciclovir not topical
herpes neonatorum is
primary infection with herpes simplex from a HSV mother during childbirth to infant
management of mother with active genital herpes
do a c-section
herpes varicella zoster virus
how is chicken pox spread
via air droplets
incubates for 3 weeks
presentation of chicken pox
start as red macules then form vesicles, pustules and then crust
occurs in crops so different stages of evolution in different crops
-itchy so get scratched off leaving scars
where does VZV remain after chickenpox
in dorsal root ganglion
why is primary varicella or chicken pox a problem in adults
they get a more severe illness with pyrexia malaise and potentially fatal varicella pneumonia
-immunocompromised
why is primary varicella or chickenpox an issue in pregnancy
in first trimester causes foetal abnormalities
in third trimester can cause spontaneous abortion or premature birth
also risk if close to birth the child will be born with disseminated varicella at birth
shingles percentage
10-20%
presentation of shingles
dermatomal pattern of vesicles on red base which then pustulate crust and may scar
pain usually preceds the lesion
complication of shingles
-post herpetic neuralgia- chronic pain following
-trigeminal involvement
ocular kertitis
facial nerve palsy
treatment of shingles
aciclovir can shorten course
if immunosuppresed should use IV agents
scabies presentation and cause
-sarcoptes scabei mite
-very itchy
-worse itch at night
burrows are linear structures which is where the eggs are laid- usually in palms, soles finger webs
-nodules common around nipples and genitalia
-excoriation
pathology of scabies
produces a type 4 hypersensitivity reaction to the eggs or faeces it produces
therefore cell mediated response so symptoms appear 3 weeks following infestiation
how do you catch scabies
has to be close physical contact
what is crusted scabies
norwegian scabies
-massively hyperkeratotic widespread crusting resembling severe psoriasis
risk factors for crusted scabies
down syndrome
immunosuppressed
unable to scratch
dx of scabies
-hx
family members and itch
-examine the whole patient including genitalia and interdigital folds
- can push a needle into the burrow and a mite will attach to the needle and then examine under microscope
- need to identify the mite as can lead to under or over treatment
treatment of scabies
-permethrin or malathion commonly used-
-warm bath
-wash bedding and clothin in hot cycle
all individuals in close contact need treating otherwise get re-cycle of infection
-ivermectin for crusted scabies
even carriers or asymptomatic need treatment
perdiculosis capitis head lice cause
due to infestation with pediculus humanus capitis
itchy scalp with secondary excoriation
nits are the eggs
treatment head lice
remove them
these two treatments only kill off the mites but down remove the nits
malathion
permethrin
pediculosis corporis body lice what is it
-infeciton of body
itching scratching and excoriation
poor hygiene
treatment of pediculosis corporis
washing all clothes
what is dermatitis artefacta
- skin lesions that are self -inflicted without any obvious cause
- eg blue ink rash
- young women using acid to bleach to needles
- bizarre rashses that dont fit
- level of insight varies
- psychology input needed and MDT
cutaneous dysmorphobia what is it
-patients presents with a mark on their skin which to all intents and purposes seems trivial but is having a sever impact on their life
delusions of infestation- parasitophobia
- say they want help as various creatures living on their skin
- need psychiatric input
- can respond to neuroleptic pimozide
Non accidental injury what skin diseases can be mis diagnosed as it
-LSEA
ehlers danlos syndrome get easy bruising and scarring as first cutaneous signs
hyper pigmentation signs in pregnancy
linea nigra
melasma or cholasma- which is the deep brown/ grey pigmentation of the skin most prominent on the cheeks and forehead
(also seen on those on COCP)
-hyperkeratosis can occur in some women on the nipples
what happens to melanocytic nevi in pregnancy
increase in size
darken
or become more vascular
what can happen at stretch marks
can get PEP or PUPP
what can change about hair in pregnancy
can get hypertrichosis
and after birth telogen effluvium
what happens to eczema in pregnancy
tends to get worsse
what happens to psoriasis in pregnnacy
tends to get better
pemphigoid gestationis presentation
blister disease in pregnancy
diagnosis of pemphigoid gestationis
pathology (eosinophils and subepidermal blisters)
immunoflourosence positive c3 and IgG on basement membrane
management of pemphigoid gestationis
topical steroids
sedative antihistamines
systemic steroids may be required
risks of pemphigoid gestationis
-can be increased risk of prematurity and small for dates
greater severity greater risk
main diff dx of pemphigoid gestationis
PEP
prognosis of pemphigoid gestationis in future pregnnacies
if same father then rash likely to recur and be more severe in future pregnancies
usually flare at time of delivery
polymorphic eruption of pregnancy what is it
common
polymorphic different presentation
presentation of PEP
-itchy red papules in the third trimester close to birth or just after delivery
-can also see widespread erythema and small vesicles
-plaques of eczema like
lesions are located preferentially in striae
sparing of umbilical region is characteristic
rash spreads from abdomen to other parts of trunk and limbs
pep vs pemphigoid gestationis
pemphigoid gestationis
- doesnt favour striae
- doesnt avoid the umbilicus
- tends to occur earlier in the final trimester or before
- biopsy for it looks like pemphigoid
- pemphigoid is less common and can occur in future pregnancies
treatment of PEP
-steroids and antihistamines
systemic steroids occasionally
intrahepatic cholestasis of pregnancy presentation
-intense generalised pruritus usually in the late second or third trimester
-no primary skin lesions
just excoriations as its itchy
inx for intrahepatic cholestasis
serum bile acid raised
risks of intrahepatic cholestasis
can be risk of foetal loss, prematurity and foetal distress
management of intrahepatic cholestasis
make sure no primary skin disease caushing itch and leave to obstetrics
atopic eruption of pregnancy what is it
-most common itchy disorder of pregnancy and can either occur in those who are known to have atopic dermatitis or atopic
-eczematous and papular with or without xerosis
atopic dermatitis
when does atopic eruption of pregnancy tend to occur
first trimester
management of atropic eruption of pregnancy
as for atopic dermatitis with topical agents
parvovirus rash is
slapped cheek
risk of slapped cheek rash contact
-risk in pregnancy is to the foetus if the mother has no immunity
foetal loss
dx based on IgM
obstetrics
drugs for derm that need consideration in pregnancy
- systemic retinoids
- methotrexate; both men and women
- azathioprine- avoid in pregnancy
- sedative antihistamines -chlorphenamine can be used cautiously - avoid non sedative
- PUVA is not safe
- UVB is safe
- topical steroids can be used but may change dose and potency -discuss with obstetrics
- tetracyclines dont use
- use erythromycin
hirsutism is
male pattern of growth of hair in females
hypertrichosis
excessive hair on any part of the body -may involve lanugo, vellus or terminal hair
mostly vellus hairs becoming terminal
3 stages of hair cycle
anagen
catagen
telogen
hirsutism conditions to consider 4
congenital adrenal hyperplasia
adrenal tumours
cushing
PCOS
inx for hirsutism
-hx menstrual periods, fhx
other signs of virilisation- enlarged clitoris, hirsutism, acne
inx -testosterone sex hormone binding globulin prolactin DHEAS dehydropiandrosterone sulphate
management of hirsutism
-non cutaneous cause refer to endo
for most there is no underlying endo cause to be found
-local treatment- wax, bleach, elctrolysis
laser
topical eflornithin an orthinine decarboxylase inhibitor
endocrine give anti androgens eg finasteride or cyproterone with oestrogens
hypertrichosis is
growth of hair longer and thicker and more obvious that would expect at different sites
switch from vellus to terminal
conditions that get hypertrichosis 4
malnutrition
anorexia
dermatomyositis
porphyria cutanea tarda
what is androgenic alopecia
male pattern baldness
reflects sensitivity to androgens resulting in a change from terminal hairs to vellus hairs and then loss of hairs
treatments for adnrogenetic alopeccia
- minoxidil topical
- systemic finasteride
- hair transplant from posterior occiput
telogen effluvium is
a clinical syndrome of hair loss several months after a major life event eg pregnancy or illness
the insult causes many hairs to exit anagen simultaneously into catagen
several months later they then fall out into telogen synchronously - so lots of hair fall out at once which makes it obious
the hair does return when the hair cycle gets back into asynchronous
chemotherapy induced effluvium
- rapid loss of hair over days seen in patients who are on chemo
- cytotoxics destroy fast dividing cells eg hair follicles
mechanism of chemo induced effluvium
-premature move to catagen
anagen hairs falling out
later telogen loss
can sometimes be irreversible hair loss if hair stem cells killed by chemo
alopecia areata is
characterised by sharply demarcated coin shaped areas of hair loss mostly on scalp or beard
-any age common in early adulthood or childhood
alopecia areata clinical sign
exclamation mark hairs- bulb of follicle becomes dot as get broken hair stumps
non scarring
prognosis of alopecia areata
-non scarring
most it regrows normally
can be white initially and then darkens
can get over whole body alopecia totalis
management of alopecia areata
-watch and wait
-topical steroid injection
induction of contact allergic sensitivity can stimulate hair growth
-short burst of systemic steroids early in disease
-wig in severe cases
chronic diffuse alopecia causes
- most common is androgenetic hair loss
- systemic malignancy
- renal liver failure
- hypo hyper thyroidism
- iron deficiency
- drugs
drugs that can cause a chronic diffuse alopecia
antithyroid retinoids azathioprine
2 main causes scarring alopecia
- discoid lupus
- lichen planus
neurofibromatosis pathology
autosomal dominant
mutations in the neurofibromin 1 NF1 or 2 gene
perphieral neurofibromatosis is due to mutations in NF1
presentation of neurofibromatosis
-cafe au lait spots >5 is abnormal
-axillary freckling
neurofibromas (soft, pressure sensation)
-flexiform large sub-cutaneous neurofibromas
-lisch nodules (iris hamartoma)
-CNS tumours (eg gliomas) and tumours elsewhere
pathology tuberous sclerosis
autosomal dominant
presentation of tuberous sclerosis
- ash leaf macules, oval areas of depigmentation present at birth
- connective tissue nevi, known as shagreen patches
- angiofibromas, commonly seen on the face
- periungal fibromas
- seizures and cognitive impairment
what is acanthosis nigricans
-presents as brown hyperkeratotic velvety/ warty areas in the axillae, neck and the groins and at other skin friction sites
-areas develop lots of skin tags
histologically resembles seb k
what causes acanthosis nigricans 2
assoc. to underlying malignancies and paraneoplastic phenomenon as they produce circulating growth factors that affect the skin’s frictional area
- also assoc. to insulin resistance in obesity and type 2 dm
dermatomyositis is
an autoimmune disorder more common in women characterised by a range of skin changes and myositis -muscle weakness
presentation of dermatomyositis
-proximal muscle weakness before rash or vice versa
on skin get
- violet lilac rash around the eyes
- erythematous rash that can appear in a photosensitive distriubtion
- violaceous lichenoid rash along dorsal surface of hands and fingers= gottron’s papules
- painful cuticles and prominent nail fold capillaries
cause of dermatomyositis
also a paraneoplastic disease with 50% having underlying malignancy
dx of dermatomysoitis
-skin biopsy looks like LE
-serum creatinine kinase can be raised
ANA positive in 50% of cases
management of dermatomyositis
- inx underlying tumour
- high dose prednisolone
children and dermatomyositis
can occur in children but not a paraneoplastic disease
hereditary haemorrhagic telangiectasia cause
autosomal dominant
small AV malformation
not telangiectasia
where is HHT seen
lips oral nasal mucosae skin hands and GI
presentation HHT
flat red spots
nose bleeds
anaemia
what causes destruction of the nails
-psoriais lichen planus immunobullous SCC melanoma
what is oncholysis
separation of the distal nail from nail bed
diseases causing oncholysis
-psoriasis
dermatophyte infection
trauma
thyroid rare
what causes pitting of nails
psoriasis
eczema
lichen planus- trachyonychia
alopecia areata
what causes ridges in nails
psoriasis
eczema
fungal
what causes horizontal ridging in nails
mees lines
beau reil grooves
cytotoxics
trauma
what does myxoid cyst represent
cystic outgrowth from the distal joint
gelatinous material can be expressed from cyst if ruptured
pressure from cyst causes nail dystrophy due to pressure on nail matrix
management of myxoid cyst
-surgery if symptomatic
kolionychia what it is and sign of
sign of iron deficiency
spoon like
what causes green nails
colonisation of pseudomonas aerguinosa
topical abx
what is melanoychia
brown longitudinal streak in nail
what is melanoychia a sign of
-common in people with dark skin
but in light skin it either reflects a benign nevus pigmentation or a melanoma - use Hutchinson’s sign
hutchinson’s sign
pigmentation in the nail fold likely to be melanoma
spread of pigmentation from a nail to the surrounding skin
inx of melanoychia
exposure of dorsal matrix and biopsy
surgery if suspect melanoma
main cause of blue black nail 2
haematoma- possible hx of trauma
melanoma - Hutchinson sign
paronychia is
inflammation around the nail usually due to chronic infection gaining access via an abnormal cuticle eg in eczema
main cause of acute paronychia
staph infection- pain swelling erythema
who gets chronic paronychia
-atopic
industrial exposure of hands
chronic candia infection?
management chronic paronychia
-topical anti candida agents with or without steroids
erythema nodosum causes
N-not known idiopathic O- ocp, pregnancy drugs-penicillins o s-sarcoidosis u-ulcerative colitis, crohn, bechet m-microscopy-strep mycobacteiral and malignancy
