Dermatology Flashcards
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acanthosis nigricans clinical fx
symmetrical, brown, velvety plaques that are often found on the neck, axilla and groin
causes acanthosis nigricans
type 2 diabetes mellitus
gastrointestinal cancer
obesity
polycystic ovarian syndrome
acromegaly
Cushing’s disease
hypothyroidism
familial
Prader-Willi syndrome
drugs
combined oral contraceptive pill
nicotinic acid
acanthosis nigricans patho
insulin resistance → hyperinsulinemia → stimulation of keratinocytes and dermal fibroblast proliferation via interaction with insulin-like growth factor receptor-1
actinic keratoses definition
a common premalignant skin lesion that develops as a consequence of chronic sun exposure
clinical fx actinic keratoses
small, crusty or scaly, lesions
may be pink, red, brown or the same colour as the skin
typically on sun-exposed areas e.g. temples of head
multiple lesions may be present
actinic keratoses mx
sun avoidance/cream
fluorouracil cream: typically a 2 to 3 week course. The skin will become red and inflamed - sometimes topical hydrocortisone is given following fluorouracil to help settle the inflammation
topical diclofenac: may be used for mild AKs. Moderate efficacy but much fewer side-effects
topical imiquimod
cryotherapy
curettage and cautery
sedating antihistamines
chlorpheniramine
non sedating antihistamines
loratidine
cetirizine
athlete’s foot cause
tinea pedis…genus Trichophyton
1st line tx athlete’s
topical imidazole, undecenoate, or terbinafine
bowen’s disease definition
a type of precancerous dermatosis that is a precursor to squamous cell carcinoma
bowen’s disease epid
elderly pts
clinical fx bowen’s disease
red, scaly patches
often 10-15 mm in size
slow-growing
often occur on sun-exposed areas such as the head (e.g. temples) and neck, lower limbs
bowen’s disease mx
topical 5-fluorouracil
typically used twice daily for 4 weeks
often results in significant inflammation/erythema. Topical steroids are often given to control this
cryotherapy
excision
bullous pemphigoid definition
an autoimmune condition causing sub-epidermal blistering of the skin
bullous pemphigoid patho
secondary to the development of antibodies against hemidesmosomal proteins BP180 and BP230
bullous pemphigoid epid
elderly pts
clinical fx bullous pemphigoid
itchy, tense blisters typically around flexures
the blisters usually heal without scarring
there is stereotypically no mucosal involvement
inv bullous pemphigoid
immunofluorescence - IgG and C3
mx bullous pemphigoid
oral corticosteroids
immunosupressants and abx
burns
cherry haemiangioma define
benign skin lesions which contain an abnormal proliferation of capillaries
cherry haemangioma prev
advancing age
men and women equally
clinical fx cherry haemiangioma
erythematous, papular lesions
typically 1-3 mm in size
non-blanching
not found on the mucous membranes
dermatofibroma define
common benign fibrous skin lesions.
dermatofibroma patho
abnormal growth of dermal dendritic histiocyte cells, often following a precipitating injury
clinical fx dermatofibroma
solitary firm papule or nodule, typically on a limb
typically around 5-10mm in size
overlying skin dimples on pinching the lesion
ersipelas definition
localised skin infection caused by Streptococcus pyogenes. In simple terms, it is a more superficial, limited version of cellulitis.
erysipelas tx
flucloxacillin
erythema ab igne definition
a skin disorder caused by over exposure to infrared radiation
clinical fx erythema ab igne
reticulated, erythematous patches with hyperpigmentation and telangiectasia
prev erythema ab igne
elderly woman (sit next to open fire)
erythema ab igne associated risk
if not tx may go onto develop S.C.C
erytheme multiforme definition
a hypersensitivity reaction that is most commonly triggered by infections. It may be divided into minor and major forms.c
clinical fx erythema multiforme
target lesions
initially seen on the back of the hands / feet before spreading to the torso
upper limbs are more commonly affected than the lower limbs
pruritus is occasionally seen and is usually mild
causes erythema multiforme
viruses: herpes simplex virus (the most common cause), Orf*
idiopathic
bacteria: Mycoplasma, Streptococcus
drugs: penicillin, sulphonamides, carbamazepine, allopurinol, NSAIDs, oral contraceptive pill, nevirapine
connective tissue disease e.g. Systemic lupus erythematosus
sarcoidosis
malignancy
erythema multiforme major associated
mucosal involvement
erythrasma clinical fx
asymptomatic, flat, slightly scaly, pink or brown rash usually found in the groin or axillae
erythrasma cause
n overgrowth of the diphtheroid Corynebacterium minutissimum
erythrasma examination
Wood’s light reveals a coral-red fluorescence
erythrasma tx
Topical miconazole or antibacterial
oral erythromycin if extensive
hereditary haemorrhagic telangiectasia inheritance
aut dom
diagnostic criteria HHT
2 = possible
3 or more = definitive
epistaxis
telangiectases: multiple at characteristic sites (lips, oral cavity, fingers, nose)
visceral lesions: for example gastrointestinal telangiectasia (with or without bleeding), pulmonary arteriovenous malformations (AVM), hepatic AVM, cerebral AVM, spinal AVM
family history: a first-degree relative with HHT
hidradenitis suppuravita definition
a chronic, painful, inflammatory skin disorder. It is characterized by the development of inflammatory nodules, pustules, sinus tracts, and scars in intertriginous areas.
HS when suspected
pubertal or post-pubertal patients who have a diagnosis of recurrent furuncles or boils, especially in intertriginous areas
HS epidemiology
women
<40
patho HS
Chronic inflammatory occlusion of folliculopilosebaceous units that obstructs the apocrine glands and prevents keratinocytes from properly shedding from the follicular epithelium.
HS risk fx
Family history
Smoking
Obesity, diabetes, polycystic ovarian syndrome
Mechanical stretching of skin
HS clinical fx
recurrent, painful, and inflamed nodules.
HS occurs most commonly on intertriginous skin. However, non-intertriginous skin involvement also can occur. The axilla is the most common site
Other areas include inguinal, inner thighs, perineal and perianal, inframammary skin.
The nodules may rupture, discharging purulent, malodorous material.
Coalescence of nodules can result in plaques, sinus tracts and ‘rope-like’ scarring
HS mx
good hygeine and loose fitting clothes
smoking cessation
weight loss
acute flares - steroids or fluclox
topical clindamycin or oral abx
lumps excised
HS complications
Sinus tracts, fistulas
Comedones
Scarring - severe scarring can lead to dense, rope-like bands in the skin with strictures and lymphedema
Contractures
Lymphatic obstruction
hyperhidrosis first line
topical aluminium chloride
hyperhidrosis other mx options
iontophoresis: particularly useful for patients with palmar, plantar and axillary hyperhidrosis
botulinum toxin
surgery: e.g. Endoscopic transthoracic sympathectomy
keratoacanthoma define
a benign epithelial tumour.
keratoacanthoma age
advancing age
clinical fx keratoacanthoma
olcano or crater
initially a smooth dome-shaped papule
ddx keratoacanthoma
S.S.C
koebner phenomenon when occurs
psoriasis
vitiligo
warts
lichen planus
lichen sclerosus
molluscum contagiosum
lentigo maligna define
a type of melanoma in-situ. It typically progresses slowly but may at some stage become invasive causing lentigo maligna melanoma.
leukoplakia define
a premalignant condition which presents as white, hard spots on the mucous membranes of the mouth
leukoplakia risk fx
smokers
leukoplakia how diagnosed and ddx
a diagnosis of exclusion. Candidiasis and lichen planus should be considered, especially if the lesions can be ‘rubbed off’
monitoring of leukoplakia
biopsy and regular f/u to exclude S.C.C
lichen planus clinical fx
itchy, papular rash most common on the palms, soles, genitalia and flexor surfaces of arms
rash often polygonal in shape, with a ‘white-lines’ pattern on the surface (Wickham’s striae)
Koebner phenomenon may be seen (new skin lesions appearing at the site of trauma)
oral involvement in around 50% of patients: typically a white-lace pattern on the buccal mucosa
nails: thinning of nail plate, longitudinal ridging
causes of lichenoid drug eruptions
gold
quinine
thiazides
mx lichen planus
potent topical steroids
benzydamine mouthwash if oral
lichen sclerosus definition
an inflammatory condition that usually affects the genitalia and is more common in elderly females. Lichen sclerosus leads to atrophy of the epidermis with white plaques forming
clinical fx lichen sclerosus
white patches that may scar
itch is prominent
may result in pain during intercourse or urination
mx lichen sclerosus
topical steroids and emollients
why follow up lichen sclerosus
increased risk of vulval cancer
lipoma patho
generally found in subcutaneous tissues
rarely, they may also occur in deeper adipose tissues
malignant transformation to liposarcoma is very rare
lipoma epidemiology
common
middle age adults
lump characteristics lipoma
smooth
mobile
painless
lipoma mx
observed
liposcarcoma fx
Size >5cm
Increasing size
Pain
Deep anatomical location
livedo reticularis define and clinical fx
an purplish, non-blanching, reticulated rash caused by obstruction of the capillaries resulting in swollen venules
causes livedo reticularis
idiopathic (most common)
polyarteritis nodosa
systemic lupus erythematosus
cryoglobulinaemia
antiphospholipid syndrome
Ehlers-Danlos Syndrome
homocystinuria
define milia
mall, benign, keratin-filled cysts that typically appear around the face. They may appear at any age but are more common in newborns
molloscum contagiosum caused
caused by molluscum contagiosum virus (MCV), a member of the Poxviridae family
molluscum contagiosum spread
Transmission occurs directly by close personal contact, or indirectly via fomites (contaminated surfaces) such as shared towels and flannel
molloscum contagiosum incidence
children (with atopic eczema)
age 1-4
clinical fx molluscum contagiosum
pinkish or pearly white papules with a central umbilication, which are up to 5 mm in diameter. Lesions appear in clusters in areas anywhere on the body (except the palms of the hands and the soles of the feet). In children, lesions are commonly seen on the trunk and in flexures, but anogenital lesions may also occur. In adults, sexual contact may lead to lesions developing on the genitalia, pubis, thighs, and lower abdomen.
self care advice molluscum contagiosum
reassure
within 18 mths resolve
lesions contagious…avoid sharing
not scratch
eclusde from school, gym or swimming not necessary
molloscum contagiosum tx
not usually recommending
Squeezing (with fingernails) or piercing (orange stick) lesions may be tried, following a bath. Treatment should be limited to a few lesions at one time
Cryotherapy may be used in older children or adults, if the healthcare professional is experienced in the procedure
if itching similar to eczema and if infected topical fusidic acid
molluscum contagiosum referral
people who are HIV-positive with extensive lesions urgent referral to a HIV specialist
For people with eyelid-margin or ocular lesions and associated red eye urgent referral to an ophthalmologist
Adults with anogenital lesions should be referred to genito-urinary medicine, for screening for other sexually transmitted infections
mycosis fungoides define
a rare form of T-cell lymphoma that affects the skin
mycosis fungoides fx
itchy, red patches which are
lesions tend to be of different colours in contrast to eczema/psoriasis
pellegra cause
nicotinic acid (niacin) deficiency
pellagra clinical fx
3 D’s - dermatitis, diarrhoea and dementia
risk fx pellagra
a consequence of isoniazid therapy (isoniazid inhibits the conversion of tryptophan to niacin) and it is more common in alcoholics
pemphigus vulgaris define
an autoimmune disease caused by antibodies directed against desmoglein 3, a cadherin-type epithelial cell adhesion molecule
pemphigus vulgaris incidence
Ashkenazi Jewish population
fx pemphigus vulgaris
mucosal ulceration
skin blistering - flaccid, easily ruptured vesicles and bullae. Lesions are typically painful but not itchy. These may develop months after the initial mucosal symptoms. Nikolsky’s describes the spread of bullae following application of horizontal, tangential pressure to the skin
acantholysis on biopsy
pemphigus vulgaris mx
steroids
immunosuppressants
periorificial dermatitis incidence
women 20-45 yrs
steroids
clinical fx periorficial dermatitis
clustered erythematous papules, papulovesicles and papulopustules
most commonly in the perioral region but also the perinasal and periocular region
skin immediately adjacent to the vermilion border of the lip is typically spared
mx periorficial dermatitis
avoid steroids
topical or oral abx
pityriasis vesicolour define and cause
a superficial cutaneous fungal infection caused by Malassezia furfur
pityriasis vesiclour fx
most commonly affects trunk
patches may be hypopigmented, pink or brown (hence versicolor). May be more noticeable following a suntan
scale is common
mild pruritus
predisposing fx pityriasis vesicolour
healthy individuals
immunosuppression
malnutrition
Cushing’s
pityriasis vesicolour tx
topical antifungals - ketoconazole shampoo
if not work consider other diagnosis
polymorphic eruption of pregnancy when
last trimesterp
PE of preg clinical fx
lesions often first appear in abdominal striae
the periumbilical area is often spared
PE of preg mx
emollients, mild potency topical steroids and oral steroids
pompholyx define
a type of eczema which affects both the hands (cheiropompholyx) and the feet (pedopompholyx)
pompholyx preciptated
humidity and high temps
pompholyx fx
small blisters on the palms and soles
pruritic
often intensely itchy
sometimes burning sensation
once blisters burst skin may become dry and crack
pompholyx mx
cool compresses
emollients
topical steroids
porphyria cutanea tarda define and patho
the most common hepatic porphyria. It is due to an inherited defect in uroporphyrinogen decarboxylase or caused by hepatocyte damage e.g. alcohol, hepatitis C, oestrogen
porphyria cutanea tarda fx
photosensitive rash with blistering and skin fragility on the face and dorsal aspect of hands (most common feature)
hypertrichosis
hyperpigmentation
porphyria cutanea tarda inv
urine: elevated uroporphyrinogen and pink fluorescence of urine under Wood’s lamp
mx porphyria cutanea tarda
cholorquine
venesection
port wine stain define
vascular birthmarks that tend to be unilateral. They are deep red or purple in colour
port wine stain prog
get darker
do not resolve
port wine stain tx
cosmetic camouflage or laser therapy
causes of pruritus
liver disease
iron def anaemia
polycythaemia
CKD
lymphoma
causes of purpura in adults
- Immune thrombocytopenic purpura
- Bone marrow failure (secondary to leukaemias, myelodysplasia or bone metastases)
- Senile purpura
- Drugs (quinine, antiepileptics, antithrombotics)
- Nutritional deficiencies (vitamins B12, C and folate)
causes of purpura in children
Meningococcal septicaemia
* Acute lymphoblastic leukaemia
- Congenital bleeding disorders
- Immune thrombocytopenic purpura
- Henoch-Schonlein purpura
- Non-accidental injury
pyoderma gangrenosum define
a rare, non-infectious, inflammatory disorder. It is an uncommon cause of very painful skin ulceration
pyoderma gangrenosum patho
AKA neutrophilic dermatosis
neutrophilic dermatoses are skin conditions characterised by dense infiltration of neutrophils in the affected tissue and this is often seen on biopsy
causes pyoderma gangrenosum
idiopathic
IBD
RA
SLE
myeloproliferative disorders
lymphoma
myeloid leukaemias
monoclonal gammopathy (IgA)
granulomatosis with polyangiitis
primary biliary cirrhosis
fx pyoderma gangrenosum
typically on the lower limb
soften at the site of a minor injury as in this patient’s case and this is known as pathergy
initially features:
usually starts quite suddenly
small pustule, red bump or blood-blister
later features:
the skin then breaks down resulting in an ulcer which is often painful
the edge of the ulcer is often described as purple, violaceous and undermined.
the ulcer itself may be deep and necrotic
may be accompanied by systemic symptoms
fever
myalgia
pyoderma gangrenosum mx
oral steroids
pyogenic granuloma define
a relatively common benign skin lesion
factors risk pyogenic granuloma
trauma
pregnancy
women and young adults
fx pyogenic granuloma
most common sites are head/neck, upper trunk and hands. Lesions in the oral mucosa are common in pregnancy
initially small red/brown spot
rapidly progress within days to weeks forming raised, red/brown lesions which are often spherical in shape
the lesions may bleed profusely or ulcerate
mx pyogenic granuloma
if preg associated resolve spotaneously post partum
curettage and cauterisation, cryotherapy, excision
adverse effects of retinoids
teratogenicity
females should ideally be using two forms of contraception (e.g. Combined oral contraceptive pill and condoms)
dry skin, eyes and lips/mouth
the most common side-effect of isotretinoin
low mood
whilst this is a controversial topic, depression and other psychiatric problems are listed in the BNF
raised triglycerides
hair thinning
nose bleeds (caused by dryness of the nasal mucosa)
intracranial hypertension: isotretinoin treatment should not be combined with tetracyclines for this reason
photosensitivity
salmon patches define
vascular birthmark
pink and blotchy, and commonly found on the forehead, eyelids and nape of the neck. They usually fade over a few months, though marks on the neck may persist.
sebaceous cyst patho
a proliferation of epidermal cells within the dermis. Pilar cysts (also known as trichilemmal cysts or wen) derive from the outer root sheath of the hair follicle.
clinical fx sebaceous cyst
most common scalp, ears, back, face, and upper arm (not palms of the hands and soles of the feet).
They will typically contain a punctum.
sebaceous cyst tx
excision to prevent recurrence
seborrhoeic keratoses
benign epidermal skin lesions seen in older people
seborrhoeic keratoses fx
large variation in colour from flesh to light-brown to black
have a ‘stuck-on’ appearance
keratotic plugs may be seen on the surface
seborrhoeic keratosis mx
reassurance
removal include curettage, cryosurgery and shave biopsy
ddx of shin lesions
erythema nodosum
pretibial myxoedema
pyoderma gangrenosum
necrobiosis lipoidica diabeticorum
pretibial myxoedema
symmetrical, erythematous lesions seen in Graves’ disease
shiny, orange peel skin
necrobiosis lipoidica diabeticorum
shiny, painless areas of yellow/red skin typically on the shin of diabetics
often associated with telangiectasia
atopic eruption of pregnancy
the commonest skin disorder found in pregnancy
it typically presents as an eczematous, itchy red rash.
no specific treatment is needed
pemphigoid gestationis
pruritic blistering lesions
often develop in peri-umbilical region, later spreading to the trunk, back, buttocks and arms
usually presents 2nd or 3rd trimester and is rarely seen in the first pregnancy
oral corticosteroids are usually required
possible skin manifestations of SLE
photosensitive ‘butterfly’ rash
discoid lupus
alopecia
livedo reticularis: net-like rash
spider naevi define
a central red papule with surrounding capillaries. The lesions blanch upon pressure
ddx spider naevi
differentiated from telangiectasia by pressing on them and watching them fill. Spider naevi fill from the centre, telangiectasia from the edge
associations of spider naevi
liver disease
pregnancy
combined oral contraceptive pill
strawberry naevi when
first mth of life
Strawberry naevus
clinical fx
erythematous, raised and multilobed tumours.
Typically they increase in size until around 6-9 months before regressing over the next few years (around 95% resolve before 10 years of age).
Common sites include the face, scalp and back. Rarely they may be present in the upper respiratory tract leading to potential airway obstruction
strawberry
naevi increased risk
female
premature
mother had chorionic villous sampling
strawberry
naevi complications
mechanical e.g. Obstructing visual fields or airway
bleeding
ulceration
thrombocytopaenia
strawberry naevus tx
propranolol
3 types of tinea
tinea capitis - scalp
tinea corporis - trunk, legs or arms
tinea pedis - feet
scalp ringworm complications
scarring alopecia
if untreated scalp ringworm
a raised, pustular, spongy/boggy mass called a kerion
scalp ringworm cause
Trichophyton tonsurans in the UK and the USA
may also be caused by Microsporum canis acquired from cats or dogs
scalp ringworm diagnosis
Microsporum canis green fluorescence under Wood’s lamp*. However the most useful investigation is scalp scrapings
mx of scalp ringworm
terbinafine for Trichophyton tonsurans infections and griseofulvin for Microsporum infections. Topical ketoconazole shampoo should be given for the first two weeks to reduce transmission
general ringworm causes
Trichophyton rubrum and Trichophyton verrucosum (e.g. From contact with cattle)
general ringworm clinical fx
well-defined annular, erythematous lesions with pustules and papules
general ringworm tx
may be tx with oral fluconazole
athlete#s foot clinical fx
itchy, peeling skin between the toes
toxic epidermal necrolysis define
a potentially life-threatening skin disorder that is most commonly seen secondary to a drug reaction
TEN clinical fx
a scalded appearance over an extensive area
systemically unwell e.g. pyrexia, tachycardic
positive Nikolsky’s sign: the epidermis separates with mild lateral pressure
drugs which induce TEN
phenytoin
sulphonamides
allopurinol
penicillins
carbamazepine
NSAIDs
TEN mx
stop precipitating factor
supportive care
often in an intensive care unit
volume loss and electrolyte derangement are potential complications
intravenous immunoglobulin now first line
small vessel vasculitis
ANCA-associated vasculitides
granulomatosis with polyangiitis (Wegener’s granulomatosis)
eosinophilic granulomatosis with polyangiitis (Churg-Strauss syndrome)
microscopic polyangiitis
immune complex small-vessel vasculitis
Henoch-Schonlein purpura
Goodpasture’s syndrome (anti-glomerular basement membrane disease)
cryoglobulinaemic vasculitis
hypocomplementemic urticarial vasculitis (anti-C1q vasculitis)
medium vessel vasculitis
polyarteritis nodosa
Kawasaki disease
large vessel vasculitis
temporal arteritis
Takayasu’s arteritis
clinical fx zinc deficiency
acrodermatitis: red, crusted lesions
acral distribution
peri-orificial
perianal
alopecia
short stature
hypogonadism
hepatosplenomegaly
geophagia (ingesting clay/soil)
cognitive impairment
acne patho
disease of pilosebaceous unit
acne describe
comedones - open if blackhead, closed if whitehead
papules, pustules
nodules, cysts
scarring
acne v drug induced acne
drug induced - monomorphic - pustules in steroid used
severe form of acne
acne fulminans - systemic upset
tx with hospital admission and oral steroids
severe acne character
extensive lesions, nodules, pitting, scarring
mild to mod acne mx
12 week course of topical combo-
a fixed combination of topical adapalene with topical benzoyl peroxide
a fixed combination of topical tretinoin with topical clindamycin
a fixed combination of topical benzoyl peroxide with topical clindamycin
mod to severe acne mx
12 week course of topical + maybe oral:
a fixed combination of topical adapalene with topical benzoyl peroxide
a fixed combination of topical tretinoin with topical clindamycin
a fixed combination of topical adapalene with topical benzoyl peroxide + either oral lymecycline or oral doxycycline
a topical azelaic acid + either oral lymecycline or oral doxycycline
teracyclines c/i
pregnant or breastfeeding
children less than 12
how long abx therapy in acne used for
no more than 6 mths generally
what prescribe with abx in acne
topical retinoid or benzoyl peroxide to reduce abx resistance
long term abx use in acne complication
gram negative folliculitis - give trimethoprim
acne options for fertile woman
COCP - co-cyprindiol - anti androgen (increased VTE risk)
when refer for acne
conglobate acne: a rare and severe form of acne found mostly in men that presents with extensive inflammatory papules, suppurative nodules (that may coalesce to form sinuses) and cysts on the trunk.
patients with nodulo-cystic acne
consider referral acne
mild to moderate acne has not responded to two completed courses of treatment
moderate to severe acne has not responded to previous treatment that includes an oral antibiotic
acne with scarring
acne with persistent pigmentary changes
acne is causing or contributing to persistent psychological distress or a mental health disorder
what bacteria in acne vulgaris
Propionibacterium acnes
alopecia mx
topical or intralesional corticosteroids
topical minoxidil
phototherapy
dithranol
contact immunotherapy
wigs
alopecia prognosis
hair regrow in 50% by 1 yr and mostly all eventually
basal cell hx
slow growth
local invasion
mets rare
sun exposed sites
basal cell describe
pearly, flesh coloured papule with telangiectasia
may ulcerate and leave central crater
referral BCC
routine
mx of BCC
surgical removal
curettage
cryotherapy
topical cream: imiquimod, fluorouracil
radiotherapy
burns types
superficial epidermal- painful and red, dry, no blisters
partial thickness - pale pink, blistered, slow CRT
partial thickness, - white and non blanching ertherma, reduced sensation, pain to deep pressure
full thickness - white/bnrown/black, no blisters or pain
features of CHRONIC PLAQUE psoriasis
erythematous plaques with silvery white scales
extensor surfaces or trunk, scalp, buttocks
clear demyelination between normal and affected skin
auspitz sign
2 types of contact dermatitis
irritant contact dermatitis: common - non-allergic reaction due to weak acids or alkalis (e.g. detergents). Often seen on the hands. Erythema is typical, crusting and vesicles are rare
allergic contact dermatitis: type IV hypersensitivity reaction. Uncommon - often seen on the head following hair dyes. Presents as an acute weeping eczema which predominately affects the margins of the hairline rather than the hairy scalp itself. Topical treatment with a potent steroid is indicated
common cause of dermatitis
cement
dermatitis herpetiformis patho
deposition of IgA in dermis
fx of dermatitis herpetiformis
itchy, vesicular lesions on extensor surfaces
diagnosis of dermatitis hermitofrmis
skin biopsy - iga
mx of dermaittis herpetiformis
dapsone
gluten free diet
define eczema herpeticum
severe primary infection of the skin by herpes simplex virus 1 or 2.
eczema herpeitcum present
rapidly progressing painful rash
clinical fx of eczema herpeticum
monomorphic punched-out erosions (circular, depressed, ulcerated lesions) usually 1-3 mm in diameter are typically seen.
how mx eczema herpeticum
admit
IV acliclovir
eczema steroid strengths
mild - hydrocortisone
mod - betamethasone valerate
potent - fluticasone propionate 0.05, betamethasone valerate
very potent - clobetasol propionate
how much steroid use eczeme
1 finger tip = twice size of adult hand
define erythrema nodosum
inflammation of subcut fat
presentation erythrema nodosum
typically causes tender, erythematous, nodular lesions
usually occurs over shins, may also occur elsewhere (e.g. forearms, thighs)
usually resolves within 6 weeks
lesions heal without scarring
causes erythema nodosum
infection - strep, TB
sarcoidosis
IBD
malignancy or lymphoma
drugs - penicillin, sulphonamide, COCP
preg
define erythroderma
more than 95% of the skin is involved in a rash of any kind.
causes of erythroderma
eczema
psoriasis
drugs e.g. gold
lymphomas, leukaemias
idiopathic
triggers of erythroderma
withdrawal of steroidsmx
mx of erythroderma
admit
causative organsmis of fungal nail infections
dermatophytes
account for around 90% of cases
mainly Trichophyton rubrum
yeasts
account for around 5-10% of cases
e.g. Candida
non-dermatophyte moulds
risk fx of fungal nail infections
age
DM
psoriasis
repeated trauma
fx of fungal nail
unsightly
thickened, rough, opaque
ddx of fungal nail
psoriasis
trauma
yellow nail syndrome
ix of fungal nail
nail clippings +/- scrapings of the affected nail
microscopy and culture
fungal nail mx
if asx and pt unbothered - no tx
if limited involvement (≤50% nail affected, ≤ 2 nails affected, more superficial white onychomycosis): topical treatment with amorolfine 5% nail lacquer; 6 months for fingernails and 9 - 12 months for toenails
if more extensive involvement due to a dermatophyte infection: oral terbinafine is currently recommended first-line; 6 weeks - 3 months therapy is needed for fingernail infections whilst toenails should be treated for 3 - 6 months
if more extensive involvement due to a Candida infection: oral itraconazole is recommended first-line; ‘pulsed’ weekly therapy is recommended
guttate psoriasis triggers
strep infection 2-4 weeks ago
fx of guttate psoriasis
tear drop papules on trunks or limbs
mx of guttate
resolve within 2-3 mths
topical agents as per psoriasis
UVB phototherapy
tonsillectomy may be necessary with recurrent episodes
ddx of guttatr
pityriasis rosea
hirscutism causes
PCOS
Cushing’s syndrome
congenital adrenal hyperplasia
androgen therapy
obesity: thought to be due to insulin resistance
adrenal tumour
androgen secreting ovarian tumour
drugs: phenytoin, corticosteroids
assessment of hirscuitism
Ferriman-Gallwey scoring system: 9 body areas are assigned a score of 0 - 4, a score > 15 is considered to indicate moderate or severe hirsutism
mx of hirscutiism
advise weight loss if overweight
cosmetic techniques such as waxing/bleaching - not available on the NHS
consider using combined oral contraceptive pills such as co-cyprindiol (Dianette) or ethinylestradiol and drospirenone (Yasmin). Co-cyprindiol should not be used long-term due to the increased risk of venous thromboembolism
facial hirsutism: topical eflornithine - contraindicated in pregnancy and breast-feeding
hypertrichosis what and causes
androgen independent hair growth
drugs: minoxidil, ciclosporin, diazoxide
congenital hypertrichosis lanuginosa, congenital hypertrichosis terminalis
porphyria cutanea tarda
anorexia nervosa
impetigo pathogen
staph aureus or strep pyogenes
more common in scabies
eczema or insect bites
how spread impetigo
direct contact and indirect
inc is 4-10 days
fx of impetigo
‘golden’, crusted skin lesions typically found around the mouth
very contagious
mx of impetigo
limited - hydrogen peroxide 1% or topical fusidic acid
extensive - oral flucoxacillin
school impetigo
children should be excluded from school until the lesions are crusted and healed or 48 hours after commencing antibiotic treatment
keloid scar mx
intra lesional steroids
excision not always possible and cause further scarring
keloid scar define
tumour-like lesions that arise from the connective tissue of a scar and extend beyond the dimensions of the original woun
risk fx keloid scar
ethnicity
young
sternum, shouldner, neck, face, extensor
lentigo maligna define
melanoma in-situ. It typically progresses slowly but may at some stage become invasive causing lentigo maligna melanoma.
malignant melanoma types
superficial spreading
nodular
lentigo maligna
acral lentiginous
superficial spreading
most common
growing mole
young people
nodular
second most common
sun exposed
middle aged
red or black lump which oozes or bleeds
lentigo maligna
older, chronic
acral lentiginous
rare
affects non exposured sights
darker skin pigment
subungal pigment - hutchinson’s sign or on palms or feet
diagnostic fx of malignant melanoma
changes in size, shape, colour
diameter = same or more >7mm
inflammation
oozing or bleeding
altered sensationma
malignant melanoma tx
excision biopsy and see if need re excision
may need sentinal node mapping or block dissection of regional LN’s
margins melanoma
breslow
0-1 mm = 1cm
1-2mm thick = 1-2cm
2-4mm thick = 2-3 cm
>4mm = 3cm
poor prog melanoma
breslow thickness
nickel dermaitis
allergic contact dermatitis and is an example of a type IV hypersensitivity reaction. It is often caused by jewellery such as watches
It is diagnosed by a skin patch test
pityriasis rosea patho
acute, self-limiting rash which tends to affect young adults. The aetiology is not fully understood but is thought that herpes hominis virus 7 (HHV-7) may play a role.
hx of pityriasis rosea
no prodrome, but a minority may give a history of a recent viral infection
herald patch (usually on trunk)
followed by erythematous, oval, scaly patches which follow a characteristic distribution with the longitudinal diameters of the oval lesions running parallel to the line of Langer. This may produce a ‘fir-tree’ appearance
mx of pityriasis rosea
self limited - 6-12 weeks
psoriasis increased risk
psoriatic arthropathy (around 10%)
increased incidence of metabolic syndrome
increased incidence of cardiovascular disease
increased incidence of venous thromboembolism
psychological distress
patho of psoriasis
genetic - twins
: abnormal T cell activity stimulates keratinocyte proliferation.
environment - trauma, stress, infection
types of psoriasis
plaque psoriasis: the most common sub-type resulting in the typical well-demarcated red, scaly patches affecting the extensor surfaces, sacrum and scalp
flexural psoriasis: in contrast to plaque psoriasis the skin is smooth
guttate psoriasis: transient psoriatic rash frequently triggered by a streptococcal infection. Multiple red, teardrop lesions appear on the body
pustular psoriasis: commonly occurs on the palms and soles
other fx of psoriais
nail signs: pitting, onycholysis, loss of nail, hyperkeratosis
arthritis
exacerbating fx of psoriasis
trauma
alcohol
drugs: beta blockers, lithium, antimalarials (chloroquine and hydroxychloroquine), NSAIDs and ACE inhibitors, infliximab
withdrawal of systemic steroids
Streptococcal infection
psoriasis mx
emollient
potent steroid once daily plus vit D analogue once daily, applied seperately for 4 weeks
if no improve after 8 weeks - vit d analogue
then no = potent steroids x2 daily or coal tar
secondary care - phototherapy narrowband ultraviolet B light
oral methotrexate, ciclosporin, biologics
scalp psoriasis mx
use of potent topical corticosteroids used once daily for 4 weeks
if no improvement after 4 weeks then either use a different formulation of the potent corticosteroid (for example, a shampoo or mousse) and/or a topical agents to remove adherent scale
face, flexural or genital psoriais mx
mild or moderate potency corticosteroid applied once or twice daily for a maximum of 2 weeks
s/e of steroids
atrophy, striae, rebound sx
how long steroids
4 week break before another course
potent for no longer than 8 weeks at a time or 4 week if very potent
how vit d analogues work
↓ cell division and differentiation → ↓ epidermal proliferation
reduce scale and thickness
vit d analogue c/i
pregnancy
dithranol how work and s/e
inhibits DNA synthesis
wash off after 30 mins
adverse effects include burning, staining
retinoids adverse effects
teratogenicity
females should ideally be using two forms of contraception (e.g. Combined oral contraceptive pill and condoms)
dry skin, eyes and lips/mouth
the most common side-effect of isotretinoin
low mood
whilst this is a controversial topic, depression and other psychiatric problems are listed in the BNF
raised triglycerides
hair thinning
nose bleeds (caused by dryness of the nasal mucosa)
intracranial hypertension: isotretinoin treatment should not be combined with tetracyclines for this reason
photosensitivity
rosacea fx
typically affects nose, cheeks and forehead
flushing is often first symptom
telangiectasia are common
later develops into persistent erythema with papules and pustules
rhinophyma
ocular involvement: blepharitis
sunlight may exacerbate symptoms
mx of rosacea
sunscreen
flushing - topical brimonidine gel
mild to mod - topical ivermectin
mod to severe - topical ivermectin and oral doxy
if not improved - laser therapy or if rhinophyma
ocular associations of rosacea
blepharitis conjunctivitis
scabies cause
Sarcoptes scabiei
fx of scabies
widespread pruritus
linear burrows on the side of fingers, interdigital webs and flexor aspects of the wrist
in infants, the face and scalp may also be affected
secondary features are seen due to scratching: excoriation, infection
mx of scabies
permethrin 5%
household contact
8-12 hours and repeat 7 days later
severe form of scabies
crusted norwegian scabies - HIV
tx with ivermectin
sebaceous cysts fx
punctum
sebaceous cyst mx
excision
seborrhoiec dermatitis what cause
Malassezia furfur - chronic dermitis
fx of seborrhoeic dermaittis
eczematous lesions on the sebum-rich areas: scalp (may cause dandruff), periorbital, auricular and nasolabial folds
otitis externa and blepharitis may develop
a
sscoiated conditions of seborrheic dermatiris
hiv
parkinsons
seborrheic dermaitis mx
ketoconazole shampoo
head and shoulder
if face - topical antifungals
shingles cause
herpes zoster infection
Following primary infection with VZV (chickenpox), the virus lies dormant in the dorsal root or cranial nerve ganglia.
fx of shingles
acute, unilateral, painful blistering rash caused by reactivation of the varicella-zoster virus (VZV)
risk fx shingles
age
HIV
steroids or chemo
deramtomes shingles
T1-L2
fx of shingles
prodromal period
burning pain over the affected dermatome for 2-3 days
pain may be severe and interfere with sleep
around 20% of patients will experience fever, headache, lethargy
rash
initially erythematous, macular rash over the affected dermatome
quickly becomes vesicular
characteristically is well demarcated by the dermatome and does not cross the midline. However, some ‘bleeding’ into adjacent areas may be seen
mx of shingles
infecrtious - avoid pregannt or immunocomp until vesicles crusted over or 5-7 days after
paracetamol and nsaids or amitripytlline, can use steroids if not immunocomp for pain
antivirals within 72 hours
complications of shingles
ost-herpetic neuralgia
the most common complications
more common in older patients
affects between 5%-30% of patients depending on age
most commonly resolves with 6 months but may last longer
herpes zoster ophthalmicus (shingles affecting affecting the ocular division of the trigeminal nerve) is associated with a variety of ocular complications
herpes zoster oticus (Ramsay Hunt syndrome): may result in ear lesions and facial paralysis
risk fx of S.C.C
excessive exposure to sunlight / psoralen UVA therapy
actinic keratoses and Bowen’s disease
immunosuppression e.g. following renal transplant, HIV
smoking
long-standing leg ulcers (Marjolin’s ulcer)
genetic conditions e.g. xeroderma pigmentosum, oculocutaneous albinism
clinical fx of S.C.C
sun-exposed sites such as the head and neck or dorsum of the hands and arms
rapidly expanding painless, ulcerate nodules
may have a cauliflower-like appearance
there may be areas of bleeding
tx of s.c.c.
surgical excision
4mm margins if <20mm or 6mm if >20mm
moh’s micrographic if high risk or cosmetic sites
poor prog S.C.C.
poorly differenitated
>20 mm in diameter
>4mm deep
immunosuppression
causes of SJS
penicillin
sulphonamides
lamotrigine, carbamazepine, phenytoin
allopurinol
NSAIDs
oral contraceptive pill
fx of SJS
the rash is typically maculopapular with target lesions being characteristic
may develop into vesicles or bullae
Nikolsky sign is positive in erythematous areas - blisters and erosions appear when the skin is rubbed gently
mucosal involvement (diff to TEN)
systemic symptoms: fever, arthralgia
SJS mx
admit
supportive tx
strawberry naebus
raised, multilobed tumours
can cause obstruction, bleeding or ulceration
resolve by 10 yrs of age
propranolol used as tx
venous ulceration where
above medial mallolus
ix of venous ulceration
ABPI - if 0.9-1.2 can use compression stocking, less = arterial
mx of venous ulceration
compression bandaging
oral pentoxifylline - vasodilator
vitilligo mx
sunblick
camoflage make up
steroids if applied in early changes
maybe tacrolismus or phototherapy
different atopy conditions with eczem
allergic rhinitis
asthma
food allergy
conjunctivits
eczema topical v oral alternative
topical calcineurin inhibitors - tacrolismus
oral ciclosporin
