Dermatology Flashcards
functions of the skin
STAIN B
Storage Thermoregulation Aesthetics + communication Immunological Neurological Barrier/protection
describe a rash structure
distribution - where is it:
- flexures/ extensors
- dermatomal
- intertriginous (folds of skin e.g. under breasts)
- photodistribution
configuration - grouping of the rash:
- linear
- annular (ring shaped)
- discoid (like a disc)
- clusters (infections!)
morphology - describe it
describe a skin lesion struction
Asymmetry Border: irregular/regular Colour Diameter Elevation/everything else
Eczema
aka
dermatitis
Eczema
acute dermatitis
rapidly evolving red rash which may be blistered or swollen
Eczema
chronic
longstanding irritable area
often darker, thickened (lichenified) and much scratched
Eczema
sub-acute
an inbetween state
Eczema
RFs (4)
- allergic rhinitis
- asthma
- age <5yrs
- FH of eczema
Eczema
where does it present in infants
extensors
cheeks
forehead
scalp
Eczema
where does it present in children and adults
flexures
Eczema
signs and symptoms
- pruritis
- xerosis (dry skin)
- erythematous
- scaly
- excoriations
- lichenification
Eczema
what does crust and weeping suggest
infections from staphylococcus
Eczema
what is atopic eczema
- prevalent in children
- FH of dermatitis or asthma
Eczema
what is allergic contact dermatitis
skin contact with substances that most ppl don’t react to
- nickel
- perfume
- rubber
- half dye
Eczema
what is irritant contact dermatitis
- provoked by bodily fluids, water, detergents, solvents/harsh chemicals, friction
- worse if has atopic eczema
Eczema
what is seborrheic dermatitis
irritation from toxic substances produced by Malassezia yeasts that live on the scalp and face
Eczema
what is nummular dermatitis
aka discoid
- may be set off initially by an injury
- scattered coin-shaped irritable patches
- persist for a few months
Eczema
what is gravitational dermatitis
- arises on lower legs of elderly
- due to swelling + poorly functioning leg veins
Eczema
what is infective dermatitis
provoked by impetigo (bacterial infection) or fungal infection
Eczema
trx for an acute flare
- emollients TDS
and
- topical corticosteroids (intermittent) e.g. hydrocortisone BD
Eczema
trx for chronic
- emollients
- continuous low-mid potent topical corticosteroid
- reduce exposure to triggers
- immunosuppressive agents
- biologics
- antihistamines, phototherapy, abx
Psoriasis
what is it
chronic autoimmune disease characterised by well demarcated, erythematous scaly plaques
Psoriasis
what are the different types
- chronic plaque
- flexural
- guttate
- pustular
- generalised/erythrodermic
Psoriasis
describe chronic plaque psoriasis
most common
- symmetrical plaques
- extensor (knees + elbows), scalp, lower back
- itchy
- well dermarcated circular to oval
- bright pink elevated lesion (plaque) w/ overlying white/silvery scale
Psoriasis
describe flexural (inverse) psoriasis
- smooth, erythematous plaques without scale
- in flexures + skin folds
Psoriasis
describe guttate psoriasis
- multiple, small tear dropped erythematous plaques
- on trunk
- after strep infection
- young adults
Psoriasis
describe pustular psoriasis
- multiple petechiae + pustules
- on palms + soles
Psoriasis
what is generalised/erythrodermic psoriasis
- rare but serious form
- erythroderma + systemic illness
Psoriasis
nail changes (3)
- nailbed pitting
- onycholysis
- sublungual hyperkeratosis
Psoriasis
nail changes: what is nailbed pitting
superficial depression in nailbed
Psoriasis
nail changes: what is onycholysis
seperation of nail plate from nail bed
Psoriasis
nail changes: what is subungual hyperkeratosis
thickening of nailbed
Psoriasis
RFs (4)
- FH
- HIV
- obesity
- smoking
Psoriasis
triggers
- skin trauma
- infection: strep, HIV
- drugs
- withdrawal of steroids
- stress
- alcohol + smoking
- cold/dry weather
Psoriasis
what is Koeber phenomenon
skin lesions occur at sites of skin injury (inc lichen planus + vitiligo too)
Psoriasis
which drugs can trigger psoriasis
BALI
BB
ACEi, anti-malarials (hydroxychloroquine)
Lithium
Indomethacin/NSAIDs
Psoriasis
chronic plaque mnx 1st line
regular emollient \+ potent corticosteroid (topical) OD \+ vit D analogue (topical) OD
Psoriasis
chronic plaque mnx 2nd line
vit D analogue BD
Psoriasis
chronic plaque mnx 3rd line
potent corticosteroid BD for up to 4w
or
coal tar preparation (OD/BD)
short acting dithranol can also be used
Psoriasis
systemic trx
1st: methotrexate
2nd: ciclosporin
3rd: Acitretin
Psoriasis
systemic trx: why monitor LFTs if giving methotrexate
hepatotoxicity
Psoriasis
systemic trx: why monitor FBCs if giving methotrexate
myelosuppression –> pancytopenia
Psoriasis
systemic trx: when can ciclosporin be used 1st line
if rapid control needed
or
palmoplantar pustulosis
or
considering conceptionPsoriasis
systemic trx: what are the SE’s of ciclosporin
5 H’s
- hypertrophy of gums
- hypertrichosis
- HTN
- Hyperkalaemia
- Hyperglycaemia
Psoriasis
systemic trx: what are the SE’s of Acitretin
- teratogenic
- hepatotoxicity
- increased lipids
Psoriasis
1st line phototherapy
narrowband UVB
Psoriasis
2nd line phototherapy
psoralen + UVA (PUVA)
Psoriasis
SE’s of phototherapy
- skin aging
- squamous cell cancer (not melanoma)
Psoriasis
what biological therapy can be used
- Infliximab
- Etanercept
- Adalimumab
Psoriasis
biological therapy: what is associated with Adalimumab
reactivation of latent TB
Acne Vulgaris
what is it
an inflammatory disease of the pilosebaceous unit
Acne Vulgaris
what is the pilosebaceous unit
hair follicles and sebaceous gland
Acne Vulgaris
how do non-inflammatory lesions present as
cornedones
Acne Vulgaris
how do less severe inflammatory lesions present as
papules
pustules
Acne Vulgaris
how do severe inflammatory lesions present
nodules
cyst
scarring
Acne Vulgaris
what is mild acne
- non inflammatory lesions
- w/ sparse inflammatory lesions
Acne Vulgaris
what is moderate acne
- widespread non inflammatory lesions
- w/ numerous papules + pustules
Acne Vulgaris
what is severe acne
- extensive inflammatory lesions
- inc nodules, pitting and scarring
Acne Vulgaris
aetiology
- ↑ sebum production
- ↑ androgens -> hyperplasia of sebaceous glands
- hyperactive immune response
- bacterial colonisation
Acne Vulgaris
complications
- post inflammatory pigmentation
- scarring
- deformity
- psychological + social effects
Acne Vulgaris
1st line (mild) mnx
topical benzoyl peroxide
Acne Vulgaris
2nd line (mild) mnx
topical abx or topical retinoid
Acne Vulgaris
3rd line (mod) mnx
- PO tetracyclines
or - PO anti-androgens
Acne Vulgaris
3rd line (mod) mnx: name some tetracyclines
- lymecyline
- oxtetracycline
- doxycycline
Acne Vulgaris
3rd line (mod) mnx: CI’s of tetracyclines
avoid in pregnant/breastfeeding women
avoid if <12 years
Acne Vulgaris
3rd line (mod) mnx: which abx can you used instead of tetracyclines in pregnant/breastfeeding women
erythromycin
Acne Vulgaris
3rd line (mod) mnx: what is the max duration of PO abx
3m
Acne Vulgaris
3rd line (mod) mnx: SE of long term abx use and what do you give if it occurs
gram -ve folliculitis
give high dose PO trimethoprim
Acne Vulgaris
3rd line (mod) mnx: name some PO anti-androgens
- OCP
- spironolactone
Acne Vulgaris
4th line (severe) mnx
PO retinoid
e.g. isotretinoin
Acne Vulgaris
4th line (severe) mnx: SEs of PO retinoid
- highly teratogenic
- hepatitis (moniter LFTs)
- dry mucous membrane
- headache
- hair thinning/loss
Rosacae
features
- 1st sx: flushing
- then persistent erythema w/ pustules + papules
- telangiectasia
- rhinophyma (large, red, bumpy nose)
Rosacae
where does it typically affect
nose, cheeks, forehead
Rosacae
how does it involve the eye
blepharitis
Rosacae
epidemiology
30-60yrs
F>M
common in pale skins
Rosacae
exacerbating factors
- sunlight
- hot weather
- warm baths
- stress
- spicy foods
Rosacae
mnx (general measures)
- camourflage creams
- sun protection
- avoid exacerbating factors
- emollient as a soap substitute if skin is dry
Rosacae
1st line mnx (mild)
topical metronidazole
Rosacae
what classes it as mild
limited number of papules and pustules and no plaque
Rosacae
2nd line mnx (for predominant flushing but limited telangectasia)
topical Azelaic acid / Brimonidine / Ivermectin
Rosacae
what can be used to manage persistent telangiectasia
laser therapy
Rosacae
mnx for severe cases
systemic abx: PO tetracyclines e.g. ocytetracycline
Viral Warts
where can they present on the body
cutaneous (aka veruca papilloma)
mucosal
Viral Warts
describe a cutaneous wart
- hard keratinous surface
- papillary capillaries (tiny red/black dots visible on wart)
Viral Warts
cause
- infection by HPV
- direct skin to skin contact or autoinoculation
Viral Warts
common wart
cauliflower like papulae
Viral Warts
plantar
- sole
- caused by HPV1, 2
Viral Warts
plane
- multiple small flat topped skin coloured papules
- often spread shaving
Viral Warts
filiform
- cluster of fine fronds emerging from pedicle base
- face
Viral Warts
butcher’s
HPV 7 infecting butcher’s hand
Viral Warts
epidermodysplasia veruciforms
- rare autosomal recessive
Viral Warts
mnx
- topical paints containing salicylic acid or podophyllin
- cryotherapy
- electrosurgery (curettage + cautery) for large resistant warts
cause of genital warts
HPV 6 or 11
spread by skin to skin contact
mnx of epidermoid and pilar cysts
none - most disappear
if red hot –> infected –> flucloxacillin
epidermoid cyst
location
face, neck, trunk
epidermoid cyst
central punctum?
yes
epidermoid cyst
origin
epithelium or hair follicle infundibulum
epidermoid cyst
cyst wall
delicate and prone to rupture
epidermoid cyst
histology
granular layer
epidermoid cyst
which syndrome is it present in
Gardner Syndrome
pilar cyst
location
scalp and scrotum
pilar cyst
central punctum?
no
pilar cyst
origin
outer root sheath
pilar cyst
cyst wall
thick + not prone to rupture
pilar cyst
histology
granular layer is absent
pilar cyst
what does it contain
keratinous material
pilar cyst
inheritance pattent
often autosomal dominant
Seborrhoeic Keratosis
what is it
a harmless warty spot and a common sign of skin ageing
Seborrhoeic Keratosis
presentation
- ‘stuck on’ appearance
- large variation in colour from flesh to light-brown to black
- fissured keratin surface.
Seborrhoeic Keratosis
mnx
- leave alone
- cryotherapy
- shave biopsy
- curettage
Dermatofibroma
what is it
a common benign fibrous nodule usually found on the skin of the lower legs
occurring at sites of previous trauma (insect bite)
Dermatofibroma
size
7-10mm
Dermatofibroma
presentation
- tethered to skin surface + mobile over sc tissue
- sometimes painful, tender, itchy
- Pinch Sign
- solitary dermal nodules
Dermatofibroma
what is Pinch Sign
the overlying skin dimples on pinching the lesion
Dermatofibroma
mnx
reassure
Dermatofibroma
histology
- proliferating fibroblasts
- merging w/ sparsely cellular dermal tissues
Shingles
cause
reactivation of the varicella zoster virus which an lie dormant in nerve ganglia following primary infection (chickenpox)
Shingles
commonly effects who?
elderly + young adults
Shingles
prodromal period features
- burning pain over affected dermatome
- fever, headache, lethargy
Shingles
which is the most commonly affected dermatome
T1-L2
Shingles
describe the rash
initially erythematous, macular rash over affected dermatome
becomes vesicular
well demarcated by the dermatome
doesn’t cross midline
Shingles
whom should pts avoid
pregnant women + the immunosuppressed
Shingles
when are pts infectious till
until the vesicles have crusted over
usually 5-7d following onset
Shingles
mnx to reduce risk of spread
cover lesions
Shingles
mnx: analgesia
1st line: NSAIDs + paracetamol
consider amitriptyline
severe + immunocompetent: PO corticosteroids 2w
Shingles
mnx
antivirals within 72hrs (aciclovir)
unless <50y + mild truncal rash w/ mild pain + no underlying RFs
Shingles
what is the most common complication
post herpetic neuralgia
Shingles
complications other than post herpetic neuralgia
herpes zoster opthalmicus
herpes zoster oticus (Ramsay hunt syndrome) - HHV3 infection of the facial nerve
Shingles
what is herpes zoster opthalmicus
a complication.
shingles affecting the ocular division of the trigeminal nerve
Lichen planus
what is it
an autoimmune condition that causes localised chronic inflammation
Lichen planus
describe the rash
itchy, papular rash
polygonal in shape
Wickham’s striae: white lines pattern on the surface
Koebner phenomenon
Lichen planus
where is the rash most common
on the palms, soles, genitalia and flexor surfaces of the arms
Lichen planus
what may be seen in the mouth
white-lace pattern on the buccal mucosa
Lichen planus
nail features
longitudinal ridging (onychorrhexis)
thinning of nail plate
Lichen planus
lichenoid drug eruption causes
- gold
- quinine
- thiazides
Lichen planus
mnx
- potent topical steroids
Lichen planus
mnx for oral lichen planus
benzydamine mouthwash or spray
Actinic Keratoses
what is it
a common premalignant skin lesion that develops as a consequence of chronic sun exposure
pre cursors for SCCs
Actinic Keratoses
RFs
- type I or II skin
- hx of sunburn
- outdoor occupation or hobbies
- immunosuppression
Actinic Keratoses
describe it
thickened papules or plaques w/ surrounding erythematous skin + a keratotic, rough warty surface
Actinic Keratoses
common location
- temple of head
- back of head
Actinic Keratoses
mnx for localised lesions
cryotherapy, curettage or surgical excision
Actinic Keratoses
mnx for larger lesions
- topical S-Fluorouracil (cytotoxic agent)
- topical imiquimod (modifies immune response)
- topical diclofenac (NSAID for mild AK)
Bowen’s disease
what is it
a type of precancerous dematosis that is a precursor to SCC
more common in older patients
Bowen’s disease
features
- irregular, red, scaly plaques
- often 10-15mm
- on sun exposed areas: temple, neck, lower limbs
- slow growing
Bowen’s disease
mnx
- top 5-flurouracil
- top steroids
- cyro, excision
what is the most common form of skin cancer
BCC
Basal Cell Carcinoma
which type of BCC is most common and name some others
most common: nodular superficial pigmented cystic keratotic morphoeic
Basal Cell Carcinoma
presentation of a nodular BCC
- Pearly / shiny nodule with a smooth surface
- small, skin coloured/pink nodule w/ central depression
- surface telangiectasia
- head + neck
Basal Cell Carcinoma
mnx
- surgical excision w/ 4mm margin
- curettage + cautery
- cryo
- top: imiquimod, fluorouracil
- radiotherapy
Squamous Cell Carcinoma
presentation
- irregular ill-defined red nodule
- scale + ulceration
- rapidly growing
Squamous Cell Carcinoma
causes
- UV light
- human wart virus
- burns
- genetic
lead to DNA mutations
Squamous Cell Carcinoma
what makes it a good prognosis
- well differentiated tumour
- <20mm in diameter
- <2mm deep
- no associated diseases
Squamous Cell Carcinoma
what makes a bad prognosis
- poorly differentiated tumours
- > 20mm in diameter
- > 4mm deep
- immunosuppression
Squamous Cell Carcinoma
mnx
- lesion <20mm: surgical excision w/ 4mm margin
- > 20mm: surgical excision w/ 6mm margin
- Mohs micrographic surgery if in cosmetically important sites
Malignant Melanoma
if any lesion has ____, you should refer urgently under 2w wait pathway
Asymmetry Border irregularity Colour variation Diameter >6mm Evolves over time
Malignant Melanoma
what are the types
- superficial spreading
- nodular
- lentigo maligna
- acral lentiginous
Malignant Melanoma
superficial spreading:
- common?
yes 70% of cases
Malignant Melanoma
superficial spreading: typically affects?
- young ppl
- arms, legs, back, chest
Malignant Melanoma
superficial spreading: appearance
- growing moles
- usually grows horizontally first
Malignant Melanoma
dx
- dermatoscope
- excisional biopsy –> histology for dx + establish Breslow thickness
Malignant Melanoma
trx
- wider excision margin around lesion
Malignant Melanoma
trx for stage III + IV (metastatic)
- adjuvant immunotherapy + chemo
Malignant Melanoma
further inx if Breslow Thickness >1mm
sentinal node biopsy (to look for metastases + stage the cancer)
Scabies
cause
by the mite Sarcoptes scabiei
Scabies
pathphysiology
- Sarcoptes scabiei burrows into skin
- lays eggs in the stratum corneum
- 30d later: delayed type 4 hypersensitivity reaction to mites/eggs
- intense puritis
Scabies
features
- widespread pruritis
- linear burrows on hands
- classically worse at night
- excoriation, infection due to scratching
- papular vesicular
Scabies
1st line trx
top permethrin 5%
leave on for 12h before washing off
for 7d
Scabies
2nd line trx
malathion 0.5%
leave on skin for 24h
Scabies
trx for all contacts
all should be treated even if asymptomatic
Tinea
what is it
dermatophyte fungal infections
Tinea
what are the types
- tinea capitis (scalp ringworm)
- tinea corporis (ringworm)
- tinea pedis (athlete’s foot)
- tinea incognita
Tinea
what is tinea corporis (ringworm)
itchy annular lesions with clear, defined, raised, scaly edge
Tinea
what is tinea capitis
Scalp ringworm: Patches broken hair, scaling and inflammation
Tinea
what is tinea pedis
athlete’s foot: Moist scaling and fissuring in toewebs
Tinea
what is tinea incognita
inappropriate treatment of tinea with corticosteroids, causing a different appearance
may occur when rash is wrongly diagnosed as dermatitis initially
Tinea
establish dx with?
skin scraping, swabs or hair/nail clippings
Tinea
mnx
- top antifungal: terbinafine cream, ketoconazole/selenium sulphate shampoo
- PO antifungal: itraconazole, fluconazole
Impetigo
clinical features
- golden crusted lesions around mouth
- pruritic rash
- v. contagious
Impetigo
common cause
staph aureus
strep pyogenes
Impetigo
who is it common in
children
Impetigo
mnx for pts NOT systemically unwell/high risk of complications
hydrogen peroxide 1% cream
Impetigo
mnx
- top fusidic acid
- intranasal mupirocin
- PO flucloxacillin
Impetigo
what should children do about school
exclude from school until lesions are crusted and healed
or 48h after abx trx
Cellulitis & Erysipelas
what is the difference
cellulitis: acute bac infection of dermis + SC tissue
erysipelas: more superficial infection
Cellulitis & Erysipelas
organisms
staph aureus, strep pyogenes
Cellulitis & Erysipelas
presentation
- warmth, pain, erythema, swelling
- blisters may form
- usually lower limb
- generally unilateral
Cellulitis & Erysipelas
inx
- FBC (raised WCC)
- blood culture
- purulent focus culture
- CT/MRI if orbital cellulitis suspected
Cellulitis & Erysipelas
mnx
flucloxacillin PO
Cellulitis & Erysipelas
comlications
- local tissue damage
- sepsis
- orbital cellulitis
well-defined circular papules on which evolve at different stages to form a ‘target-shaped’ lesion of three concentric rings of different colours. The rash starts on the palms/soles and spread up the limbs to the trunk. what is it
erythema multiforme (could be caused by HSV)
what is psoriasis relieved by
exposure to sun
pruritic papulovesicular lesions over the buttocks and extensor surfaces of the arms, legs, and trunk. Diarrhoea for a few months. What could this be
dermatitis herpetiformis (assc w/ coeliac disease)
mnx of pruritic sx of Dermatitis Herpetiformis
Dapsone (an abx)
and a gluten free diet
mnx of staph scalded skin syndrome
IV vancomycin
trx of psoriasis on scalp
3% salicylic acid cream in combination with a tar-containing shampoo.
Pemphigus vulgaris
what is it
an autoimmune disease caused by antibodies directed against desmoglein 3, a cadherin-type epithelial cell adhesion molecule
Pemphigus vulgaris
which molecule is affected by the attacking antibodies
desmoglein 3
Pemphigus vulgaris
which population is commonly affected
Ashkenazi Jewish population
Pemphigus vulgaris
features
- mucosal ulceration
- skin blistering
- flaccid, easily ruptured vesicles and bullae
- typically painful but not itchy
- Nikolsky sign positive
Pemphigus vulgaris
what will biopsy show
acantholysis (loss of coherence between epidermal cells due to the breakdown of intercellular bridges)
Pemphigus vulgaris
mnx
steroids are first-line
immunosuppressants
Bullous pemphigoid
what is it
an autoimmune condition causing sub-epidermal blistering of the skin
Bullous pemphigoid
which proteins are attacked by antibodies
hemidesmosomal proteins BP180 and BP230
Bullous pemphigoid
who is it more common in
elderly patients
Bullous pemphigoid
features
- itchy, tense blisters typically around flexures
- blisters usually heal without scarring
- no mucosal involvement (i.e. the mouth is spared)
Bullous pemphigoid
what will skin biopsy show
immunofluorescence shows IgG and C3 at the dermoepidermal junction
Bullous pemphigoid
mnx
- PO corticosteroids
- topical corticosteroids, immunosuppressants and antibiotics are also used
Bullous pemphigoid
complications
- Bacterial staph + strep skin infection, and sepsis
- Viral infection with herpes simplex, varicella or herpes zoster
- Complications of treatment
Bullous pemphigoid
inx
- Direct immunofluorescence staining of a skin biopsy
- bloods: indirect immunofluorescence test for circulating pemphigoid BP180 antibodies
