Dermatology Flashcards
Which layer of the skin are melanocytes in ?
Epidermis
Functions of the skin ?
- barrier against infection, chemicals and radiation
- fluid balance
- temperature control
- hormonal e.g. Vit D
- immunological
Consequences of skin failure ?
- insufficient temperature
- malabsorption
- fluid loss
- infection
- death
Causes of skin failure
- erythroderma
- drug reactions- toxic epidermal necrolysis
- erythema multiforme (stevens-Johnson syndrome)
- pustular psoriasis
- lupus
Define macule
Small flat lesion without elevation or depression e.g. Freckle
A small (
Papule e.g. Xanthoma
Define patch (derm)
Larger, flat area of altered colour or texture e.g. Vascular malformation- naevus flammeus (port wine stain)
A solid raised skin lesion, >0.5cm in diameter , with a deeper component is known as what ?
Nodule
Define plaque
Palpable scaling raised lesion >0.5cm e.g. Psoriasis
Define vesicle ?
Raised, clear fluid filled lesion
Define bulla
Raised, clear fluid filled lesion >0.5cm e.g. Reaction to insect bite
Pus containing lesion
Pustule e.g. Acne
What is an abscess?
Localised accumulation of pus in dermis or subcut tissue
What is a wheal ?. (Derm)
Transient raised lesion due to dermal oedema e.g. Urticaria/hives
What is a boil/furuncle?
Staphlococcal infection around or within hair follicle
What is meant by discrete vs confluent lesions of the skin?
- discrete = separate, confluent = merging
What is the name for multiple boils/furuncles?
Carbuncle
Define excoriation?
Loss of epidermis following trauma e.g. Scratching in eczema
What is hypertrichosis ?
Non-androgen dependent pattern of excessive hair growth e.g. In pigmented naevi
Classic appearance of psoriasis ?
- Well defined, Salmon pink, erythematous, flaky, crusty patches of skin covered with silver scales
- can be anywhere, but usually on the extensor surfaces and symmetrical
What age does psoriasis usually develop ?
16-22
Triggers for psoriasis ?
- injury to skin
- alcohol
- smoking
- stress
- drugs e.g. Lithium, antimalarials, ibuprofen, ACEi
- throat infections (guttate psoriasis after strep throat)
Pharmacological treatment of psoriasis ?
- acitretin = retinoid (vit A)
- ciclosporin = immunosuppressant (severe psoriasis)
- methotrexate - slows down the rapid division of cells and reduces inflammation (alters immune system)
- hydroxycarbamide = slows rapid division of skin cells
- rotational therapy of all these
Non pharmacological therapy for psoriasis ?
- phototherapy - UVB or PUVA
- emollients
- vitamin D analogues
Presentation of eczema ?
- characterised by papules and vesicles on an erythematous base
- usually on extensor surfaces & face in adults
- flexor surfaces in children
- itchy, erythematous, dry scaly patches
- acute lesions can be vesicular and weepy
- scratching -> excoriation and lichenification
- nails = pitting and ridging
Exacerbating factors for eczema ?
- infections
- allergens (chemicals, food, dust)
- sweating
- heat
- stress
Management of eczema
- avoid exacerbating factors
- frequent emollient +/- bandages and bath oil/soap substitute topical therapies
- topical steroids for flare ups
- topical immunomodulators (e.g. Tacrolimus) as steroid sparing agents
- antihistamine for symptom relief
- phototherapy and immunosuppressants for severe cases
Complications of eczema?
- secondary bacterial infections (crusted weepy lesions)
secondary viral infection: - molluscum contagiosum (pearly papules with central umbilication)
- viral warts
- eczema herpeticum
What is acne vulgaris?
Inflammatory disease of the pilosebaceous follicle
Aetiology and contributing factors to acne vulgaris ?
Hormonal(androgen) Contributing: - increased sebum production - abnormal follicular keratinisation - bacterial colonisation (proprionibacterium acne) - inflammation
Presentation of acne vulgaris ?
- non inflammatory lesions (mild acne) = open and closed comedones
- inflammatory lesions (mod-severe) = papules, pustules, nodules, cysts
- commonly affects face, chest and upper back
Management of acne vulgaris ?
- avoid food that triggers break outs
- topical: benzoyl peroxide, antibiotics, retinoids
- oral: antibiotics, anti-androgen, oral retinoids
Complications of acne vulgaris
- post inflammatory hyperpigmentation
- scarring
- deformity
- psychological/social effects
What is a basal cell carcinoma ?
- Slow growing, locally invasive malignant tumour of the epidermal keratinocytes
- rarely metastasises
Presentation of basal cell carcinoma ?
- can be: nodular, plaque-like (superficial), cystic, morphoeic (sclerosing), keratotic or pigmented
- small skin coloured papule/nodule with surface telangiectasia & pearly rolled edge
- lesion may have necrotic or ulcerated centre
- most commonly on head and neck
Management of basal cell carcinoma ?
- Surgical excision
- radiotherapy when excision not appropriate
- topical imiquimod cream
Which type of eczema usually presents in infancy and resolves in teenage years ?
Atopic
What is the appearance of pomphylox eczema ?
Blisters on hands and feet
What is stasis eczema ?.
Dermatitis as a result of blood pooling e.g. In the leg from insufficient venous return
Differences between allergic and irritant dermatitis ?
- allergic: appears a few days after exposure and is more localised
- irritant: appears immediately and is more likely to be widespread
Which is more likely to metastasise, basal cell or squamous cell carcinoma ?
Squamous cell
Risk factors of squamous cell carcinoma
- UV exposure
- pre malignant conditions e.g. Actinic keratoses
- chronic inflammation e.g. Leg ulcers, wound scars
- immunosupression and genetic predisposition
Presentation of squamous cell carcinoma ?
Keratotic (scaly and crusty), I’ll defined, nodule which may ulcerate
Risk factors for malignant melanoma
- UV
- skin type I
- history of multiple moles/ atypical moles
- fam hist
- previous Melanoma
Presentation of malignant melanoma?
ABCDE symptom rules:
Asymmetrical shape Border irregularity Colour irregularity Diameter >7mm Evolution of lesion (change in size/shape)
*bleeding and itching
How do lentigo malignant melanoma present in ?
Common on the face of elderly people
How do superficial spreading and nodular melanomas present ?
In young and middle aged people
Superficial = lower limb
Nodular = trunk
What is urticaria ?
- aka hives
- pale, red, raised, itchy bumps
- may cause burning or stinging
- usually due to allergic reaction
Symptoms of rosacea ?
- flushing
- persistent facial redness
- telangectasia
- papules and pustules
- dry peeling skin
- dry gritty eyes
- thickened skin
Treatments for rosacea
- metronidazole or azelaic acid creams
- oral abx: tetracycline, doxycycline, erythromycin
- briminidine tartrate - gel to treat flushing
- clonidine (relaxes blood vessels), b-blocker
- laser
What are seborrhoeic warts ?
Benign, hyperkeratotic skin lesions associated with ageing
Visual appearance of seborrhoeic warts
.
- flat topped, warty-looking lesion
- appears ‘stuck on’ to the skin
- usually pigmented, pale-black
- well circumscribed border
When would you be suspicious that a lipoma is infarct a malignant liposarcoma ?
- > 5cm
- located in extremities, retroperitoneally, groin, scrotum, abdo wall
- deep (beneath or fixed to fascia)
- malignant behaviour e.g. Rapid growth, invasion of bone or nerve
Presentation of lipoma
usually non-painful, round, mobile, soft doughy mass with normal skin overlying
Presentation of Epidermoid cysts
- painless, round, firm skin lump
- may discharge foul cheese-like discharge
- can become infected, red and inflamed
- flesh, yellow or white coloured
Sites most commonly affected by Epidermoid cysts ?
- face
- trunk
- neck
- extremities
- scalp
What are dermofibromas
Benign skin tumours
Presentation of dermofibromas
- usually single nodules that develop on extremity, most commonly lower leg
- mobile, firm-hard (feel like small lentil under skin)
- overlying skin may be dimpled or smooth
- can be skin coloured or pink
- after initial growth remain static
What are Campbell de morgan spots?
- aka cherry haemangiomas
- benign skin lesions of Middle age+ due to proliferating dilated capillaries
- non-blanching
Presentation of Campbell de morgan spots
- usually occur over trunk and extremities
- any skin site other than mucous membranes
- bright cherry red, non blanching lesions
- widespread in the elderly
What are fibroepithelial polyps?
- skin tags
- pedunculated, skin coloured/brown papules
- commonly forming at skin folds e.g. Neck, axillary, groin
Which layer of the skin are all the blood vessels in ?
Dermis
What is intertrigo ?
Inflammation of the body folds
- usually due to the chafing of warm moist skin - usually in the overweight
- appears red and sore looking, may ooze or itch
What are tinea infections ?
Fungal infections caused by dermatophytes (grip of fungi that invade and ow in dead keratin)
Common organisms causing tinea infections?
- Trichophytons rubrum, tonsurans etc
- microsporum canis
- epidermophyton
Presentation of tinea infections
- itching, Radha no nail discolouration
- hair loss in tinea capitus
- common in those who play contact sport
Complications of tinea infections ?
- cellulitis
- impetigo
What is pityriasis vesicolour ?
Skin condition where flaky discoloured patches appear, mainly on chest and back
What causes pityriasis vesicolour?
- Proliferation of lipophilic yeast, malassezia furfur (aka pityrosporum orbiculare in its yeast-like form)
- is part of normal flora of skin
Presentation of pityriasis vesicolour
- insidious onset
- macular lesions and patches of altered pigment
- superficial scale, best seen my scrapping lesion with finger nail
- not contagious
What is the name of the organism causing scabies?
Sarcoptes scabiei (mite)
Presentation of scabies
- Widespread itching, worse at night and when warm
- track marks
- papules, vesicles, pustules, nodules
Treatment for scabies
permethrin 5% dermal cream
Which conditions are dermatological emergencies ?
- drug eruptions
- erythroderma
- erythema multiforme/SJS/TEN
- urticaria & angioedema
Features of drug eruption
- facial/mucous membrane involvement
- widespread erythema
- skin pain
- blistering
- fever
- lymphadenopathy/arthralgia
- shock
What is morbilliform ?
- Rash resembling measles
- due to drug eruption
What is acute generalised exanthematous pustulosis?
- rapid onset drug eruption (2d) lasting for 1-2 weeks
- starts in flexures and face
- erythema with widespread pustules
- neutrophil leucocytosis
What is drug hypersensitivity syndrome ?
- drug reaction with eosinophilia and systemic symptoms
- severe reaction 2-8 weeks after drug initiation
- wide spread Mac-pac rash with pustules
- can have multi organ involvement
General treatment for most drug eruptions ?
- antihistamine
- emollient
- topical steroid
Presentation of erythroderma
- inflammation of entire skin surface
- pruritis
- hair loss
- hyperkeratosis
- exfoliating dermatitis
- lymphadenopathy
Causes of erythroderma?
- Drug reactions
- dermatitis
- psoriasis
- immunobullous disorders
- cutaneous T cell lymphoma
- HIV
- systemic malignancy
What type of hypersensitivity reaction is erythema multiforme ?
4 - presents with eruption of 3 zoned target lesions (mild)
Clinical features of erythema multiforme ?
- prodromal flu-like symptoms
- acral rash consisting of target lesions
- spreads symmetrically and proximally
- may koerbnerise (skin lesions appearing at site of injury)
Presentation of TEN/Stevens-Johnson syndrome?
- widespread blisters mostly on face or trunk
- erythematous or pruritic macule a
- mucous membrane involvement
- epidermal detachment
What type of hypersensitivity reaction is urticaria and angioedema ?
Type I
Presentation of lichen planus
Itchy eruption of plaques:
- shiny
- purple
- polygonal
- flat topped
- wickhams striae
- wrists and ankles
