Dermatology Flashcards
What is urticaria?
Local increase in permeability of capillaries and small venules
Histamine release causes itchy wheals
What is angioedema?
Deeper swelling involving the dermis and subcutaneous tissues
Swelling of tongue and lips
What is anaphylaxis?
Bronchospasm, facial and laryngeal oedema and hypotension
What is erythema nodosum?
Hypersensitivity reaction causing discrete tender nodules that may become confluent usually on shins
Occur with Group A beta haemolytic strep
TB, pregnancy, sarcoidosis, IBD, chlamydia
What is erythema multiforme?
Acute self-limiting condition
Mucosa not involved or limited to one surface
What are the features of Stevens-Johnson syndrome?
Mucotaneous necrosis with 2 or more mucosal surfaces involved
Skin involved may be extensive or limited
What are the features of toxic epidermal necrosis?
Usually drug induced
Extensive skin and mucosal necrosis and system toxicity
Full thickness epidermal necrosis
Leads to sepsis, electrolyte imbalance and multi system organ failure
What are the features of erythroderma?
Exfoliative dermatitis involving over 90% of skin surface
Skin is inflamed, oedematous and scaly
Systemically unwell - lymphadenopathy and malaise
What are some causes of erythroderma?
Eczema, psoriasis
Lymphoma
Sulfonyureas, penicillin, allopurinol
What are the features of eczema herpeticum?
Widespread eruption of crusted papules, blisters and erosions due to herpes simplex
Fever and malaise
What are some complications of eczema herpeticum?
Herpes hepatitis, encephalitis, DIC
What is erysipelas?
Acute superficial form of cellulitis - well-defined red border
What are the commonest organisms in cellulitis?
Streptococcus pyogenes
Staphylococcus aureus
What are the features of staphylococcal scalded skin?
Production of circulating epidermolytic toxin
Develops in a few hours - days
Scald appearance –> large flaccid bulla –> perineal crusting
Very painful
What is pityriasis?
Scaly pale brown patches on upper trunk that fail to tan
What are some clinical features of basal cell carcinomas?
Usually nodular Small skin coloured papule Surface telangiectasia Rolled edge Ulcerated centre
What are some treatments for basal cell carcinomas?
Surgical excision
Radiotherapy
Imiquimod cream
What are some clinical features of squamous cell carcinomas (skin)?
Keratoic ill-defined nodules
Locally invasive, can metastasise
What are some features that suggest malignant melanoma?
Asymmetrical Border irregularity Colour irregularity Diameter >6mm Evolution - change in size/shape Symptoms - bleeding/itching
What are some treatments for mild acne?
Benzoyl peroxide
Topical antibiotics
Topical retinoids
What are some treatments for moderate acne?
Oral antibiotics
Anti-androgens
What are some complications of acne?
Hyperpigmentation
Scarring
Deformity
What are some clinical features of acne?
Inflammatory disease of pilosebaceous follicles
Non-inflammatory lesions, open and closed comedones
What are some different types of psoriasis?
Chronic plaque - most common
Guttae - raindrop lesions
Seborrhoeic - naso-labial and retro-auricular
Pustular - palmar-plantar
What are some different patterns of psoriatic arthropathy?
Symmetrical poly arthritis
Spondylosis
Arthritis mutilans
Dactylitis
What are some clinical features of bullous pemphigoid?
Tense fluid filled blisters on an erythematous base - trunk and limbs
Usually affects the elderly
Autoantibodies against antigens between dermis and epidermis
What are some clinical features of pemphigus impetigo?
Flaccid easily ruptured blisters forming erosions and crusts - affects mucosal areas
Often middle-aged
What are some features of venous ulcers?
Painful
Malleolar area
Large, shallow, irregular
Warm skin, pulses present, normal ABPI
What are some features of arterial ulcers?
Painful, especially at night
Pressure areas
Small, defined, deep, necrotic base
Cold skin, absent pulse, ABPI<0.8
What are some features of neuropathic ulcers?
Painless, abnormal sensation
Pressure areas
Over calluses
Warm skin, pulses present, peripheral neuropathy
What are some features of lichen planus?
Itchy flat topped papules symmetrical distribution
Lacey white streaks
Forearms, wrists, legs
What are some differentials for purpura?
Meningococcal septicaemia
DIC
Vasculitis
Senile purpura
What are some clinical features of DIC?
Trauma, sepsis, cancer, CLF
Spontaneous bleeding - ENT, GI, respiratory
What are some clinical features of vasculitis purpura?
Painful lesions
Legs, buttocks, flanks
What are some clinical features of senile purpura?
Elderly, sun damage
On extensors
Systemically well
What are some side effects of retinoids?
Dry skin, lips and eyes
Abnormal LFTs and lipids
Teratogenic
