erythema multiform

Question 1

definition of erythema multiform

Answer 1

an acute hypersensitivity reaction of the skin and mucous membranes

stevens-johnson syndrome is a severe form with bullous lesions and necrotic ulcers

Question 2

aetiology of erythema multiform

Answer 2

degeneration of basal epidemal cells and development of vesicles between the cells and the underlying basement membrane

lymphocytic infiltrate is seen around the bv adn at the dermal-epidemal junction

immune complex deposition is variable and non-specific

precipitating factor identified in 50% of cases

drugs

infection

inflammation

malignancy

radiotherapy

collagen disorders

Question 3

drugs that cause erythema multiform

Answer 3

sulphonamides

penicillin

phenytoin

barbituates

NSAIDs

allopurinol

anticonvulsants

Question 4

infections that cause erythema nodosum

Answer 4

• viral
  
  • HSV
  • EBV
  • coxsackie
  • adenovirus
  • ORF
  • cytomegalovirus
• bacterial
  
  • mycoplasma pneumoniae
  • chlamydiae
• fungal
  
  • histoplasmosis

Question 5

inflammatory causes of erythema nodosum

Answer 5

RA

SLE

sarcoidosis

UC

systemic vasculitis

Question 6

malignancy causes of erythema nodosum

Answer 6

any age - most commonly children and young adults

female more

Question 7

sx of erythema multiform

Answer 7

non-specific prodromal s of URTI

sudden appearance of itching/burning/painful skin lesions

lesions may fade - leaving behind pigmentation

Question 8

signs of erythema multiform

Answer 8

classic target ‘bull’s eye’ lesions, with a rim of erythema surrounding pale area

vesicles/bullaae

urticarial plaques

lesions are symmetrical, sistributed over arms and legs including the palms, soles and extensor surfaces

Question 9

signs of stevens-johnson syndrome

Answer 9

affecting >2 mucous membranes - conjunctiva, cornea, lips (haemorrhagic crusts), mouth, genitalia

systemic - sore throat, cough, fever, headache, myalgia, arthralgia, diarrhoea, vomiting

shock - hypotn, tachycardia

Question 10

Ix for erythema multiform

Answer 10

not usually needed - clinical dx

determine the preciptating factor

• blood
  
  • high WCC, eosinophils, ESR, CRP
  • throat swab
  • serology
  • albumin low in extensive exudation
  • high urea - result of catabolic state and dehydration
  • autoAb
• imaging
  
  • CXR - to exclude sarcoidosis and atypical pneumonias
• skin biopsy
  
  • histology and direct immunofluorescence may be indicated if in doubt

Question 11

summarise stevens-johnson syndrome

Answer 11

severe form of erythema multiform

variant of toxic epidermal necrolysis

hypersensitivity rn to drugs (salicyclates, sulfonamides, penicillin, barbituates, carbamazepine, phenytoin), infections, cancer

ulceration of skin and mucosal surfaces

target lesions on palms/soles with blistering in centre

prodromal phase - fever, malaise, arthralgia, myalgia +- vomiting and diarrhoea

Question 12

minor form of erythema multiform

Answer 12

erythematous well-defined round lesions on extenser surfaces of peripheries, palms and soles - evolve at different stages into pathopneumonic target lesions

minimal mucosal involvement

Question 13

major form of erythema multiform

Answer 13

associated systemic upset and severe mucosal involvement