Erythema Multiforme Flashcards
what is erythema multiforme
sepctrum disorder
self limiting vesiculobullous disease affecting the skin and/or mucosa
epidemiology of erythema multiforme
mainly affects young adult males
aetiology of erythema multiforme
most common precipitating event = HSV infection
other infections - candida, EBV
drug induced - carbamazepine, tetracyclines
pathogenesis of erythema multiforme
not fully understood
formation of immune complexes which trigger a type III (infection) or type IV (drug induced) hypersensitivity reaction
clinical features of cutaneous EM
characteristic ‘target’ lesion - 3 concentric rings with a well defined border, inner part may be covered by a blister
hands and feet are commonly affected
mucosal features of EM
haemorrhagic crusting of lips
extensive bullous lesions with rapidly rupture to form painful erosions
occular involvement can lead to scarring and blindness
how long does EM usually last
2 weeks
but may recurr
EM minor
target lesions on extremities
rarely affects mucosa
(<10% BSA, -ve Nikolskys sign)
EM major
skin and >=2 mucosal sites
usually those with HIV infection
(<10% BSA, -ve Nikolskys sign)
steven johnson syndrome
extreme form of EM
<10% BSA skin affected
positive nikolskys sign
toxic epidermal necrolysis
> 30% BSA
positive nikolskys sign
25-30% mortality rate
treatment of mild EM
symptomatic relief
topical corticosteroids
oral - betamethasone MW (1x 500mcg tablet in water, 4x day)
skin lesions - fluocinonide
treatment of severe EM
systemic steroid - prednisolone
may also need IV fluids etc if unable to ingest food
treatment of recurrent EM
long term aciclovir
long term immunosuppresive therapy e.g azathioprine
