Erythema Multiforme Flashcards
What is Erythema Multiforme?
Type 4 hypersensitivity reactive typically from infection eg HERPES simplex, sometimes MYCOPLASMA pneumoniae, can be drugs
Resolves itself in a few weeks (2 or maybe 6) without specific intervention. Does not leave scarring (may leave mottling / discolouration).
May have target lesions
If eye are affected it can lead to blindness.
Minor and major types (major affect mucous membranes).
Can be difficult to differentiate from SJS (EM does not progress to SJS)
Epidemiology and aetiology of Erythema Multiforme?
- common in young adults 20-40yrs but can be any age
- M>F
- genetic predispostion
- can be recurrent
- 90% are due to infection
Infection:
- HSV typically type 1 (mouth and lips)
- HSV2 infection 2-14days before EM
- Mycoplasma pneumoniae
- many others:
- parvovirus
- herpes zoster
- HIV
- CMV
- viral vaccines
- fungal infection (rare)
How can Erythema Multiforme present?
Preceding symptoms include:
- fever
- joint aches
- muscle weakness
SKIN LESIONS
- lesions many sizes and shapes (MULTIFORME)
- a handful to hundreds
- appear within 24hr period
- start on back of hands and top of feet
- spread towards and include trunk
- upper limbs more common
- palms and soles, face and neck may be involved
- itchy
- mucous membranes may become involved later
Lesions are:
- well dermacated
- round
- red
- initially flat, then become raised
- up to several cm diameter
- evolve of 72hrs
- TARGET LESION; pale middle, red outer edge
Diagnosis of erythema multiforme?
Clinical diagnosis
Maybe get some:
- FBC, U&E
- HSV serology
- rapid PCR
Management of Erythema Multiforme?
- usually self limiting
- topical / oral corticosteroids - sterile dressing
- analgesia
- oral antiviral if HSV
- macrolide or doxycycline if pneumonia
- analgesic mouthwash if painful oral lesion
- antihistamine for itch
Eye involvement, refer to ophtho.
Recurrent EM:
- 6 months continuous antivirals
- consider: DAPSONE, HYDROXYCHLOROQUINE, AZOTHIOPRINE, CYCLOSPORIN
