Erythema multiforme

Question 1

what is it?

Answer 1

a hypersensitivity reaction that is most commonly triggered by infections.

Question 2

what is it divided into?

Answer 2

minor form

major form

Question 3

features

Answer 3

target lesions

initially seen on the back of the hands / feet before spreading to the torso

upper limbs are more commonly affected than the lower limbs

pruritus is occasionally seen and is usually mild

Question 4

features

Answer 4

target lesions

initially seen on the back of the hands / feet before spreading to the torso

upper limbs are more commonly affected than the lower limbs

pruritus is occasionally seen and is usually mild

Question 5

causes (x7)

Answer 5

viruses: herpes simplex virus (the most common cause), Orf*- a skin disease of sheep and goats caused by a parapox virus

idiopathic

bacteria: Mycoplasma, Streptococcus

drugs: penicillin, sulphonamides, carbamazepine, allopurinol, NSAIDs, oral contraceptive pill, nevirapine

connective tissue disease e.g. Systemic lupus erythematosus

sarcoidosis

malignancy

Question 6

what is erythema multiforme major?

Answer 6

The more severe form, erythema multiforme major is associated with mucosal involvement