erythema multiforme

Question 1

what is it

Answer 1

hypersensitivity reaction triggered by infection or medications causing characteristic target lesions on the skin

Question 2

3 stages

Answer 2

erythema multirome minor

major/SJS one or more mucous membranesw
10% skin

TEN over 30% skin has it

Question 3

triggers

Answer 3

mycoplasma pneumonia
HSV
sulphonamides 
penicillines
phenytoin 
phenobarbitol
bactrim (trimetoprim and  sulfamethoxazole)

Question 4

clinical features

Answer 4

prodrome of URI symptoms

after 24hrs target lesions on hands feet, trunk, elbows, knees face

pruritus

mucosal lesions devevlop after a few days
-eyes: conjunctivitis, uveitis
-lips- swollen and red]
genitals

Question 5

describe target lesions

Answer 5

sharp demarcated macules

turn into elavated papules

enlarge to form plaques

centre is dark red
next ring is pale red
oouter ring is bright red

can become bullous

Question 6

dg

Answer 6

negative nikolsky sign in minor
sjs andd tenss positive
koebnar sign may be present
skin biopsy

Question 7

what does biopsy show in EM

Answer 7

hydropic degen of basal keratinocites

apoptotic keratinocytes

intercellular oedema

epithelian necrosis in SJS/TEN

Question 8

rx of minor

Answer 8

EM minor is self limiting so only antihistamines needed

Question 9

rx of major

Answer 9

IV immunoglobulin
oral anaesthetics
opthalmological rx of eye pain

Question 10

rx for reccurent EM suppression

Answer 10

dapsone
antimalarial - hydroxyquinone
thalidomide