ACROSYRINGEAL CONCENTRATION OF NECROTIC KERATINOCYTES IN ERYTHEMA MULTIFORME - A CLUE TO DRUG ETIOLOGY - CLINICOPATHOLOGICAL REVIEW OF 29 CASES

Erythema multiforme (EM) is caused by various insults, frequently an i nfectious agent or a drug. It is current practice that histologic iden tification of the precipitating factor is not possible. Mie have obser ved a pattern of acrosyringeal concentration of keratinocyte necrosis in certain cases of EM. and retrospectively studied 29 consecutive cas es of EM to establish clinicopathologic correlation for this finding. Acrosyringeal concentration was observed in 10 of 29 specimens, all 10 clinically drug related (Group 1). Nineteen specimens lacked this pat tern (Group 2) of which 3 cases were clinically drug related (sensitiv ity= 0.8, specificity= 1.0). Eosinophils were present in the dermal in filtrate of 6 specimens from Group 1 and 2 specimens from Group 2 (p=0 .025). Acrosyringeal concentration of keratinocyte necrosis in EM occu rs in drug-related cases and is more likely to be accompanied by a der mal inflammatory infiltrate containing eosinophils. Drug concentration in sweat may explain this pattern with subsequent toxic and immunolog ic mechanisms leading to the fully evolved lesion.