Abstract: In order to study there lationship between erythema multiforme (EM) and her pessim-plexvirus (HSV),particularly the clinical features and the proportion of the herpes-asociated EM in EM,skin biopsy specimens of typical lesions from 60 patients with EM were examined for the presence of HSV DNA by polymerase chainreaction (PCR).HSV DNA was also examined by PCR in 32 controls including biopsy specimens taken from 16 normal skin and 16 other skin diseases.The results demon-strated that HSV-specific DNA was positivein 21 (35%) patients with EM,while all controls were negative.According to the history of the patients, among 60 cases of EM,5 were drug-associated EM,8 were virus-associated EM,the remains 47 were idiopathic.The study showed that in 21 HSV DNA positive cases,only 2 had herpes labialis preceding the onset of EM;15/21(71.4%) cases presented recurent EM;the onset was mostly in the winter.The idiopathic EM in this group had an association with herpes virus infection in most cases despite the absence of clinicaly apparent HSV in fection.PCR can provide a quick and efective method for detecting HSV in EM lesions and determine the HSV-asociated cases.

Key words: Erythema multiforme, Herpes virus hominis, Polymerase chain reaction