On previous reports about the relationship between herpes simplex virus(HSV) & erythema multiforme(EM), subjective specimens were taken from target lesions and papules of herpes-associated EM or recurrent EM of unknown etiology. PCR-positive specimen were found in target lesion of idiopathic EM and even drug induced EM. But biopsy was actually performed when the clinical finding is atypical and so diagnosis is not certain with only clinical finding. In non-classic type of erythema multiforme without herpes associated history or recurrent episode, we try to evaluate the clinical and histopathologic findings and to detect the DNA of herpes simplex virus.

We clinically and histopathologically observed the 29 cases of non-classic type of erythema multiforme through the clinical photographics, clinical charts and telephone visiting. And we also tested 29 paraffin-embedded tissues from non-classic type of erythema multiforme by PCR with two nested primer pairs.

The results are as follows :

1) There are not specific difference according to age and sex.

2) The most frequent clinical type was the diffuse type(55.2%), followed by the acral type(24.1%) and central type(20.7%).

3) The major cause was idiopathic(72.4%), followed by the drug(27.6%).

4) There were various findings in clinical manifestation, including maculopatch, palulopla-que, wheal-like papule, vesicle-bullae, purpuric macule and papule and urticaria.

5) Histologically, we observed necrotic keratinocyte(48.3%) and spongiosis, exocytosis and vacuolization of basal cell in most cases. Eosinophilic infiltration, pigmentary incontinence and RBC extravasation were also seen.

6) The HSV positive specimens were fund in 2 cases(6.9%).

Although herpes simplex virus infection is a major contributing factor to most cases of erythema multiforme, our data supports the finding that it is not so important in non-classic type of erythema multiforme.