Investigate the causes and characteristics features of erythema multiform at The National Hospital of Dermatology and Venereology. Objectives: To investigate the features of erythema multiform associated with herpes simplex virus or drugs at the National Hospital of Dermatology and venereology (NHDV). Materials and Methods: a prospective study basing on 41 patients with erythema multiform. PCR with HSV and drugs reaction tests were realised. Results: 8/41patients (19,5 percent) were HSV(+),in which 17,1 percent of patients suffering major type, 2,4 percent with minor type. There was 9/41 patients (22 percent) related with drugs. In which 14,6 percent present major and 7,3 percent with minor type (p 0,05
Fisher' exact test). The reoccurence was 26,8 percent of patients., The reoccurence of patients asociated with HSV (13,5 percent) was nearly trifoled to the drugs group (4,9) percent
12,2 percent of patients with HSV(+) present cutaneous manifestations more emerge from normal skin area than ttiat of group with drug reaction. There was not difference between 2 groups about pre-syndrome. Conclusions: one fifth of patients associated with HSV, 22 percent of patients related to drugs. The patient with HSV+ suffering the minor type and most of drug-related patients was major type. The lesion in patients with HSV(+) was more emerged than that related to drugs.