A double-blind, placebo-controlled trial of continuous acyclovir therapy in recurrent erythema multiforme.

Twenty patients who suffered from more than four attacks of erythema multiforme (EM) per year were enrolled in a 6-month double-blind, placebo-controlled trial of acyclovir 400 mg twice daily. Fifteen patients had disease precipitated by recurrent herpes simplex. In the acyclovir-treated group the median number of EM attacks during the treatment period was zero, compared with three in the placebo-treated group (P < 0.0005, Wilcoxon rank sum test). Seven of the 11 patients treated with continuous acyclovir did not have any attacks of EM while taking the drug, and one showed almost complete disease suppression. Following treatment with acyclovir, two patients went into complete remission, whereas all individuals in the placebo group continued to have attacks. In the acyclovir-treated group nine of the 11 patients had herpes simplex-precipitated disease. One of the two patients with idiopathic disease showed complete disease suppression while on acyclovir, lending support to the view that idiopathic recurrent EM may be related to subclinical herpetic infection. In this study, we have shown that continuous acyclovir therapy can completely suppress attacks of recurrent EM and, in some cases, may induce disease remission.