Efficacy of systemic phenytoin in the treatment of junctional epidermolysis bullosa.

Oral phenytoin has been shown to be effective in the treatment of recessive dystrophic epidermolysis bullosa (EB). To determine the possible efficacy of this drug in junctional forms of this disease, we treated four children (two with generalized atrophic benign EB [GABEB] and two with Herlitz disease) with two 16- to 20-week treatment periods with phenytoin separated by an eight- to 12-week drug-free period. Phenytoin was administered to achieve serum levels similar to those previously proved effective in treating recessive dystrophic EB. Serial counts were made of lesions (blisters, crusts, and erosions); surface areas of granulation tissue, when present, were also serially measured. In addition, changes in the percentage of surface area involved with scarring as well as changes in extracutaneous disease activity were similarly assessed. Both patients with GABEB showed excellent response during each course of phenytoin, with average reductions in lesion counts of 70% and 38%. In addition, subjectively, the healing times also appeared to be reduced. During the "wash-out" period, total lesional counts returned toward pretreatment levels. Both patients with GABEB subsequently have received phenytoin for an additional two years off of protocol, with continued excellent response. In contrast, the conditions of both patients with the Herlitz variant worsened while taking phenytoin, with increases in overall lesional counts of 31% and 72%. Also, the surface areas of exuberant granulation tissue either remained unchanged or increased during the course of phenytoin treatment. We conclude that phenytoin is effective in at least some patients with the GABEB subset of junctional EB, whereas no efficacy has been noted in patients with the more severe Herlitz variant.