Recurrent erythema multiforme (REM) is a mucocutaneous disorder induced by recurrent herpes simplex virus (HSV) infection in 70% of cases.1 Herpes simplex virus genome was detected using the polymerase chain reaction in active REM lesions and in pigmented marks several weeks after healing of the lesions.2 Preventive treatment with oral acyclovir, usually 400 mg twice per day, completely suppresses REM attacks in most patients.3 It is not clear whether failures of acyclovir are related to viral resistance to acyclovir or to non-HSV–induced REM. For the first time, we report a case of postherpetic REM resistant to continuous acyclovir treatment but responsive to the new drug valacyclovir hydrochloride.
Kerob D, Assier-Bonnet H, Esnault-Gelly P, Blanc F, Saiag P. Recurrent Erythema Multiforme Unresponsive to Acyclovir Prophylaxis and Responsive to Valacyclovir Continuous Therapy. Arch Dermatol. 1998;134(7):876-877. doi: