Eczema herpeticum during treatment of atopic dermatitis with 0.1% tacrolimus ointment

Recent evidence suggests that 0.1% tacrolimus ointment is an effective treatment of atopic dermatitis. Tacrolimus is an immunosuppressive agent that interferes with cell-mediated immunity. We have observed 2 cases of eczema herpeticum among 36 patients with atopic dermatitis treated with a topical preparation containing 0.1% tacrolimus. A 29-year-old male patient developed generalized herpetic lesions on his face on the 4th day of treatment. His SCORAD was then 73, and the tacrolimus blood level was 7.5 ng/ml. A 23-year-old woman developed disseminated herpetic lesions on her neck, face, shoulders and legs during the 9th week of treatment. Her SCORAD was then 41, tacrolimus blood levels were <3 ng/ml 2 weeks before the infection. Herpes simplex virus type 1 antigens were identified in several lesions by direct immunofluorescence in both patients. Neither patient recalled previous episodes of cold sores. The lesions resolved quickly under intravenous acyclovir treatment but resulted in important facial scarring in the male patient.

Eczema herpeticum is a well-known complication of atopic dermatitis. Available data do not allow to link topical tacrolimus with an increased risk for eczema herpeticum, but they are insufficient to exclude an association. Future studies and careful documentation of cases are needed in order to better characterize patients at risk.