Kaposi's varicelliform eruption in mycosis fungoides.

Kaposi's varicelliform eruption, caused by herpes simplex type 1, developed in a patient with mycosis fungoides four days after initiation of photochemotherapy with methoxsalen plus long-wave ultraviolet light (PUVA). He had a history of recurrent localized herpes infection. Vidarabine (adenine arabinoside) was used as treatment. Rechallenge with PUVA did not provoke another herpes infection. Kaposi's varicelliform eruption is rare in mycosis fungoides. Vidarabine may prove to be useful in the treatment of widespread herpes simplex.