ACYCLOVIR-RESISTANT CHRONIC CUTANEOUS HERPES-SIMPLEX IN WISKOTT-ALDRICH SYNDROME

A 28-year-old man with Wiskott-Aldrich syndrome presented with ulcerat ive-proliferative lesions on his face from which herpes simplex type 1 (HSV-1) was isolated. He was initially treated with 10 mg/kg of acycl ovir (Zovirax(R)) intravenously every 8 h, but his skin lesions worsen ed. Clinical resistance to acyclovir was suspected, and therapy with t his drug was intensified. The dosage of acyclovir was increased to 45 mg/kg, administered by continuous infusion, and the lesions subsequent ly resolved. The strain of HSV recovered from the patient showed acycl ovir-resistance in vitro, using the colorimetric method with neutral r ed. Herpes simplex virus resistance to acyclovir is rare. It is more c ommon in immunocompromised patients if subtherapeutic doses are admini stered in the treatment of chronic persistent forms of infection. When ever clinical resistance to acyclovir is suspected, the dosage should be increased to 2 mg/kg per h administered via an infusion pump. If no improvement is observed in the patient's condition with this regimen, a phosphorylated medication whose mechanism of action is not dependen t on viral thymidine kinase, such as foscarnet (phosphonoformic acid), should be substituted.