Four patients with HIV infection and severe immunodeficiency are described who developed atypical varicella zoster lesions. Three of the patients presented with chronic varicella zoster lesions. In two of them such lesions were hyperkeratotic. All three patients had been treated initially with subtherapeutic doses of acyclovir. In one of the patients the lesions were clinically resistant to high dose acyclovir treatment and disappeared only when renal insufficiency developed during foscarnet-famcyclovir treatment. One patient developed a disseminated varicella zoster infection.