The infection commonly known as zoster is caused by the varicella-zoster virus (VZV), a member of the herpes virus family. Most people infected with VZV are infected as children (when the virus presents as chicken pox). The virus remains dormant within the body, living in the nerve root ganglion. When a person’s immune system is compromised, VZV can reactivate and cause the clinical syndrome known as shingles, which presents as a rash with a dermatomal distribution beginning with pain and developing into a papulovesicular eruption that later scabs and crusts. In some cases, the rash may spread across two or more dermatomes (disseminated varicella), at times encompassing the whole body. While uncommon, disseminated varicella can be seen in patients with HIV and is more serious than the common zoster infection.

Zoster is common among HIV-positive patients, even those with preserved CD4 counts; thus, it is frequently a presenting diagnosis that prompts HIV testing.⁹⁵ Disseminated, recurrent, or chronic zoster, accompanied by neurologic complications, are more common at low CD4 counts. In areas where CD4 counts are not available, these complications should prompt the initiation of PCP prophylaxis. ⁹⁶

Herpes simplex is also more common among HIV-infected patients, presenting as a painful cluster of vesicles. Lesions may be peri-oral or genital. Chronic, ulcerative lesions and frequent recurrence are associated with advanced immunosuppression.⁹⁷

An approach to managing herpes infections is summarized in Protocol 3.21.^98,99