• In the immunocompromised host, the clinical manifestations and course of herpes simplex virus (HSV) infection differ in patients with defective cell-mediated immunity, as seen in HIV infection (see Chapters 6, 17, and 28 for a full discussion of HSV infections in immunocompetent hosts).

• Recurrent lesions may affect mucous membranes and possibly become chronic, centrifugally expanding ulcerations. These ulcerations may persist for 1 month or more in an HIV-positive patient and are an AIDS-defining diagnosis.

• Lesions may become resistant to acyclovir, or they may develop into chronic keratotic papules. Because acyclovir resistance is associated with prior treatment of suboptimal doses, it is important not to undertreat HIV-positive patients who also have HSV infections.

• Initially, there are the typical grouped vesicles on an erythematous base, which evolve into pustules, erosions, and crusts.

Ultimately, the following lesions may occur:

• Severe or chronic erosions, ulcerations, or keratotic lesions should alert the clinician to the presence of advanced immunosuppression (Figs. 33.1 and 33.2).

• Mucosal erosions or papules.

• Centrifugally expanding ulcerations with scalloped borders.

• Keratotic or wartlike papules or plaques (Fig. 33.3).

• Lesions may be more severe and more extensive than in immunocompetent hosts.

• See Chapters 6, 17, and 28 for detailed discussion.

• Intraoral areas, including the tongue, buccal mucosa, palate, and gingivae may be involved.

• Chronic ulcerative lesions in perianal areas may occur. These lesions can extend into the intergluteal cleft (see Fig. 33.2).

• Keratotic lesions may occur in any location.