This infection is caused by reactivationof varicella-zoster virus (VZV),which may remain latent in thedorsal root and cranial nerve gangliafor decades. Reactivation oftenoccurs for no apparent reason, althoughstress and immunosuppressionmay increase the risk.
HSV infections, which appear as grouped vesicles on an erythematous base, are less common in healthy elderly patients than in younger ones. HSV-1 causes herpetic stomatitis, herpes labialis (A), herpetic keratoconjunctivitis, and encephalitis. HSV-2 causes genital herpes, genital erosions (B), and systemic infections in immunocompromised patients.
HSV infections may affect elderly patients with leukemia and lymphoma. These infections, called Kaposi varicelliform eruptions, appear as large areas covered by vesiculopustules and crusts. The infections are of particular concern when they spread to skin whose integrity is undermined by xerosis or eczema.
Bullous pemphigoid also presents with vesicles, but they are not grouped, are larger, and do not contain giant cells on biopsy or Tzanck preparation. Darier disease (keratosis follicularis) can also manifest with widespread crusted papules, vesicles, and plaques; culture and biopsy helps make the diagnosis. HSV infections may spread into the skin of elderly persons affected by bullous pemphigoid, Grover disease, or Darier disease. In elderly and debilitated patients, HSV infection can result in refractory flat sacral or perioral ulcers with peripheral blisters.