Postherpetic isotopic responses with 3 simultaneously occurring reactions following herpes zoster.

Inflammatory, infectious, and neoplastic processes can all occur in prior areas of herpes infection (postherpetic isotopic response [PHIR]). Postzoster granulomatous dermatitis is among the most frequently encountered PHIR, but the exact pathogenesis has not been fully elucidated. Rarely, multiple diseases manifest concurrently in a PHIR. We report a case of cutaneous chronic lymphocytic leukemia (CLL) with an associated granulomatous dermatitis and medium-vessel vasculitis occurring simultaneously at the site of prior herpes zoster. Clinicians and dermatopathologists should be aware of the multiplicity of postzoster isotopic responses and should consider the possibility of multiple diseases manifesting in the same clinical lesion in this setting.