Tinea corporis overlying post-herpetic neuralgia: a novel manifestation of wolf’s isotopic response

Abstract

Wolf’s isotopic response is characterized by the occurrence of a new dermatosis at the site of a previously healed and unrelated skin disorder, most commonly following herpes zoster. A wide spectrum of secondary dermatoses has been described, including granulomatous, lichenoid, autoimmune, and neoplastic conditions. However, infectious etiologies-particularly superficial fungal infections-are exceedingly rare in this setting. We report the case of a 58-year-old female who developed tinea corporis localized strictly to the same dermatome previously affected by herpes zoster and persistent post-herpetic neuralgia. Clinical examination revealed an annular erythematous scaly plaque over the left T11 dermatome, corresponding to the healed zoster site. Potassium hydroxide examination demonstrated septate branching hyphae, confirming dermatophytosis. The strict dermatomal localization, along with the temporal sequence of events, supports the diagnosis of Wolf’s isotopic response. To the best of our knowledge, this is the first reported case of dermatophytosis occurring over a site affected by post-herpetic neuralgia. This case highlights the role of persistent neuroimmune dysregulation in creating a localized area of immune vulnerability, predisposing to secondary infections.