Background An isotopic response is the occurrence of a new skin disease at the site of another unrelated, healed skin disorder.
Methods We report three cases of unilateral granulomatous fungal infection in immunocompetent patients at sites of resolved herpes zoster on the face. Diagnoses were made by potassium hydroxide preparation, histopathologic findings, and fungal culture. Two patients had Candida albicans folliculitis, and the other was infected with both Epidermophyton floccosum and Trichophyton mentagrophytes.
Results The patients responded well to antifungal therapy.
Conclusions Localized isotopic fungal infections, although rare, can occur in immunocompetent patients.