Isomorphic and Isotopic Phenomenon Occurring Simultaneously in a Case of Granuloma Annulare

In the 2009 case report, a 65-year-old male patient with generalized annular skin lesions was diagnosed with granuloma annulare and experienced an isotopic response, where new skin disorders occur at the site of a healed unrelated skin disease, as well as an isomorphic response, where skin lesions of an existing dermatosis appear at sites of injury. The patient's skin lesions initially responded to systemic steroids but relapsed upon withdrawal. After an episode of herpes zoster, the lesions exacerbated, particularly over the healed zoster scars, and responded again to a low dose of prednisolone. The case was notable for the simultaneous occurrence of isotopic and isomorphic responses, suggesting a possible common etiopathogenesis, potentially involving neuropeptides. The patient continued on regular follow-up. The document also briefly mentions two cases of finasteride-induced gynecomastia in patients taking the drug for male pattern hair loss.