A case of radiotherapy-induced bullous pemphigoid with unusually delayed onset: A case report.

Bullous pemphigoid is an auto-immune blistering disease that generally affects older patients. Radiotherapy is one of the many triggering factors that have been described. Time to disease onset is variable; cases have been described during the course of radiotherapy while others have occurred up to 9 years later. We report a case of localized bullous pemphigoid on an irradiated site with unusual late presentation, 25 years after radiotherapy for left breast cancer. The pathophysiology of radiation-induced bullous pemphigoid is not clear, but the concept of an immunocompromised district seems to be a plausible explanation for the delayed onset of the disease.