Hailey-Hailey disease successfully treated with photodynamic therapy: Case report.

Hailey-Hailey disease (HHD) is a rare genetic benign condition resulting in blisters predominantly on the skin folds. The inheritance is autosomal dominant with complete penetrance, but a variable expressivity in affected family members. It can be triggered by a vast variety of factors such as sweating, weight gain, infection, trauma, pregnancy, and ultraviolet radiation, but the major cause of the disease is a mutation in the ATP2C1 gene. The lesions are typically distributed symmetrically within intertriginous regions such as the retroarticular folds, axillae, inguinal, and perianal regions and presents as flaccid vesicles and blisters on erythematous skin, giving rise to erosions, fissures, and vegetations. There is no specific therapy for HHD. The therapeutic approach to HHD involves the control of exacerbating factors, secondary infections, and cutaneous inflammation. Because of the rarity of the disease, evidence of efficacy for topical or systemic therapies is mainly based on small observational studies, case reports, and clinical experience. We present a case of HHD successfully treated by photodynamic therapy (PDT) with a topical liposomal chlorin photosensitizer.