Bullous pemphigoid: Etiology, pathogenesis, and inducing factors: Facts and controversies

The intervention of inducing factors in BP can be identified in no more than 15% of patients. Facilitating factors in genetically predisposed individuals are various (drug intake, physical agents, and viral infections). Drugs may act as triggers by either modifying the immune response or altering the antigenic properties of the epidermal basement membrane. Cases of induction of BP by physical agents (eg, radiation therapy, ultraviolet radiation, thermal or electrical burns, surgical procedures, transplants) are rare, but well-documented events. A contributing role in inducing BP has been suggested for infections, in particular human herpes virus (HHV) infections (cytomegalovirus, Epstein-Barr virus, and HHV-6), but also hepatitis B and C viruses, Helicobacter pylori, and Toxoplasma gondii. Unlike pemphigus, no dietary triggers have been suspected of being involved in the induction of BP. In all patients who have a diagnosis of BP, an environmental agent as a potential cause should always be considered, because the prompt discontinuation of it might result in rapid improvement or even cure of the disease.