Relapse of bullous pemphigoid: an update on this stubborn clinical problem.

Bullous pemphigoid (BP) is a chronic autoimmune blistering disorder that has a predilection for the elderly. It is characterized by a poor prognosis due to its high mortality rate and the tendency to relapse. The relapse rate of BP ranges from 27.87% to 53% after disease remission, while the majority of relapses occur early (within 6 months) during remission. Clinical interventions aimed to prevent early relapses could reduce potential complications from first-line treatment and make follow-up care easier for clinicians in practice, thus improving the prognosis of BP and the quality of patients' lives. In this article, we attempt to review previous studies from the medical literature concerning relapse and risk factors related to relapse in BP patients. Treatments found to be able to reduce or increase relapse rate were also discussed. We propose that clinicians be aware of these risk factors and manage proper treatment accordingly. Key Messages   • The relapse rate of bullous pemphigoid ranges from 27.87% to 53% after disease remission, while the majority of relapses occur early (within 6 months) during remission.   • Ageing, disease severity, neurological disorder, serum ECP, BAFF, IL-17, IL-23, CXCL10 and anti-BP180 antibody levels have been shown to be related to relapse, while confirmation studies are needed before using them for guidance for relapse prevention.   • Longer usage of corticosteroid with a low dose, combination of immunosuppressants and intravenous immunoglobulin are helpful in lowering relapse rate.