Atypical clinical manifestation and protracted latency are observed in the emerging variant of checkpoint inhibitor-associated bullous pemphigoid

The last two decades have witnessed a substantial increase in the incidence of bullous pemphigoid (BP) worldwide.¹ One of the most compelling interpretations accounting for this epidemiological observation is the growing exposure to novel drug classes that might be implicated in eliciting the disease.¹ Multiple lines of evidence have recently accumulated to suggest that exposure to dipeptidyl peptidase 4 (DPP4) inhibitors and checkpoint inhibitors (CPIs) is associated with an elevated risk of BP.^2,3 As these drugs were introduced only in the past two decades, their rising utilization underlies, at least in part, the growing incidence of BP.¹