Defining dipeptidyl peptidase‐4 inhibitors‐related bullous pemphigoid: A single‐centre retrospective study

Background Many studies have corroborated the association of dipeptidyl peptidase‐4 inhibitors (DPP4i) use with bullous pemphigoid (BP). It has been speculated that this drug‐induced variant presents with a different clinical spectrum than conventional BP. Objective To determine the prevalence of DPP4i‐induced cases of BP and to evaluate whether gliptin‐related BP has specific clinicopathological and immunological features. Methods We conducted a retrospective, observational study of BP cases attended at our centre between January 2000 and June 2020. Epidemiological, clinical, histopathological and laboratory data were collected. Results A total of 257 cases of BP were collected; 51 (24.3%) were on treatment with DPP4i. When analysing DPP4i‐induced BP cases, generalized BP was the predominant pattern and scalp/mucosal involvement was found in 13 patients. Gliptin‐related BP cases were associated to a decrease in the eosinophilic infiltrate (p = 0.000) and both the detection rate and concentration of anti‐BP180 IgG were lower (p = 0.004, p = 0.001, respectively) than non‐DPP4i cases. Limitations Retrospective, single‐centre study. Conclusion Our large DPP4i‐induced BP case series has highlighted that DPP4i‐induced BP is characterized by generalized lesions and scalp involvement. Lower titres of anti‐BP180 antibodies and a decrease in eosinophils infiltrating into the skin may be distinct features of DPP4i‐related BP.