Bullous pemphigoid arising in a patient with acquired perforating dermatosis

Risk of bullous pemphigoid and pemphigus in patients on chronic dialysis: A nationwide population-based cohort study

Bullous pemphigoid has a high incidence among dialysis patients. However, whether or not chronic dialysis is an independent risk factor of bullous pemphigoid remains unclear. We aimed to investigate the effect of chronic dialysis on the development of bullous pemphigoid and pemphigus. We performed a retrospective cohort study using records from Taiwan's National Health Insurance Research Database between 2008 and 2019. We identified a dialysis cohort that included patients on chronic hemodialysis and peritoneal dialysis, and the hazard ratios (HRs) for bullous pemphigoid and pemphigus were compared with those of a sex-, age-, and index-matched cohort, then the results were adjusted for various confounding factors. Among 93 538 patients on chronic dialysis and 93 538 patients in the control group, 287 and 139 developed incident bullous pemphigoid, and 45 and 35 developed incident pemphigus after a median follow-up of 3.7 and 5.6 years, respectively. The incidence rates of bullous pemphigoid in the dialysis patients and the control group were 74.2 and 25.2 per 100 000 person-years, respectively (difference between groups, P < 0.0001). The incidence rates of pemphigus in the dialysis patients and the control group were 11.6 and 6.3 per 100 000 person-years, respectively (difference between groups, P < 0.01). Cox proportional hazard adjustment showed the HR for bullous pemphigoid in dialysis patients was 2.12 (95% confidence interval [CI] 1.64-2.74, P < 0.0001) compared with the control group. Dialysis patients aged <75 years had an even higher risk of bullous pemphigoid development (5- to 8-fold) than the control group. The adjusted HR for pemphigus was not elevated in dialysis patients (adjusted HR 1.52, 95% CI 0.87-2.67, P = 0.14). Chronic dialysis is an independent risk factor for developing bullous pemphigoid, but not a risk factor for pemphigus. Physicians should be aware of the predisposition of chronic dialysis patients to bullous pemphigoid.

Dipeptidyl peptidase-4 inhibitor-associated bullous pemphigoid in a patient with acquired reactive perforating collagenosis

Bullous pemphigoid (BP) is a common autoimmune blistering disorder with unknown etiology. Recently, increasing numbers of BP cases which developed under the medication with dipeptidyl peptidase-4 inhibitors (DPP4i), widely used antihyperglycemic drugs, have been reported in published works. Here, we report a case of DPP4i (teneligliptin)-associated BP that developed in a 70-year-old Japanese man. Interestingly, the patient had acquired reactive perforating collagenosis (ARPC), which is also known to be associated with the onset of BP. In the present case, clinical, histopathological and immunological findings suggested that DPP4i rather than ARPC was associated with the onset of BP.