Endocrine Abstracts

Aim: Recent reports of adverse skin reactions in patients receiving dipeptidyl peptidase-4 (DPP-4) inhibitors have increased awareness towards skin-targeting side effects. Bullous pemphigoid (BP) is an autoimmune blistering dermatosis with significant morbidity and mortality. We report the development of BP in patients with type 2 diabetes mellitus (T2DM) treated with DPP-4 inhibitors.

Method: Evaluation of the temporal distribution of the frequency of BP diagnoses with respect to T2DM comorbidity and the use of DPP-4 inhibitors during a 7-year-period (01/2007–12/2013) in a single center. The diagnosis of BP was based on clinicopathological correlation and direct and indirect immunofluorescent staining.

Results: Seventy consecutive patients with newly diagnosed BP were included in the study (age range: 64–95). At the time of BP diagnosis, 29 patients (41%) were co-morbid for T2DM, 20 of them (69%) under treatment with DPP4-inhibitors for 2–18 months (median 8) prior to BP diagnosis. Moreover, the number of patients with diagnosis of BP co-morbid for T2DM was unequally distributed in time, in correlation to the increasing use of DPP-4 inhibitors for T2DM following their introduction in 2007 in Greece (P=0.03, Fisher’s exact test, comparison of frequency of T2DM in BP cases between 2007–2009 and 2010–2013 time periods). In particular, between 2007 and 2009 (when DPP4 inhibitor use in Greece was <6.3%) none of the BP patients with T2DM were on treatment with DPP-4 inhibitors (4/22, 18%). However, between 2010 and 2013 (when DPP4 inhibitor use had increased to 9.4–15.7%), 29/48 (60%) patients with BP had T2DM and the majority of them (20/29=69%) were on DPP-4 inhibitors.

Conclusion: We report an increasing frequency of BP in T2DM patients on treatment with DPP-4 inhibitors, compatible with a group-specific adverse drug reaction. BP should be suspected in T2DM patients on DPP-4 inhibitors, especially elderly ones, who complain for the development of any itching dermatosis.