Publication

Abstract : Background: Dipeptidyl peptidase (DPP)-4 plays a complex role in immune regulation and its inhibition can have effects on the pathogenesis of various skin diseases. Studies have shown that DPP-4 inhibitors are associated with an increased risk of bullous pemphigoid (BP). Aim: To analyse the clinical and histopathological features of cutaneous adverse events in patients on DPP-4 inhibitors. Methods: We performed a retrospective review of patients with suspected DPP-4 inhibitor-associated cutaneous adverse events, at a tertiary teaching hospital from 1 January 2017 to 31 December 2020. Exclusion criteria included previous history of chronic skin disease and lack of histopathological reports or follow-up records. The clinical characteristics, latency period, Naranjo Adverse Drug Reaction Probability Scale and clinical outcomes were evaluated. Results: In total, 18 patients (10 men, 8 women; mean age 68.6 years, range 38-89 years) were included. The DPP-4 inhibitors used were teneligliptin (n = 6), vildagliptin (n = 6), sitagliptin (n = 4), linagliptin (n = 1) and saxagliptin (n = 1). The mean interval between therapy initiation and lesion onset was 8.8 months (range 1-24 months). The dermatoses noted were BP (n = 12; 66.6%), lichenoid dermatitis (n = 4; 22.2%), psoriasiform dermatitis (n = 1; 5.6%) and spongiotic dermatitis (n = 1; 5.6%). Eight patients (44.4%) had necrotic keratinocytes as one of the distinct histological features. Causality assessment using the Naranjo scale rated the causative role of DPP-4 inhibitors as 'possible' in all patients. Of the 18 patients, 11 (61.1%) noted improvement in their condition following discontinuation of DPP-4 inhibitors, with 5 having complete remission within 6 months of stopping the drug.