Multifocal fixed drug eruption temporally associated with sitagliptin therapy in type 2 diabetes mellitus

Fixed drug eruption (FDE) is a distinctive cutaneous adverse drug reaction characterised by recurrent, well-demarcated erythematous plaques occurring at the same anatomical site following re-exposure to the offending drug. Although most commonly associated with antimicrobials and non-steroidal anti-inflammatory drugs, dermatological reactions related to dipeptidyl peptidase-4 inhibitors are rarely reported. We describe a man in his 50s with type 2 diabetes mellitus who developed multifocal erythematous plaques over the inframammary region shortly after initiation of sitagliptin therapy. The temporal relationship, characteristic morphology and prompt resolution following drug withdrawal supported the diagnosis of sitagliptin-induced FDE. Lesions resolved within 1 week with residual post-inflammatory hyperpigmentation. This case highlights the importance of recognising uncommon cutaneous adverse drug reactions associated with newer antidiabetic agents and emphasises the role of pharmacovigilance in improving drug safety.