Background: With the introduction of recombinant formulations insulin allergy is rare, occurring in less than 1% of patients treated with insulin. However, it is a serious situation requiring immediate attention, both due to the hypersensitivity reaction and severe life threatening glucose disequilibrium. Case presentation: A case of a 68-year-old male known diabetic for 35 years noticed some generalized itching, accompanied with maculopapular, mixed vasculitic and bullous lesions. Humalog Mix50/50 was stopped and patient was started on different combinations but to no avail. Before insulin desensitization a trial of degludec was given. Fortunately, the patient tolerated degludec and vildagliptin, and sugars came under control. Conclusion: This combination of multi-hexamer-forming ultra-long-acting insulin plus a DPP4 inhibitor vildagliptin could be an effective combination in controlling blood sugars in patients who have severe allergy to multiple drugs including oral hypoglycemic agents and various insulin preparations.

Keywords: Insulin, allergy, Combination therapy, degludec, vildagliptin, case report