Rapid Desensitization for Insulin Allergy in Type 1 Diabetes Using an Insulin Pump: A Case Report and Literature Review

OBJECTIVE: Insulin allergy, although uncommon, poses a significant challenge in those with type 1 diabetes mellitus (T1D) as insulin replacement is a necessity. Our objective is to describe a patient in whom rapid desensitization to insulin aspart was achieved using an insulin pump. METHODS: A 40-year-old woman with newly diagnosed T1D developed pruritic wheals over the abdomen after being injected with insulin glargine U-300 (Toujeo) and insulin aspart. Type 1 insulin hypersensitivity was confirmed through intradermal testing and positive insulin-specific immunoglobulin E levels. RESULT: The patient underwent rapid desensitization with an insulin pump. Half the anticipated daily basal requirement was initially subcutaneously administered before initiating low-dose insulin via the pump (0.000025 units/h) and increasing the dose every 30 minutes to reach her basal requirements within 5 hours. Subsequent larger bolus insulin doses did not produce any local or anaphylactic reactions. No pretreatment with corticosteroids or antihistamines was provided. CONCLUSION: Previous protocols for insulin desensitization span over days and often involve routine premedication. The case we presented suggests that insulin desensitization can be achieved over several hours using an insulin pump. A subcutaneous basal insulin cover should be provided prior to desensitization to avoid hyperglycemia necessitating an insulin bolus. Routine premedication may not always be necessary depending on reaction severity.