Successful management of type IV hypersensitivity reactions to human insulin analogue with injecting mixtures of biphasic insulin aspart and dexamethasone.

Although hypersensitivity reaction to insulin was supposed to be less-frequent with current insulin analogue, case reports with different types of allergic reactions to insulin analogue were still reported. The most common form is type I hypersensitivity reaction with IgE-mediated. Besides, type III (IgG and IgM-mediated) and type IV (T-cell mediated delayed reaction) hypersensitivity reactions were also reported. Here we presented a long-standing type 2 diabetes with insulin requirements with hypersensitivity reactions to insulin actrapid, insulin aspart, insulin glargine, insulin detemir, and biphasic insulin aspart 30. Insulin desensitization was performed as initial management but failed as skin biopsy with immunohistochemical staining proved type IV hypersensitivity reaction. We continued with the next treatment approach using subcutaneous injection with the mixture of biphasic insulin aspart 30 and dexamethasone to alleviate allergy, and the result was successful with steroid-free biphasic insulin aspart 30 injection eight months later. Besides, the treatment effect had lasted after ten years even with switched type of insulin analogue from biphasic insulin aspart 30 to insulin glargine and insulin aspart. The case report demonstrated a good example of how clinicians deal with the rare but important questions of hypersensitivity reactions to insulin analogue.