Insulin allergy desensitization with simultaneous intravenous insulin and continuous subcutaneous insulin infusion.

Persistent 'IgE-mediated' insulin allergy (type 1 allergy) (1), unresponsive to changes in insulin type or the use of antihistamines, necessitates desensitization. A number of case reports (2-7) and recent reviews (8, 9) have demonstrated that desensitization can be achieved with continuous subcutaneous insulin infusion (CSII), but in type 1 diabetes mellitus, the need to slowly increase insulin dose from sub-therapeutic levels competes with the need for glycaemic control and suppression of ketogenesis. Tolerance to intravenous (IV) insulin despite persistent life-threatening allergic reactions to subcutaneous human insulin (bolus or CSII) has been recently described (10). We present the cases of two unrelated 9-yr-old boys with persistent generalized urticarial reactions to subcutaneous injections of all available insulin types, despite treatment with oral antihistamines. After failed rapid desensitization to insulin delivered by either subcutaneous injection or CSII, the concurrent use of IV insulin allowed desensitization to CSII over 5-6 d.