Endocrine Abstracts

Insulin allergy has become uncommon (<1%) with the wider use of human and analogue insulin in recent decades. We report a case of multiple analogue insulin allergy. A 71 year old woman with an eleven year history of Type 2 diabetes was referred to our Diabetes service. She had a BMI of 37.5 kg/m². She was in tolerate of metformin. HbA1c was 12.4% on gliclazide and sitagliptine. She was commenced on Novomix 30. Within four days of therapy, she developed generalised pruritis, swelling of face and neck with erythematous lesions around the injection site which resolved after stopping insulin. Subsequently start on Humalog Mix 25 led to burning sensation over her face and neck, peeling of skin and a sore throat. She reported allergy to fish. Insulin was discontinued and referred to immunology work up after recommencing gliclazide along with a GLP1 analogue. Specific IgE antibodies to insulin and protamine were negative. Skin prick test for Humalog Mix 25, Novomix 30, protamine and actrapid all tested negative. She was tested positive for protamine following intra-dermal test. Intermediate acting human insulin (NPH) and biphasic insulin (human and analogue mixes) contain protamine. Short acting insulin (regular and analogue) with basal analogue insulin are protamine free.

Conclusion: Cardiovascular disease is two to three fold higher in diabetic individuals and so is the need for cardiac catheterization or CABG. Intravenous Protamine is widely used post-catheterization and following CABG to reverse the effects of heparin. Major adverse reactions to intravenous protamine are well documented and are fifty times higher in patients previously sensitised to protamine insulin1 with reports of death2 in some patients and hence need a prompt workup to exclude protamine allergy. 1. Increased risk of severe protamine reactions in NPH insulin-dependent diabetics undergoing cardiac catheterization. WJ Stewart, SM McSweeney, MA Kellett, DP Faxon and TJ Ryan. 2. Allergic shock and death associated with protamine administration in a diabetic patient Chu YQ, Cai LJ, Jiang DC, Jia D, Yan SY, Wang YQ.

Declaration of interest: There is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported.

Funding: No specific grant from any funding agency in the public, commercial or not-for-profit sector.