Research
Hypersensitivity to Insulin Degludec: Case Analysis and Management Perspectives
From the introduction of human recombinant insulin preparations, insulin allergy has become rare, with a reported prevalence of approximately 2.4% (1). Most insulin injection reactions are immediate and IgE-mediated and can be classified as either Type I or Type IV hypersensitivity (1). In this case report we elaborate on a case of a 32-year-old female with latent autoimmune diabetes in adults (LADA) who presented with episodes of itching and rash 20-30 minutes after injecting premixed analog insulin (Aspart and Degludec) at night for one week. During this time, her symptoms resolved with oral antihistamines and steroids. Notably, she had no prior history of allergies. A skin prick test was done separately with Aspart and Degludec, given the suspicion of an insulin injection reaction. The test yielded an immediate positive result for Degludec. Additives such as zinc or metacresol present in Degludec are potential culprits behind the hypersensitivity reaction. Diagnostic tests such as skin prick tests, intradermal skin tests, and serum IgE levels can confirm the diagnosis of insulin injection reactions (1). This case report highlights the importance of effectively diagnosing and managing insulin injection reactions.
Insulin Autoimmune Syndrome Treated with Plasmapharesis
A 66-year male with a history of Central Serous Retinopathy presented with recurrent episodes of hypoglycemia. On evaluation, he was found to have insulin-mediated hypoglycemia with serum insulin of 300uIU/ml, C peptide 27.51ng/ml, when the blood glucose was 46mg/dl. High insulin levels above 100uIU/ml, led to suspicion of Autoimmune hypoglycemia and were confirmed by a high anti-insulin antibody titer of 300U/ml. Imaging was negative for Insulinoma. The patient was started on low dose oral prednisolone under ophthalmological monitoring, but as there was no symptomatic improvement, the dose was increased following which there was a flare-up of CSR. The patient was initiated on plasmapheresis following which his hypoglycemia improved with drop in anti-insulin antibody titers to 29U/ml. The patient was maintained on low dose steroids, which were tapered and stopped over the next six months with complete resolution of hypoglycemia and normalization of anti-insulin antibody titers.
