Endocrine Abstracts

JOINT3501

Introduction: Insulin allergy is a rare complication whose clinical manifestations can range from localized skin reactions to more generalized reactions. We report a case of localized urticarial reaction in a diabetic patient treated with human insulin.

Case Report: This is a 23-year-old patient, diagnosed with diabetes one year ago, initially placed on human intermediate-acting insulin (twice daily) and rapid-acting insulin (preprandial), and currently on human mixed insulin (two injections daily). The patient was admitted to the endocrinology department of CHU Mohamed VI for further management of his diabetes. Upon examination, the patient presented with pruritic urticarial lesions localized to the site of injection of the mixed human insulin. The biological tests did not reveal eosinophilia. In our institution, the patient received an injection of long-acting insulin analogue (glargine) and rapid-acting insulin analogues before meals. The clinical course was marked by the resolution of the urticarial reaction at the insulin injection site.

Discussion: Insulin allergy is not always directly related to the insulin molecule itself. It may result from a reaction to one of the excipient components, such as hydrochloric acid, water for injection, glycerol, meta-cresol, phenol, disodium phosphate dihydrate, protamine sulfate, sodium hydroxide, or zinc chloride. It can also be caused by an element used in the injection, such as the nickel in the needle. Thus, insulin can act as an allergen, inducing a pathological reaction, although the exact mechanisms of this response are not fully understood. The use of a different type of insulin allowed for better clinical tolerance.

Conclusion: Allergic reactions to insulin, although rare, remain an important complication, especially in type 1 diabetics. These reactions can disrupt glycemic control, making disease management more challenging. It is therefore crucial to diagnose these allergies promptly and provide appropriate management to ensure the safety and efficacy of the treatment.