IgE antibody studies in a case of generalized allergic reaction to human insulin

Allergic reactions to human insulin: a review of current knowledge and treatment options

Although the incidence of insulin allergy decreased after the introduction of recombinant human insulin preparations, it is still a major problem which may be life-threatening in some cases. In this article, we attempted to review current knowledge concerning allergic reactions to human insulin and discuss the available treatment options of insulin allergy.

Insulin allergy: clinical manifestations and management strategies

Insulin allergy in patients with diabetes mellitus on insulin treatment is a rare condition. It is suspected upon noticing immediate symptoms following insulin injections. The immediate vital implications for the patient call for prompt diagnosis and management of insulin allergy. We review current knowledge and procedures based on four diabetic patients who presented in our clinic. Insulin allergy was suspected as they showed immediate symptoms after insulin injection (urticaria, rash, angioedema, hypotension, dyspnea). A detailed allergologic work-up was performed and adequate therapy was initiated. In three of the four patients, a specific immunotherapy was started whereas in one patient a switch to oral antidiabetics was possible and consequently initiated. By standard prick testing and measurement of specific IgE antibodies, a type 1 IgE-mediated allergy was confirmed. After initiation of insulin immunotherapy, the symptoms completely resolved in two out three of patients and significantly improved in the third patient. The fourth patient was successfully switched to oral antidiabetics. Insulin allergy is a rare but severe condition that calls for immediate allergological work-up. It can be managed well in close cooperation between the diabetologist and the allergologist. Specific immunotherapy is efficient and should be considered.

Primary systemic allergy to human insulin: recurrence of generalized urticaria after successful desensitization

Primary systemic allergy to human insulin is rare. We report a case of recurrent immediate local reactions followed eventually by generalized urticaria to recombinant human insulin (Humulin) in an insulin-dependent diabetic. Skin test to Humulin R was positive, and the patient was successfully desensitized using a modified rapid desensitization protocol. Two weeks later, he had another episode of generalized urticaria after Humulin R injection. His treatment was resumed at a lower dose, and within a week he was able to tolerate his usual regimen of insulin. To our knowledge, this is the first report of a recurrence of systemic reaction after successful desensitization.

Resistance and allergy to recombinant human insulin

Insulin allergy and antibody-mediated resistance may complicate therapy with animal insulins. We describe a 53-year-old man manifesting both resistance and persistent systemic allergy despite treatment with recombinant human insulin. Insulin resistance and symptoms of allergy appeared in this patient several months after initiating therapy with mixed beef-pork insulin, as is often the case. Symptoms initially improved, but persisted, and then worsened again, despite continuous human insulin therapy. Total insulin-binding capacity by Scatchard analysis, high plasma insulin-binding capacity, and specific anti-insulin antibody levels were consistent with an immunologic form of insulin resistance. Glucocorticoid therapy was required both to reduce allergic findings and to restore glycemic control. Although recently available human insulins may be less immunogenic than animal forms, immune responses to exogenous human insulin still may pose significant clinical problems.