Insulin allergy. Report of a case with delayed local reaction

A diabetic patient had delayed local cutaneous allergic reactions to insulin. We describe his lesion, biopsy findings, and treatment. Allergic reactions to insulin may be immediate local or systemic, which are lgE-mediated. Recommended management of local reactions is to use a single-peak pork insulin of the insulin zinc suspension series. Progressive immediate local reactions may herald the onset of systemic reactions. Hospitalization and desensitization to insulin may be required for systemic allergic reactions to insulin.