Introduction: Insulin allergy is a rare clinical condition. The frequency of insulin allergy has decreased since highly purified insulin préparations became available. However, it remains a concern, and its frequency may have increased with the latest generation of insulin analogues. Case Presentation: We report the case of a 51-year-old female patient with type 2 diabetes who required multiple daily insulin injections. The patient developed an allergy to human regular insulin and insulin analogues (insulin aspart and insulin glargine), which was resolved through subcutaneous insulin desensitization. Conclusion: As reported in this case, desensitization with subcutaneously administered human insulin using an ultra-rush protocol in patients with insulin allergy may offer a simple and successful therapy within a few days.