HUMAN INSULIN ALLERGY IMMEDIATE AND LATE-TYPE-III REACTIONS IN A LONG-STANDING IDDM PATIENT

Human insulin allergy-immediate or late type III reaction-is a rare ev ent. We report the case of a 33-year-old female patient with insulin-d ependent diabetes mellitus for 25 years who presented, in the last 8 y ears, mild but generalized urticaria partially controlled with oral an tihistamines. There was no improvement after changing from mixed beef- pork to human insulin. In the last 3 years another allergic manifestat ion began: small, localized, subdermal and painful non-erythematous no dules with central hematomas at injection sites, occurring 6-8 h after the insulin injection and lasting for 48 h. The following maneuvers h ad no benefit: (1) Human insulin (NPH or Lente) administered with dexa metasone or xylocain locally. (2) Short acting human insulin with or w ithout previous boiling. (3) Anti-histamine cetirizine dihydrochloride -10 mg/day. The allergic symptoms disappeared only after treatment wit h short acting human insulin (up to 100 U/day) associated to prednison e-40 mg/day and cetirizine dihydrochloride for 4 months. However, afte r stopping prednisone the urticaria reappeared and it was relieved wit h insulin desensitization. The pain at the site of injections persiste d. Conclusion: This long-standing IDDM patient presented two types of reactions to human insulin: the immediate type (systemic urticaria), t reated with antihistamines and desensitization, and the Arthus' type I II reaction (nodules and hematomas occurring 6-8 h after the insulin i njection) that required glucocorticoid therapy for more than 4 months. (C) 1997 Elsevier Science Ireland Ltd.