In their letter to the editor, Damon et al. (1) presented their observation of a local allergic reaction to insulin detemir. According to the patient’s clinical appearance, they classified it as a type III allergy. Another case of a severe injection site reaction to insulin detemir was recently reported by Blumer (2). The described reactions to insulin injection are characteristically similar to a case of type III allergy we managed in our outpatient department in July 2004. We decided to start with insulin detemir to improve glycemic control in the 56-year-old female patient with type 1 diabetes. Diabetes was known for 40 years, and the last 2 years she was treated with intermediate-acting NPH insulin (Insulatard Human; Novo Nordisk) twice daily in combination with insulin aspart (NovoRapid; Novo Nordisk) before each meal. For a short period, the patient received insulin glargine (Lantus; Sanofi-Aventis) in place of NPH insulin. Neither under this therapy nor any other former medication did the patient describe an allergic reaction. Starting with the first injection of detemir, the patient developed local alterations quite similar to that which Darmon et al. reported. We also observed the development of dense, nonerythematous, and painful nodules with a diameter of 0.5 cm that occurred 4–6 h after insulin injection. These reactions persisted on average for 4–5 days and disappeared without intervention. The close temporal and local connection with injection of insulin detemir emphasizes its causal role in this case of allergy. Dermatological testing confirmed the type III reaction, while there was no indication of a type IV allergy. In conclusion, allergy to insulin detemir is rare and previously unreported in the literature, but the observation by Darmon et al. seems to be not the only one.

1.
Darmon P, Castera V, Koeppel MC, Petitjean C, Dutour A: Type III allergy to insulin detemir (Letter).
Diabetes Care
28
:
2980
,
2005
2.
Blumer I: Severe injection site reaction to insulin detemir (Letter).
Diabetes Care
29
:
946
,
2006