Insulin Injection-Site Acanthosis Nigricans: Skin Reactions and Clinical Implications
Background: Insulin injection-site acanthosis nigricans and other local cutaneous reactions may occur from repeated same-site insulin injections. The purpose of this article is to describe a case of acanthosis nigricans resulting as a localized reaction to insulin injections, review medical literature describing injection-site acanthosis nigricans resulting from same-site insulin injections, describe other injection-site cutaneous reactions related to insulin administration, and discuss clinical implications and lessons learned from the literature.
Case Presentation: A 75-year-old patient with a history of type 2 diabetes mellitus presented with 2 discrete hyperpigmented plaques on the anterior abdominal wall, suggestive of acanthosis nigricans and confirmed on histopathology. These lesions were localized to the site of insulin injection and improved after the patient started rotating insulin injection sites.
Conclusions: Rotation of insulin injection sites is an effective way to prevent and reduce cutaneous complications of insulin therapy. In addition to improving education regarding insulin injection technique, diabetes health care professionals should inspect injection sites at each patient encounter. Most cutaneous complications are asymptomatic but may impact glycated hemoglobin (HbA 1c ), cosmetic appearance, insulin absorption, and required dose of insulin.
Conclusions
Cutaneous complications are a local adverse effect of long-term failure to rotate insulin injection sites. Our case serves as a call to action for HCPs to improve education regarding insulin injection-site rotation, conduct routine injection-site inspection, and actively document cases as they occur to increase public awareness of these important complications.
If a patient with DM presents with unexplained poor glycemic control, consider questioning the patient about injection-site location and how often they are rotating the insulin injection site. Inspect the site for cutaneous complications. Of note, if a patient has a cutaneous complication due to insulin injection, adjust or decrease the insulin dosage when rotating sites to mitigate the risk of hypoglycemic episodes.
Improvement of glycemic control, cosmetic appearance of injection site, and insulin use all begin with skin inspection, injection technique education, and periodic review by a HCP.
