Pictorial CME

Lipoatrophy at Insulin Injection Site

Fig. 1 : Clinical photograph showing extensive lipoatrophy over the anterior abdominal wall.

This 65-year-old lady had diabetes mellitus for the last 7 years and was started on insulin therapy a year and a half ago for secondary sulphonylurea failure and acute inferior wall myocardial infarction. She was on conventional (twice a day) dosing of highly purified bovine insulin (premixed 30% regular + 70% NPH) requiring 34 units/day. Her glycemic control was reasonable with HbA1c of 8.3%.
During her follow up visit, a curious finding of extensive lipoatrophy was noted in the anterior abdominal wall corresponding to the insulin injection site. This complication of insulin therapy is relatively rare and the exact cause is unclear. Previously, when highly purified insulin was not available, the postulates for this complication include immunological reaction to the impurities (including exocrine pancreatic substances) in the insulin preparation. There is no convincing evidence, yet believed that this may be related to animal species of insulin. However, the documentation of lipoatrophy with rDNA human insulin and with Lispro weakens the possibility of its mediation through impurities and species related issues. It is likely to be an immunological phenomenon as postulated that insulin and IgG deposits in subcutaneous tissue of the affected area induce the local overproduction of tumor necrosis factor- α (TNF-α), which inturn inhibits the adipocyte differentiation and consequently resulting into lipoatrophy.
Eventhough our patient did not have much problems in glycemic control, the potential clinical significance of this complication is that it is an important cause of poor glycemic control in a previously euglycemic patient. Changing the brand and species to human insulin and injecting at the site of involvement may sometimes ameliorate the condition cosmetically. This also underscores the importance of checking the insulin injection site before hiking the insulin dose.

P Velayutham, M Shriraam, S Bhadada, A Bhansali

Department of Endocrinology, PGIMER, Chandigarh 160012.
Received : 20.7.2004; Revised : 17.2.2005; Accepted : 23.11.2007