An 8 year old boy with a two year history of type 1 diabetes mellitus, treated with purified bovine insulin, developed lipohypertrophy at the site of insulin injection (see fig). Lipohypertrophy is a relatively more common complication than lipoatrophy with purified insulin treatment. It should be specifically looked for before increasing insulin dose whenever a previously euglycaemic patient presents with uncontrolled blood glucose. Good glycaemic control can be achieved by just rotating the injection site in the uninvolved area. The lipohypertrophy is linked to the local lipogenic action of insulin and is more likely related to the frequency of injections at a given site and purity of insulin than to the dose or species of insulin.

When purified insulin preparations were not available, lipoatrophy at the injection site was relatively common, and was attributed to the impurities in the preparation, leading to immune complex deposition and subsequent atrophy.