Lipoid necrobiosis (necrobiosis lipoidica) is a relatively rare chronic skin disease. Diabetes account for the majority of cases (approximately 75%), and it can occur in both type 1 and type 2 diabetes. The condition is more common in women (three to five times more than men) and often begins in the 20s or 30s.
The skin disease presents as characteristic, well-defined, reddish-brown patches with central yellowish discolouration and/or ulceration. These patches can be round/oval or irregular and confluent. The edges of the skin lesions often exhibit redness, indicating active inflammation. Approximately one-third of cases develop ulcers.
Lipoid necrobiosis almost always appears on the front of the legs, often bilaterally and fairly symmetrically. In very rare cases, the skin changes may occur in other areas of the body, such as the scalp, face, and arms. The condition is primarily cosmetically bothersome and rarely causes pain or discomfort. However, chronic ulcerative changes can become infected.
The diagnosis is based on the appearance of the skinlesions, often supported by a known diagnosis of diabetes. If there is uncertainty about the diagnosis, a biopsy (tissue sample) may be necessary.
The exact cause is unknown. Altered blood circulationin the skin's smallest blood vessels, a known complication of diabetes, has been speculated to play a role. Microscopic fat deposits may also contribute.
Given the strong association with diabetes, patients with relevant skin changes should undergo diabetes evaluation. Lipoid necrobiosis is also associated with obesity, high blood pressure, elevated cholesterol levels, and thyroid disease.
Current treatment options mainly consist of corticosteroid creams/ointments or corticosteroid injections into and around the edges of the ulcers. Occlusive application of corticosteroids may also be used to enhance treatment effectiveness.
For long-term treatment or in cases of very thin skin (atrophy), non-corticosteroid anti-inflammatory creams/ointments are recommended. Tacrolimus ointments are an alternative. In addition to topical treatments, a select group of patients may be offered PUVA (a form of light therapy).
The skin changes are generally difficult to treat, and complete resolution is often not achieved. The front of the legs is a well-known problematic area with thin and tight skin, where chronic skin changes and ulcers take a long time to heal. To expedite healing and prevent chronic leg ulcers, proper skin care is recommended (avoiding injury, moisturizing the skin, and using compression stockings).
Lipoid necrobiosis has a fairly characteristic appearance. However, it can partially resemble other skin conditions such as granuloma annulare, chronic leg ulcers, and sarcoidosis. In cases of rapidly progressing ulcerative changes, infection and skin cancer should also be ruled out.
