Formerly known as necrobiosis lipoidica diabeticorum, necrobiosis lipoidica is far more common in patients with diabetes than in the general population. However, it is still a relatively rare disorder, with less than 1% of diabetes patients affected.
Necrobiosis lipoidica is a chronic, usually painless, inflammation of the skin consisting of raised reddish-brown lesions typically located in the pre-tibial area. Sometimes, particularly following local trauma, painful central ulceration may occur.
Figure 1. Necrobiosis Lipoidica in a type 1 diabetes patient. (note the depressed atrophic center of the medial laesion)The lesions enlarge and merge into larger plaques which eventually become areas of shiny yellowish atrophic plaques with depressed centres (figure 1). Women are twice as frequently affected as men.
The pathogenesis of necrobiosis lipoidica is not clear. Histologically, the affected skin is characterized by degeneration of the collagen in the skin and a granolumatous inflammation of the subcutaneous fat which results in necrosis followed by atrophy. The fact that those with necrobiosis lipoidica appear to be at increased for nephropathy and retinopathy suggests that microangiopathy may also play a role in the pathogenesis. Trauma may be a precipitating factor, as laesions seem to develop on sites of minor injury.
While necrobiosis lipoidica is usually painless, the laesions are highly disfiguring and patients will usually look for some form of treatment. Even though there is no clear relation with glycaemic control, the possible role of micro-angiopathy in the pathogenesis has led to the recommendation to try and improve glycaemic control and to stop smoking. Many other therapies have been tried but unfortunately none have clearly been shown to be effective and many have considerable side-effects, so caution is advised in applying them. Therapies reported in the literature include:
- Topical or intralesional corticosteroids
- Systemic corticosteroids
- Aspirin and dipyridamole
- Laser surgery
- Excision and dermal grafting
- Topical psoralen with ultraviolet A
- Topical calcineurin inhibitors
- Hyperbaric therapy
- Anti-TNF-α therapy
^ Suárez-Amor O, Pérez-Bustillo A, Ruiz-González I, Rodríguez-Prieto MA. Necrobiosis lipoidica therapy with biologicals: an ulcerated case responding to etanercept and a review of the literature. Dermatology 2010;221(2):117-21.