Necrobiosis lipoidica (Video)

Rashes on the front of the shin are seen commonly with lichen simplex chronicus which is very itchy  and also with this condition, necrobiosis lipoidica diabeticorum (NLD). It is a condition you see in diabetics or pre diabetics. It is non scaling, not itchy and just slowly expands. The cause is not known but it is thought to be related to diabetes induced vascular damage. Although only about 22% of patients with NLD have diabetes those diabetics who also have NLD have an increased incidence of neuropathy, retinopathy and joint immobility. These lesions have recurred around a large plaque that had been treated with intralesional steroid injections into the inflamed edge. Most lesions have a raised edge and a central atrophic area where the underlying veins can be easily seen. Sometimes the underlying fat gives them a yellowish tinge. A punch biopsy of the edge should always be sutured as injuries here are very slow to heal. No other treatment has been shown to work in double blind trials.

Necrobiosis Lipoidica

Lesions on the anterior shin can be a skin cancer or psoriasis but if red non scaly with a raised edge then the likeliest diagnosis is necrobiosis lipoidica. This condition is most often seen in diabetics or pre diabetics where it starts as a small flat pink macule that gradually increases in size and develops a papular edge. The central epidermis may thin, allowing the underlying yellow of the fat to appear centrally with prominent veins. If this area is traumatised it ulcerates easily and is very slow to heal. For early lesions the best way to stop progression is to inject  Kenacort A10 diluted with 3 mls of local anaesthetic to 2.5 mgs per ml  into the lesion edge. This can be repeated after 4 weeks. Other measures are used to increase peripheral blood flow such as   Pentoxifylline or low dose aspirin and dipyridamole. Around 75% of patients who have necrobiosis lipoidica will ultimately develop diabetes mellitus.