Answer:
Necrobiosis lipoidica diabeticorum: Characterized by irregular, ovoid plaques with a violaceous, indurated periphery and a yellow central atropic area, this entity is strongly associated with diabetes mellitus. Because of its unknown cause and the fact that many cases occur in nondiabetics, many choose to call it by the shorter necrobiosis lipoidica (or NL). Lesions can start as small, firm , red-brown papules that slowly enlarge and develop the typical violet-brown periphery and yellow-brown center. They often occur on the pretibial area and are usually multiple and bilateral. Ulceration often occurs as a result of minor trauma, however, the ulcers rarely become infected even in diabetics. The prevalence of NL in diabetics is about 3 per 1000 with females outnumbering males 3 to 1. It occurs in patients of any age though it seems to occur at a slightly earlier age in diabetics (average age 30 vs. 41 for nondiabetics). Smoking does not seem to be a risk factor. Almost a fifth of patients will show spontaneous resolution though this may be over a period of up to 30 years. A consistently effective treatment for NL has yet to be found. Control of NL is not related to serum glucose control. Medical treatments have included corticosteroids both topical and intralesional, fibrinolytic agents, and antiplatelet and antithrombotic agents. Ulcerative NL cases usually respond to local wound care but occasionally they require surgical excision. This is usually accomplished by excision to deep fascia or periosteum with split-thickness skin grafting or skin flaps. Patients with NL should be educated to avoid to anterior leg trauma.