While the majority of NL cases are found in patients with diabetes (studies range from 11%-65% of cases), the incidence of NL in diabetic patients is low, only 0.3%-1.2%. NL is also associated with sarcoidosis, inflammatory bowel disease, autoimmune thyroiditis, monoclonal gammopathies, and has even been described in otherwise healthy patients. Importantly, NL may be the first sign of diabetes in a patient with no previous diagnosis. NL typically presents in the third decade of life and later in patients without diabetes. There are documented cases of pediatric onset as well. It is 3 times more common in women than in men and has no known racial predilection.
The exact etiology of NL remains unclear, but microangiopathy due to glycoprotein deposition, immunoglobulin deposition, and abnormal collagen production have all been linked.
NL typically presents unilaterally or bilaterally on the pretibial surface of the lower extremities as well-demarcated yellow, red, or brown atrophic plaques with prominent telangiectasias and an elevated violaceous rim. Atypical cases of NL have been reported on the face, trunk, upper extremities, and penis. The lesions predictably enlarge slowly over the course of months to years without intervention. The lesions may begin as asymptomatic papules, but as they progress, patients often report pruritus, dysesthesia, or pain. NL has the ability to Koebnerize, may ulcerate, and can be exacerbated by trauma. Treatment for NL remains largely unsatisfactory, and the disease process is chronic and, for the most part, progressive.
E13.620 – Other specified diabetes mellitus with diabetic dermatitis
9418005 – Necrobiosis lipoidica
- Majocchi granuloma
- Pretibial myxedema
- Granuloma annulare
- Xanthomas (eg, xanthoma tuberosum, plane xanthoma)
- Diabetic dermopathy
- Chronic stasis dermatitis
- Necrobiotic xanthogranuloma
- Pyoderma gangrenosum
- Panniculitis, including erythema nodosum
- Lichen sclerosus