Update on necrobiosis lipoidica: a review of etiology, diagnosis, and treatment options.

Necrobiosis lipoidica (NL) is a rare chronic granulomatous disease that has historically been associated with diabetes mellitus. Debate exists regarding the etiology and pathogenesis of NL with a widely accepted theory that microangiopathy plays a significant role. NL typically presents clinically as erythematous papules on the front of the lower extremities that can coalesce to form atrophic telangiectatic plaques. NL is usually a clinical diagnosis, but if the clinical suspicion is uncertain, skin biopsy specimen can help differentiate it from sarcoidosis, necrobiotic xanthogranuloma, and granuloma annulare. NL is a difficult disease to manage despite a large armamentarium of treatment options that include topical and intralesional corticosteroids, immunomodulators, biologics, platelet inhibitors, phototherapy, and surgery. Randomized control trials are lacking to evaluate the many treatment methods and establish a standard regimen of care. Disease complications such as ulceration are common, and lesions should also be monitored for transition to squamous cell carcinoma, a less common sequelae.