Necrobiosis Lipoidica in an Adolescent

A 16-year-old girl with type 1 diabetes mellitus had had asymptomatic, sharply demarcated, waxy plaques, with atrophic, shiny centers, in both pretibial areas for several years.

Elias Milgram, MD, of Miami writes that the clinical appearance of these lesions is distinctive for necrobiosis lipoidica (NL), also known as necrobiosis lipoidica diabeticorum. Most cases of NL were originally associated with diabetes mellitus; however, more recent studies seem to indicate that this is not the case.¹ In up to 30% of patients, the lesions precede the onset of diabetes; active diabetes develops in more than half of these patients, and glucose tolerance test results are abnormal in 50% to 87%.^2,3

In NL, collagen degeneration causes a granulomatous response that results in thickened blood vessel walls and fat deposition. Several underlying mechanisms have been suggested, including diabetic microangiopathy, trauma, inflammatory or metabolic changes, and antibody-mediated vasculitis. However, the exact cause remains unknown.

Although NL can affect persons of any age and race and of either sex, it is much more common in women. The average age at onset is 30 years.⁴ NL is rare in young children.⁵

Classic NL usually presents as asymptomatic, shiny or waxy patches on the lower extremities, particularly in the pretibial area. However, NL may occur in other areas, such as the face, scalp, trunk, and upper extremities, where it is more likely to be missed.² The lesions begin as small, well-circumscribed papules or nodules and slowly enlarge over months to years. The initially erythematous patches progressively become more yellow, depressed, and atrophic. Multiple telangiectatic vessels can be seen on the surface of the thinning epidermis.

The effectiveness of different therapies for NL varies. Protection of the legs with elastic support stockings and leg rest may prevent localized trauma, which can cause the lesions to ulcerate. Topical and intralesional corticosteroids can lessen the inflammation of early, active lesions; however, they have little beneficial effect on burned-out atrophic lesions and may cause further atrophy.⁴

Antiplatelet aggregation therapy with aspirin and dipyridamole is believed to prolong platelet survival time and, hence, prevent further worsening of NL. Topical tretinoin may diminish the atrophy associated with NL.⁶