Necrobiosis Lipoidica 

Necrobiosis lipoidica is a disorder of collagen degeneration with a granulomatous response, thickening of blood vessel walls, and fat deposition. The main complication of the disease is ulceration, usually occurring after trauma. Infections can occur but are uncommon. There have been rare reported cases of squamous cell carcinomas developing in chronic lesions of necrobiosis lipoidica. (See Etiology, Prognosis, Presentation, and Workup.)^{[1, 2]}

The condition was first described in 1929, by Oppehhein, who called it dermatitis atrophicans lipoidica diabetica; in 1932, however, the disease was renamed necrobiosis lipoidica diabeticorum (NLD), by Urbach.

In 1935, Goldsmith reported the first case in a nondiabetic patient. Other cases of necrobiosis lipoidica diabeticorum in nondiabetic patients were described by Meischer and Leder, in 1948. Rollins and Winkelmann, in 1960, also described this condition in nondiabetic patients, and a renaming of the disorder was suggested to exclude diabetes from the title.^[3] Today, the term necrobiosis lipoidica is used to encompass all patients with the same clinical lesions, regardless of whether or not diabetes is present. (See Presentation and Workup.)

Despite extensive studies, the etiology of necrobiosis lipoidica is still uncertain. Because of the strong relationship between diabetes and necrobiosis lipoidica diabeticorum, many studies have focused on diabetic microangiopathy as the leading etiologic theory. Diabetic alterations of the kidney and eye vasculature are similar to the vascular changes seen in necrobiosis lipoidica. A deposition of glycoprotein in blood vessel walls may be the cause of diabetic microangiopathy. A similar glycoprotein deposition is seen in necrobiosis lipoidica.

Another theory is based on the deposition of immunoglobulins, the third component of complement and fibrinogen in the blood vessel walls of patients with necrobiosis lipoidica. Some believe that an antibody-mediated vasculitis may initiate the blood vessel changes and subsequent necrobiosis in necrobiosis lipoidica.

An additional etiologic theory focuses on the abnormal collagen in necrobiosis lipoidica. It is well established that abnormal and defective collagen fibrils have been responsible for diabetic end-organ damage and accelerated aging. Lysyl oxidase levels have been found in some diabetic persons to be elevated and are responsible for increased collagen cross-linking. Increased collagen cross-linking could explain basement membrane thickening in necrobiosis lipoidica.

Other theories link trauma and inflammatory and metabolic changes as a possible etiology. It also has been found that there may be impaired neutrophil migration leading to an increased number of macrophages, possibly explaining the granuloma formation in necrobiosis lipoidica. The pathogenesis of necrobiosis lipoidica has not been demonstrated to be linked to genetic factors.

Tumor necrosis factor (TNF)–alpha has a potentially critical role in conditions such as disseminated granuloma annulare and necrobiosis lipoidica. It is found in high concentrations in the sera and skin in patients with these conditions.

The average age of onset for necrobiosis lipoidica is 30 years, but it can occur at any age. The age of onset ranges from infancy to the eighth decade. The disease tends to develop at an earlier age in patients with diabetes. It also shows a sex predilection, being 3 times more common in women than in men.

Occurrence in the United States

Necrobiosis lipoidica has been described in about 0.3% of diabetic patients. In one study, necrobiosis lipoidica was shown to precede the onset of diabetes mellitus in 15% of patients. In addition, 60% of patients had the diagnosis of diabetes mellitus prior to the onset of necrobiosis lipoidica, while 25% of patients had lesions that appeared with the onset of diabetes mellitus. The presence or progression of necrobiosis lipoidica does not correlate with how well diabetes is controlled.

Treatment for necrobiosis lipoidica is not very satisfactory. The disease is typically chronic with variable progression and scarring. Squamous cell cancers have been reported in older lesions of necrobiosis lipoidica related to previous trauma and ulceration.^[1]

From a cosmetic standpoint, the prognosis of necrobiosis lipoidica is poor. Treatment is helpful in halting the expansion of individual lesions, which tend to run a chronic course. Lesional ulcerations can cause significant morbidity, requiring prolonged wound care. These ulcerations can be painful, become infected, and heal with scarring.