Dermatology Online Journal
- Author(s): Wee, Sue Ann, MD
- Possick, Paul, MD
- et al.
From the Ronald O. Perelman Department of Dermatology, New York University
Sue Ann Wee MD, and Paul Possick MD
Dermatology Online Journal 10 (3): 18
A 68-year-old woman presented with a 3-year history of asymptomatic, yellow-brown plaques on the lower extremities with trauma-related superficial ulcers. A biopsy specimen was consistent with necrobiosis lipoidica. Necrobiosis lipoidica is a chronic granulomatous dermatitis that is associated with diabetes mellitus; however, its pathogenesis remains unclear. Topical glucocorticoids are first-line therapy; however, no treatment has proven efficacy in double-blind, placebo-controlled studies.
History.—A 68-year-old woman presented with a 3-year history of papules on the lower extremities. Three years ago, on the anterior aspects of the lower extremities, the patient developed red-brown papules that coalesced into yellow-brown plaques with central atrophy. There has been no regression of any plaques, and the patient experiences intermittent pruritus and occasional superficial ulcers after scratching. Medical history includes rheumatoid arthritis, and a family history includes Type-II diabetes mellitus.
Physical examination.—Approximately 25 well-demarcated, yellow-brown atrophic plaques with induration and overlying superficial telangiectases were present on the anterior tibial surfaces of the lower extremities. There were erosions on two of the plaques.
|Figure 1||Figure 2|
Laboratory data.—A complete blood count with differential analysis, basic metabolic panel, hepatic function tests, blood glucose level, and urinalysis were normal.
Histopathology.—Throughout a fibrotic dermis and thickened subcutaneous septa, there is a diffuse and multinodular infiltrate of Langhans and foreign-body-type giant cells, histiocytes, lymphocytes, and plasma cells. In many foci there is a palisaded arrangement of the granulomatous infiltrate around areas of degenerated collagen. A periodic-acid-Schiff stain for fungi and a Fite stain for acid-fast bacilli are negative. Refractile foreign bodies are not apparent with polarized light.
Necrobiosis lipoidica (NL) is a chronic granulomatous dermatitis that is associated with Type-I diabetes mellitus and less frequently with Type-II diabetes mellitus. NL appears on the pretibial regions as yellow-brown, telangiectatic plaques with central atrophy and raised, violaceous borders. Ulcers, which are often induced by trauma, occur in 35 percent of lesions. Less common locations include the upper extremities, face, and scalp, where plaques tend to have annular or serpiginous morphologies. Except when they are ulcerated, the lesions are generally asymptomatic. Occasionally, pruritus, anesthesia, pain, hypohidrosis, and alopecia at affected sites have been reported. Severe, ulcerative NL may also occur, and it is often refractory to therapy.  Squamous cell carcinomas have rarely been reported to arise in areas of necrobiosis lipoidica. 
The average age of onset is 30-40 years, but it may occur at any age. The female-to-male ratio is approximately 3:1. Despite the high prevalence of diabetes mellitus in patients with NL,  the reported prevalence of NL in diabetic patients is only 3 per 1000. There is no relation between a patient's glycemic control and the likelihood of developing NL lesions, but diabetic patients with NL appear to have higher rates of diabetes-related end-organ damage.  Spontaneous remission with residual scars and atrophy was observed in 17 percent of 171 patients.  NL has also been reported in association with Crohn's disease, ulcerative colitis, granuloma annulare, and sarcoid.
The cause of NL remains unknown. The findings of immunoreactants IgM, IgG, IgA, and C3 deposited in blood vessel walls of both lesional and uninvolved skin of individuals with NL and of vasculitis support the role of immunologically mediated vascular disease as the primary cause of altered collagen in NL.  Microangiopathic vascular changes seen in individuals with diabetes mellitus and increased platelet aggregation have also been implicated. Some investigators consider NL to be a primary disease of collagen, with inflammation occurring as a secondary event. 
There is no treatment for NL that has proven efficacy in double-blind, placebo-controlled studies. First-line therapy includes potent topical glucocorticoids for early lesions and the injection of glucocorticoids into the active borders of established lesions. Systemic glucocorticoids are also effective, but they may elevate serum glucose. Other therapies attempt to decrease the microangiopathy and vascular thrombosis by increasing fibrinolysis or decreasing platelet aggregation and thromboxane A2 synthesis.  Anecdotal reports or uncontrolled case series mention stanozolol, inositol niacinate, nicofuranose, ticlopidine hydrochloride, pentoxifylline, and chloroquine.  Aspirin plus dipyridamole versus placebo showed no appreciable effects on treatment.  Systemic cyclosporine was successfully used to treat four patients with ulcerating NL on the lower legs.  Other reported therapies include topical PUVA photochemotherapy, topically applied GM-CSF, bovine collagen, topical tretinoin, and mycophenolate mofetil. In light of its tendency to occur on sites of anterior tibial trauma, one should also educate patients about avoidance of leg injury. 
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