Necrobiosis Lipoidica

Basics

Necrobiosis lipoidica (NL) is a granulomatous skin disease.
Presents with red-brown papules that develop into plaques with violaceous or red-brown raised borders and atrophic, yellow-brown, telangiectatic centers
Most commonly occurs on the pretibial area
Ulceration is the most common complication.
Historically associated with diabetes mellitus (DM), although this association is now questioned
Management is difficult but includes medical and/or surgical treatment.

0.3–1.2% of DM patients have NL (1).
15–65% of NL patients are reported to have DM (1).
Female > male (3:1) (1)
Average age of onset is the 3rd or 4th decade of life; may also occur in children (rare) and the elderly

Exact etiology remains unknown.
One theory suggests that NL results from microangiopathy which is also associated with DM (1).
Other theories include immunoglobulin deposition, impaired neutrophil migration, collagen abnormalities, inflammatory processes such as antibody-mediated vasculitis and trauma (1,2).
Pathophysiology demonstrates collagen degeneration evolving into granulomatous inflammation with dermal and subcutaneous inflammation.
Fatty deposition and endothelial wall thickening occur later, secondary to inflammation.

There are no known data on prevention.

Older studies have reported >60% prevalence of diabetes in NL patients, whereas newer studies have reported only 15%; therefore, what was previously thought to be a strong association is now being called into question; diabetics with NL may have a higher incidence of microvascular complications such as retinopathy, neuropathy, and nephropathy (1,3).
NL may also be found with thyroid disorders, sarcoid, inflammatory bowel disease, and rheumatoid arthritis (1,3).

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