Necrobiosis Lipoidica

Definition

• Necrobiosis lipoidica is a rare granulomatous skin disorder predominantly affecting the shins, often associated with diabetes mellitus (both type 1 and type 2).

• However, it can also occur in non-diabetic individuals.

• The exact cause is unknown, but it involves inflammatory changes in the dermis around degenerated collagen.

Clinical Features

• Location: Typically on shins (bilaterally), occasionally found elsewhere

• Appearance:

  • Yellow-brown patches with central atrophy

  • Telangiectasia visible, giving a shiny or thinned-out surface

  • Can be round, oval, or irregular in shape

• Symptoms: Generally asymptomatic, though lesions can be tender

• Complications: Susceptible to ulceration (especially after minor trauma) and secondary infection

Differential Diagnosis

• Elastolytic Giant Cell Granuloma (actinic granuloma)

• Necrobiotic Xanthogranuloma (xanthogranulomatous process)

• Sarcoidosis

• Granuloma Annulare (particularly necrobiotic lesions)

Diagnosis

• Largely clinical based on characteristic lesions on the shins in diabetic patients

• Biopsy (if uncertain): Shows granulomatous inflammation around necrotic collagen (helps distinguish from granuloma annulare, rheumatoid nodules)

Management

• Often no treatment needed for mild/asymptomatic lesions.

• Topical Steroids (under occlusion) can help reduce inflammation in active lesions.

• Intralesional Steroids or short courses of systemic corticosteroids if lesions are painful, expanding, or ulcerating.

• Avoid Trauma: Ulcers may develop from minor injury; treat secondary infections promptly if they arise.

• Optimize Diabetes Control: Good glycaemic control may help reduce progression, although evidence is limited.

Notes

• Necrobiosis lipoidica has strong association with diabetes (~ 0.3% of diabetics may develop NL; 15% of NL are non-diabetic).

• Regular review is prudent if lesions are symptomatic or prone to ulceration.