Necrobiosis lipoidica — exam essentials

• Chronic granulomatous skin disorder, classically on shins
• Shiny yellow‑brown atrophic plaques with violaceous/red border and telangiectasia
• Strong association with diabetes mellitus (type 1 and 2). Can occur without diabetes. More common in women

Key clinical features

• Starts as red papules or plaques that enlarge and become atrophic and shiny centrally
• Skin becomes thin and prone to trauma
• Ulceration in up to one‑third of cases; can be painful and slow to heal

Diagnosis

• Clinical diagnosis when classic appearance present
• Skin biopsy if uncertain: granulomatous inflammation around degenerated collagen (necrobiosis)
• Screen for diabetes if not known (fasting glucose or HbA1c)

Management

• General: protect from trauma; compression if venous disease; optimize glycaemic control; smoking cessation
• First line: potent topical corticosteroids or intralesional steroids to active borders
• Alternatives for refractory disease (specialist): calcineurin inhibitors, systemic agents, phototherapy, or laser
• Observation is reasonable if asymptomatic and stable

Complications and notes

• Ulceration and secondary infection are the main morbidities
• Cosmetic impact and potential scarring