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Necrobiosis Lipoidica

  • ICD-10 L92.1
  • Last reviewed:

Necrobiosis lipoidica (NL) is a rare, chronic inflammatory skin condition characterized by shiny, yellowish-brown plaques with telangiectasia (visible blood vessels) that typically appear on the shins.

The Basics

What is it?

Necrobiosis lipoidica (NL) is a rare, chronic inflammatory skin condition characterized by shiny, yellowish-brown plaques with telangiectasia (visible blood vessels) that typically appear on the shins. The condition involves degeneration of collagen in the dermis (deeper layer of skin) and is strongly associated with diabetes mellitus, occurring in approximately 0.3-1% of diabetic patients. Despite this association, about one-third of patients with necrobiosis lipoidica do not have diabetes.

Who is affected?

Necrobiosis lipoidica demonstrates specific demographic patterns:

  • Age distribution: Can occur at any age but most commonly develops between 30-40 years
  • Gender predilection: Women are affected 3 times more frequently than men
  • Diabetes association: 60-70% of patients have diabetes mellitus (usually Type 1)
  • Prevalence: Rare condition affecting approximately 0.3% of diabetic patients
  • Family history: Occasional familial clustering reported

What are the clinical features?

The condition presents with characteristic skin changes:

Visual characteristics:

  • Initial lesions: Small, firm, red-brown papules or nodules
  • Evolved plaques: Enlarging to form irregular, well-demarcated plaques
  • Central appearance: Yellow-brown, waxy, atrophic center
  • Border characteristics: Raised, red-violet edge
  • Surface features: Shiny, translucent appearance with visible blood vessels
  • Size: Typically 1-3 cm but can become much larger

Location:

  • Most common: Bilateral pretibial areas (shins) in 85% of cases
  • Other sites: Forearms, hands, trunk, face (less common)
  • Distribution: Often bilateral and roughly symmetrical

How is it diagnosed?

Diagnosis is primarily clinical but may require confirmation:

  • Clinical examination: Recognition of characteristic yellowish plaques on shins
  • Dermoscopy: Shows comma-shaped vessels and yellow structureless areas
  • Skin biopsy: May be performed if diagnosis uncertain, shows palisading granulomas
  • Blood tests: Glucose testing to screen for diabetes
  • Differential diagnosis: Must distinguish from granuloma annulare, diabetic dermopathy

What treatment options are available?

Treatment can be challenging as the condition is often resistant:

Topical therapies:

  • High-potency corticosteroids: First-line treatment, applied under occlusion
  • Tacrolimus ointment: Alternative for facial lesions or steroid-resistant cases
  • Topical tretinoin: May help with early lesions

Systemic treatments:

  • Pentoxifylline: Improves blood flow, 400mg three times daily
  • Aspirin and dipyridamole: Antiplatelet agents may help
  • Systemic corticosteroids: For severe or rapidly progressive cases
  • Hydroxychloroquine: May be beneficial in some patients

Other interventions:

  • Intralesional corticosteroids: Injected into active borders
  • Phototherapy: PUVA or narrowband UVB
  • Laser therapy: Pulsed dye laser for telangiectasia
  • Wound care: Important for ulcerated lesions (occurs in 35% of cases)

What is the prognosis?

The course of necrobiosis lipoidica is variable:

  • Chronic course: Lesions typically persist for years
  • Ulceration risk: 35% of lesions may ulcerate, particularly after trauma
  • Scarring: Healed lesions often leave atrophic scars
  • Diabetes relationship: Glycemic control doesn't consistently improve skin lesions
  • Quality of life: Cosmetic concerns and potential for ulceration affect daily life
  • Spontaneous resolution: Rare but can occur after many years

Prevention focuses on protecting affected areas from trauma, maintaining good diabetes control if present, and early treatment of new lesions. Regular monitoring is important to detect and treat complications such as ulceration promptly.

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Epidemiology

Necrobiosis lipoidica (NL) represents a rare granulomatous disorder with distinct epidemiological characteristics:

Incidence and Prevalence:

  • General population: 0.3 per 100,000 person-years
  • Diabetic population: 0.3-1.2% prevalence
  • Type 1 diabetes: Higher prevalence (approximately 1%)
  • Type 2 diabetes: Lower prevalence (approximately 0.3%)
  • Non-diabetic cases: 25-40% of all NL patients

Demographic Distribution:

  • Female-to-male ratio: 3:1
  • Age of onset: Bimodal distribution with peaks in 3rd-4th decade and childhood
  • Pediatric cases: 10-20% of cases begin before age 20
  • Ethnic variations: No significant racial predilection documented

Aetiology and pathogenesis

The pathogenesis of necrobiosis lipoidica remains incompletely understood:

Proposed Mechanisms:

  1. Microangiopathy theory:

    • Diabetic microvessel disease leading to tissue ischemia
    • Immune complex deposition in vessel walls
    • Platelet aggregation abnormalities

  2. Primary collagen abnormality:

    • Abnormal collagen cross-linking
    • Increased collagenase activity
    • Glycosylation of dermal proteins

  3. Immunological factors:

    • Delayed-type hypersensitivity reaction
    • Abnormal neutrophil migration
    • Elevated TNF-α and other inflammatory cytokines

Histopathological Features:

  • Early lesions: Neutrophilic infiltrate, vascular changes
  • Established lesions:
    • Palisading granulomas throughout dermis
    • Necrobiosis (degeneration) of collagen
    • Horizontal layered appearance ("layer cake" pattern)
  • Late lesions: Sclerosis, loss of elastic fibers

Clinical presentation

Classical Presentation:

  • Morphology progression:
    1. Initial: Erythematous papules or nodules
    2. Intermediate: Coalescence into plaques
    3. Established: Yellow-brown atrophic center with violaceous rim
    4. Late: Sclerodermatous changes, possible ulceration

Clinical Variants:

  • Ulcerative NL: 13-35% of cases, poor healing tendency
  • Perforating NL: Transepidermal elimination of necrobiotic material
  • Nodular NL: Predominantly nodular without typical plaques
  • NL of face and scalp: Rare, may mimic other conditions

Associated Conditions:

  • Diabetes mellitus: 60-75% association
  • Thyroid disease: 15% of patients
  • Inflammatory bowel disease: Case reports
  • Rheumatoid arthritis: Occasional association
  • Sarcoidosis: Rare association

Diagnosis

Clinical Assessment:

  • History taking:
    • Diabetes status and control
    • Trauma history to affected areas
    • Previous treatments attempted
    • Family history of diabetes or NL

Laboratory Investigations:

  • Metabolic screening:
    • Fasting glucose, HbA1c
    • Oral glucose tolerance test if indicated
    • Lipid profile
  • Thyroid function tests
  • Complete blood count
  • Inflammatory markers: ESR, CRP (usually normal)

Imaging and Special Tests:

  • Dermoscopy findings:

    • Comma-shaped vessels
    • Linear irregular vessels
    • Yellow structureless areas
    • White network-like structures

  • Histopathology:

    • Horizontal alternating layers of inflammation and sclerosis
    • Palisading histiocytes around necrobiotic collagen
    • Plasma cells prominent in dermis
    • Direct immunofluorescence negative

Management

First-line Therapies:

  1. Topical corticosteroids:

    • Class I (super-potent) under occlusion
    • Duration: 6-8 weeks initial trial
    • Maintenance: Intermittent application

  2. Intralesional corticosteroids:

    • Triamcinolone acetonide 2.5-5 mg/mL
    • Inject at active borders monthly
    • Risk of further atrophy

Second-line Systemic Therapies:

  1. Pentoxifylline:

    • Dose: 400mg TID
    • Mechanism: Improves microcirculation
    • Response rate: 50-70%
    • Duration: Minimum 6 months trial

  2. Antiplatelet agents:

    • Aspirin 40-325mg daily
    • Dipyridamole 75mg TID
    • Combination therapy possible

  3. Hydroxychloroquine:

    • Dose: 200-400mg daily
    • Monitor for retinal toxicity
    • May combine with pentoxifylline

Third-line and Experimental Therapies:

  • Biologics: TNF-α inhibitors (infliximab, etanercept)
  • JAK inhibitors: Case reports of success
  • Cyclosporine: 3-5mg/kg/day
  • Mycophenolate mofetil: 1-2g daily
  • Fumaric acid esters: European experience
  • Photodynamic therapy: Limited data

Complications

Ulceration (35% of cases):

  • Risk factors: Trauma, poor circulation, location on shin
  • Management:
    • Wound care with appropriate dressings
    • Compression therapy if venous insufficiency
    • Consider hyperbaric oxygen
    • Surgical debridement if needed
    • Skin grafting for non-healing ulcers

Squamous Cell Carcinoma:

  • Rare complication: Case reports in chronic ulcerated lesions
  • Surveillance: Regular monitoring of non-healing ulcers
  • Biopsy indication: Any suspicious changes

Prognosis

Natural History:

  • Duration: Typically chronic over years to decades
  • Spontaneous resolution: 13-19% of cases after 6-12 years
  • Koebnerization: New lesions at sites of trauma

Monitoring Protocol:

  • Frequency: Every 3-6 months initially, then annually
  • Assessment:
    • Disease activity and progression
    • Ulceration development
    • Treatment response
    • Glycemic control in diabetics
  • Photography: Document changes over time

Quality of Life Considerations:

  • Psychological impact: Body image concerns
  • Physical limitations: Pain, ulceration affecting mobility
  • Social implications: Visible lesions affecting relationships
  • Patient education: Trauma prevention, realistic expectations

Recent advances

Emerging Therapies:

  • JAK-STAT inhibitors: Promising case reports
  • Anti-IL-17 agents: Under investigation
  • Stem cell therapy: Experimental approach

Pathogenesis Research:

  • Genetic studies: Investigating susceptibility factors
  • Biomarker development: Predictors of treatment response
  • Microbiome studies: Role in wound healing

References

  1. Reid SD, Ladizinski B, Lee K, et al. Update on necrobiosis lipoidica: a review of etiology, diagnosis, and treatment options. J Am Acad Dermatol. 2013;69(5):783-791.

  2. Hashemi DA, Brown-Joel ZO, Tkachenko E, et al. Clinical Features, Association with Diabetes, and Treatment Response in Patients with Necrobiosis Lipoidica. JAMA Dermatol. 2019;155(10):1167-1173.

  3. Erfurt-Berge C, Dissemond J, Schwede K, et al. Updated results of 100 patients on clinical features and therapeutic options in necrobiosis lipoidica in a retrospective multicentre study. Eur J Dermatol. 2015;25(6):595-601.

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