Is skin bleeding with reddish marks over both legs in a patient with Lupus and ANCA (Antineutrophil Cytoplasmic Antibodies) vasculitis overlap, on Wysolone (Prednisolone) 5 mg and MMF (Mycophenolate Mofetil) 500 mg twice daily, a manifestation of vasculitis or a side effect of steroid use?

Skin Bleeding in Lupus-ANCA Vasculitis Overlap: Vasculitis Relapse vs. Steroid Effect

This presentation most likely represents active cutaneous vasculitis (disease relapse) rather than steroid-induced skin changes, and you should urgently evaluate for systemic vasculitis activity and consider intensifying immunosuppression.

Why This is Likely Vasculitis Relapse

Skin is a commonly involved organ system in ANCA-associated vasculitis, presenting as palpable purpura or infiltrated erythema indicating dermal small-vessel vasculitis 1. The reddish marks with bleeding over both legs are classic for cutaneous vasculitis manifestations 2.

Key Clinical Reasoning:

• Cutaneous vasculitis frequently manifests as palpable purpura or hemorrhagic lesions in ANCA-associated vasculitis, representing active small-vessel inflammation 2
• In lupus-ANCA overlap syndromes, cutaneous vasculitis can be a presenting sign or manifestation of systemic disease activity 3
• The bilateral lower extremity distribution is typical for vasculitic purpura, which gravitates to dependent areas 2

Why 5 mg Prednisolone is Insufficient to Cause This

• 5 mg prednisolone is within the recommended maintenance dose range (5-7.5 mg/day) for AAV in remission 1, 4
• Steroid-induced skin fragility and easy bruising typically occur with chronic high-dose or supraphysiologic steroid use, not maintenance doses of 5 mg 2
• The acute onset of purpuric/hemorrhagic lesions suggests active inflammation rather than chronic steroid effects 2

Critical Concern: Inadequate Maintenance Therapy

Your patient's current MMF dose of 500 mg twice daily (1000 mg/day total) is significantly below the recommended maintenance dose:

• The KDIGO 2024 guidelines recommend MMF 2000 mg/day in divided doses for AAV maintenance therapy 1
• This subtherapeutic dosing substantially increases relapse risk 1
• Patients with relapsing disease should be reinduced, preferably with rituximab 1, 4

Immediate Diagnostic Workup Required

Obtain the following to confirm vasculitis relapse:

• Skin biopsy from the most tender, reddish or purpuric lesion extending to subcutis to identify vasculitic changes 2
• ANCA titers (MPO and PR3) to assess serologic activity 1
• Urinalysis with microscopy looking for dysmorphic red blood cells, red cell casts, and proteinuria indicating renal relapse 1, 4
• Serum creatinine and inflammatory markers (CRP, ESR) to assess systemic activity 1
• Complete blood count to evaluate for cytopenias 5

Management Algorithm

If vasculitis is confirmed:

1. Increase glucocorticoids (oral or intravenous) for acute relapse 1, 4
2. Reinduction therapy, preferably with rituximab, is indicated for relapsing disease 1, 4
3. Optimize MMF dosing to 2000 mg/day if continuing as maintenance agent 1
4. Monitor closely for renal involvement as cutaneous vasculitis may herald systemic relapse 1, 5

Critical Pitfalls to Avoid

• Do not attribute new purpuric lesions to low-dose steroids without excluding active vasculitis - this can lead to catastrophic delays in treatment 2, 3
• Do not wait for biopsy results if clinical presentation strongly suggests vasculitis with systemic features - start treatment immediately 1
• Recognize that cutaneous vasculitis in lupus-ANCA overlap can signal increased severity of underlying disease and risk for poor outcomes 3
• Subtherapeutic immunosuppression (your patient's MMF 1000 mg/day vs. recommended 2000 mg/day) is a major relapse risk factor 1