Immune complex–mediated inflammation of blood vessels occurring as a complication of systemic lupus erythematosus. Typically involves small vessels (skin, capillaries) but can affect medium vessels; large-vessel lupus vasculitis is very rare.
Often signifies a severe SLE flare with risk of organ damage. Lupus vasculitis portends worse prognosis and can be life-threatening (e.g., bowel infarction, pulmonary hemorrhage), so early recognition and aggressive treatment are critical.
Cutaneous vasculitis (most common): presents with skin lesions like palpable purpura, petechiae, nodules, urticaria, bullae, or livedo reticularis; often on legs or fingertips; may cause necrotic ulcers.
Peripheral neuropathy: mononeuritis multiplex (e.g., foot drop) is a classic finding from vasculitic infarction of nerves (vasa nervorum). Can also see symmetric polyneuropathy. CNS vasculitis is rarer but can cause strokes, seizures, or cognitive changes in SLE.
Gastrointestinal: mesenteric vasculitis causes acute abdominal pain, nausea/vomiting, and GI bleeding. Severe cases lead to bowel ischemia, necrosis, or perforation (high mortality).
Pulmonary: diffuse alveolar hemorrhage from pulmonary capillaritis presents with hemoptysis, dyspnea, and new infiltrates (can progress to respiratory failure).
Other rare manifestations include renal vasculitis (distinct from lupus nephritis, with severe hypertension and renal failure), retinal vasculitis (vision loss), or coronary vasculitis (myocardial ischemia).
Maintain a high index of suspicion: in any SLE patient with new focal deficits or ischemic symptoms (e.g., digital gangrene, neuropathy, abdominal pain), consider lupus vasculitis.
Rule out other causes: ensure no infection (fever, cultures) or antiphospholipid syndrome (clots without inflammation) is causing the symptoms. Also review medications for drug-induced vasculitis.
Use diagnostics to confirm: skin or organ biopsy can show leukocytoclastic vasculitis; targeted imaging (e.g., CT angiography for mesenteric vessels, MRI for brain) can identify vasculitic changes.
Treat as a severe SLE flare: initiate prompt immunosuppression (steroids ± other agents) appropriate to the organ involvement and severity.
medium-vessel necrotizing vasculitis (HBV-associated) with mononeuritis and mesenteric ischemia but no SLE or immune complex features
ANCA-associated vasculitis
e.g., granulomatosis with polyangiitis; typically ANCA-positive, can cause similar lung/kidney findings but lacks lupus antibodies
Corticosteroids are first-line: high-dose oral prednisone for moderate disease; IV methylprednisolone pulses for life-threatening vasculitis.
Add immunosuppressants for steroid-sparing and severe cases: e.g., cyclophosphamide or rituximab for severe organ involvement; mycophenolate mofetil, azathioprine, or methotrexate for moderate disease.
Refractory or fulminant cases may require plasmapheresis or IVIG as adjuncts (especially if concurrent diffuse alveolar hemorrhage or severe polyneuropathy). For cutaneous vasculitis, agents like hydroxychloroquine or colchicine can help chronic skin lesions.
Think foot drop + lupus = vasculitis until proven otherwise (mononeuritis multiplex).
Large-vessel vasculitis is exceedingly rare in SLE – if a major artery is involved, consider an unrelated vasculitis (e.g., Takayasu arteritis).
Active lupus vasculitis often comes with low complement (C3, C4) levels due to immune complex consumption.
Don't confuse vasculitis with vasculopathy in SLE: antiphospholipid syndrome causes thrombosis (vascular occlusion) without the inflammation of true vasculitis.
Acute abdomen in SLE (severe pain with possible GI bleeding) → suspect mesenteric vasculitis (can rapidly lead to bowel infarction or perforation).
Mononeuritis multiplex (foot drop, asymmetric neuropathy) in SLE → indicates severe vasculitic involvement of peripheral nerves (requires aggressive therapy).
New stroke or seizure in SLE → consider cerebral vasculitis (distinguish from thrombotic stroke; needs urgent immunosuppression).
SLE flare with unexplained focal symptoms → suspect lupus vasculitis.
Evaluate for infection or other causes (blood cultures, imaging) to rule out mimics (e.g., sepsis, APS thrombosis).
Obtain confirmatory tests: biopsy of affected tissue (skin, nerve) or angiography/CT for organ vasculature to demonstrate vasculitis lesions.
Assess extent/severity: determine if disease is limited (skin only) or systemic (internal organs).
Initiate therapy based on severity → e.g., high-dose steroids + immunosuppressant for organ-threatening vasculitis; monitor closely for improvement or complications.
Young woman with known SLE has acute abdominal pain, melena, and bowel wall thickening on CT → lupus mesenteric vasculitis (risk of infarction).
Patient with SLE develops asymmetric foot drop and sensorimotor loss in one leg → mononeuritis multiplex from lupus vasculitis of vasa nervorum.
SLE patient with new cough, hemoptysis, anemia, and bilateral lung infiltrates → diffuse alveolar hemorrhage due to lupus pulmonary vasculitis.
Case 1
A 25‑year‑old woman with a 3-year history of SLE (on hydroxychloroquine) presents with acute diffuse abdominal pain and bloody diarrhea.
Case 2
A 30‑year‑old woman with SLE develops acute right foot drop and severe burning pain in the left foot.
Cutaneous small-vessel vasculitis (palpable purpura with necrotic lesions) on the legs of a patient with SLE.
