Systemic Lupus Erythematosus (SLE) is a chronic autoimmune disease where the immune system mistakenly attacks the body’s healthy tissues and organs. This systemic attack can impact nearly any part of the body. Vasculitis is the inflammation of blood vessel walls, causing them to narrow, thicken, or scar. Lupus vasculitis is a severe manifestation of SLE where autoimmune activity specifically targets blood vessels throughout the body. This complication affects a significant percentage of people with SLE, potentially damaging vessels supplying the skin, nerves, and major organs. The resulting vessel damage impairs blood flow, which can lead to tissue damage or organ failure. Recognizing lupus vasculitis is important because its presence often signifies highly active and potentially life-threatening disease requiring immediate and aggressive intervention.
The Mechanism of Lupus Vasculitis
The underlying cause of lupus vasculitis is the misdirected immune response characteristic of SLE. The body produces autoantibodies that bind to self-antigens, forming circulating structures known as immune complexes. These antigen-antibody clusters become trapped within the walls of blood vessels. Once deposited, these immune complexes activate the complement system, triggering a severe inflammatory reaction. This process attracts inflammatory cells, such as neutrophils, which release destructive enzymes that damage the vessel wall. The resulting inflammation often leads to a condition called leukocytoclastic vasculitis, commonly seen in the skin’s small vessels.
Lupus vasculitis is categorized by the size of the vessels affected, most frequently small vessels like capillaries and venules, but the condition can also target medium-sized arteries. Damage causes vessel walls to swell and narrow, restricting blood flow and leading to localized tissue ischemia, or lack of oxygen. This reduced blood supply is the mechanism responsible for the patient’s symptoms, and the type of vessel involved determines the specific organ system affected.
Clinical Presentation and Affected Systems
The physical signs of lupus vasculitis are highly diverse, depending on the location and caliber of the inflamed blood vessels. Skin manifestations are the most common presentation, often appearing as palpable purpura—small, raised purple or red spots that do not blanch when pressed. Other cutaneous signs include skin ulcers, particularly around the ankles, and livedo reticularis, a mottled, lace-like purple discoloration caused by interrupted blood flow to the small vessels.
When vessels supplying the peripheral nerves are involved, a condition called mononeuritis multiplex can develop. This involves damage to two or more separate nerve areas, leading to asymmetrical weakness, pain, numbness, or tingling in the extremities. Inflammation in the small vessels of the central nervous system can be particularly severe, potentially causing symptoms like seizures, severe headaches, or stroke-like events.
Inflammation of the arteries supplying the digestive tract, known as lupus mesenteric vasculitis, can result in acute and severe abdominal pain. This is a life-threatening complication that can cause bowel wall ischemia, necrosis, and perforation if left untreated. Lung involvement can manifest as diffuse alveolar hemorrhage, a serious condition where bleeding occurs into the air sacs, presenting with sudden shortness of breath and coughing up blood. When the small vessels in the kidneys are affected, it can exacerbate lupus nephritis, leading to rapid deterioration of kidney function and severe renal insufficiency.
Confirming the Diagnosis
The diagnostic process begins with a comprehensive physical examination and a detailed review of the patient’s symptoms. Laboratory blood tests are an initial step, typically showing elevated markers of systemic inflammation, such as a high erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP). Furthermore, tests for autoantibodies, like antinuclear antibodies (ANA) and anti-double-stranded DNA (anti-dsDNA), confirm the underlying SLE diagnosis.
Since lupus vasculitis is an immune complex-mediated disease, blood tests often reveal low levels of complement proteins C3 and C4, which are consumed during inflammation. The most definitive way to confirm the diagnosis and distinguish it from other conditions is by obtaining a tissue biopsy from an affected organ, such as the skin or a peripheral nerve. A pathologist examines the tissue for hallmark signs of inflammation and destruction within the vessel walls, including the presence of immune complexes and inflammatory cell infiltration.
For cases involving larger or deeper vessels, medical imaging studies are required. Angiography, which involves injecting a contrast dye, can reveal characteristic narrowing, blockages, or aneurysms in arteries supplying organs like the intestines or brain. Computed tomography (CT) or magnetic resonance imaging (MRI) scans also help assess the extent of organ damage resulting from compromised blood flow.
Treatment Strategies and Management
The treatment of lupus vasculitis focuses on rapidly suppressing the immune system to halt inflammatory damage to the vessel walls. The initial phase for moderate to severe disease often involves high-dose corticosteroids, such as intravenous methylprednisolone pulse therapy. These anti-inflammatory drugs work quickly to reduce systemic inflammation and control acute symptoms.
After initial high-dose therapy, the dose transitions to high-dose oral prednisone, which is gradually tapered as the disease comes under control. To achieve long-term remission and minimize the negative side effects of prolonged steroid use, immunosuppressive agents are introduced. The choice of agent depends on the severity of the vasculitis and the organs involved.
Common immunosuppressive medications include cyclophosphamide for life-threatening, organ-damaging disease, or azathioprine and mycophenolate mofetil for maintenance therapy. These drugs work by reducing the production of immune cells and autoantibodies responsible for vessel inflammation. Supportive care measures are also integrated into the management plan, including pain management, wound care for skin ulcers, and medications to manage associated complications like high blood pressure. Regular monitoring through blood tests and imaging is necessary to assess treatment effectiveness and adjust medication doses to prevent disease flares while minimizing drug toxicity.