Vasculitis: Understanding Autoimmune Inflammation of Blood Vessels

Vasculitis isn't just one disease-it's a group of rare but serious conditions where the immune system turns against the body’s own blood vessels. Instead of protecting you, your immune system attacks the walls of arteries, veins, and capillaries, causing inflammation, narrowing, or even blockages. This can cut off blood flow to vital organs like the kidneys, lungs, nerves, or skin. Left untreated, it can lead to tissue death, aneurysms, or organ failure. What makes vasculitis tricky is that its symptoms often mimic more common illnesses-fatigue, joint pain, or a rash-so it can take months to get the right diagnosis.

How Vasculitis Damages Blood Vessels

When inflammation hits a blood vessel, it doesn’t just swell up. The vessel wall gets attacked by immune cells, leading to thickening, scarring, or even holes. In severe cases, the middle layer of the vessel (the media) breaks down, which can cause the wall to stretch and form an aneurysm. If the vessel narrows too much, blood can’t get through. If it bursts, internal bleeding follows. This damage happens in small vessels like capillaries in the kidneys or lungs, or in large arteries like the aorta or temporal arteries in the head.

The type of vasculitis depends on which size of vessel is affected. Large-vessel vasculitis targets the aorta and its major branches. Giant cell arteritis, which mostly affects people over 50, often attacks the arteries in the temples, causing severe headaches, jaw pain when chewing, or even sudden vision loss. Takayasu arteritis, another large-vessel form, is more common in younger women and can cause arm pain or weak pulses in the wrists.

Medium-vessel vasculitis includes polyarteritis nodosa and Kawasaki disease. Kawasaki disease, mostly seen in children under 5, can lead to coronary artery aneurysms in 20-25% of untreated cases. That’s why early treatment with IV immunoglobulin and aspirin is critical in kids.

Small-vessel vasculitis is the most common group and includes ANCA-associated diseases like granulomatosis with polyangiitis (GPA), microscopic polyangiitis (MPA), and eosinophilic granulomatosis with polyangiitis (EGPA). These often hit the kidneys first-sometimes without any warning signs. That’s why doctors test urine for blood or protein even if a patient feels fine.

Recognizing the Symptoms

There’s no single symptom of vasculitis. It depends on which organs are involved. Many people report fatigue, fever, weight loss, or night sweats-signs that could be mistaken for the flu or chronic stress. But if you have these along with:

• Purple or red spots, bumps, or ulcers on the skin
• Joint pain or muscle aches that don’t go away
• Shortness of breath or coughing up blood
• Numbness, tingling, or weakness in hands or feet
• Stomach pain, diarrhea, or bloody stools
• Severe headaches or vision changes (especially over age 50)

-it’s time to suspect vasculitis. The American College of Rheumatology warns that kidney damage can happen silently. A simple urine test might show red blood cells before you feel any pain. That’s why early screening matters.

How Doctors Diagnose It

There’s no single blood test for vasculitis. Diagnosis is a puzzle made of clinical signs, lab results, imaging, and biopsy. Key clues include:

• Elevated ESR (erythrocyte sedimentation rate) over 50 mm/hr or CRP (C-reactive protein) above 5 mg/dL
• Positive ANCA (anti-neutrophil cytoplasmic antibodies): c-ANCA (targeting proteinase-3) is 80-90% specific for GPA; p-ANCA (targeting MPO) often links to MPA or EGPA
• Abnormal kidney function tests or protein in urine

Imaging like CT angiography or MRI can show inflamed arteries, especially in large-vessel cases. But the gold standard is a tissue biopsy. For skin lesions, a small sample can show leukocytoclastic vasculitis-immune cells and broken-down nuclei around small vessels. For kidney involvement, a biopsy confirms crescentic glomerulonephritis, a telltale sign of MPA.

Doctors also use the Five Factor Score to predict severity in polyarteritis nodosa. It looks at whether there’s kidney, heart, gastrointestinal, or neurological involvement. Patients with no major organ damage have a 95% five-year survival rate. Those with two or more factors drop to 50%-highlighting how urgent treatment is.

Treatment: From Steroids to Targeted Therapies

Treatment starts with stopping the immune system’s attack. For severe cases, high-dose corticosteroids like prednisone (0.5-1 mg/kg/day) are used right away. But steroids alone aren’t enough-they come with serious side effects: bone loss, diabetes, weight gain. That’s why they’re paired with stronger immunosuppressants.

For ANCA-associated vasculitis, cyclophosphamide was the standard for years. Now, rituximab (a drug that wipes out B-cells) is often preferred because it’s just as effective and has fewer long-term risks. The 2022 ACR guidelines added avacopan, a new oral drug that blocks a protein called C5a. In the CLEAR trial, patients on avacopan plus low-dose steroids cut their total steroid exposure by about 2,000 mg over a year-meaning less bone damage and fewer infections.

For giant cell arteritis, steroids are still first-line. But since many patients need them for years, tocilizumab (an IL-6 inhibitor) is now approved as an add-on. It helps reduce steroid doses and lowers relapse rates. In Kawasaki disease, IVIG and aspirin are lifesavers. For Buerger’s disease (thromboangiitis obliterans), nothing works unless you quit smoking completely. Even one cigarette a day can make treatment useless.

Prognosis and Long-Term Management

With treatment, 80-90% of people with ANCA vasculitis go into remission. But here’s the catch: about half of them relapse within five years. That’s why long-term monitoring is non-negotiable. Regular blood tests, urine checks, and imaging are part of life after diagnosis.

Patients with giant cell arteritis often need steroids for 1-2 years or longer. Some develop jaw claudication or vision loss before diagnosis, and those changes may be permanent. That’s why early recognition matters. For children with Kawasaki disease, follow-up echocardiograms are critical for years to check for coronary artery changes.

The good news? Survival rates have improved dramatically. In the 1980s, 50% of GPA patients died within five years. Today, with modern treatments, 90% are alive after five years. New drugs like mepolizumab (for EGPA) and abatacept (for GCA) are showing promise in trials, cutting relapse rates by half in early studies.

Why Early Diagnosis Is Everything

The average delay in diagnosing vasculitis? Six to twelve months. Patients often see multiple doctors before someone connects the dots. A rash? Maybe eczema. Fatigue? Stress. Kidney issue? Maybe diabetes. But if you have unexplained symptoms across multiple systems, especially with elevated inflammation markers, ask about vasculitis.

As Dr. Peter A. Merkel from Hospital for Special Surgery says: “Getting an accurate diagnosis by a rheumatologist is important because, although these diseases are treatable, early intervention may be needed to avoid significant, irreversible organ damage.”

There’s no cure yet. But vasculitis is manageable. With the right team, the right drugs, and consistent follow-up, most people live full lives. The key is not waiting for symptoms to get worse. If something feels off-especially if it’s new, persistent, and multi-system-get checked. Your blood vessels are counting on it.