Patient Basics: Polyarteritis Nodosa

Polyarteritis nodosa (PAN) is a rare disease in which medium-sized arteries become inflamed and damaged. The organs those arteries feed, most often the skin, nerves, kidneys and gut, then get too little blood. Symptoms start with fever, tiredness and weight loss, and can progress to numbness, a lacy skin rash and high blood pressure. It is serious without treatment, but most people do well with medicine.

Key points

• PAN is a type of vasculitis (blood vessel inflammation). It mostly affects adults in middle age.
• Some cases are linked to hepatitis B. A rare inherited form, called DADA2, affects children and young adults.
• Numbness or weakness in a hand or foot, a purple net-like rash, belly pain after meals and new high blood pressure are common signs.
• A biopsy or an imaging test of the arteries confirms it.
• Steroids, sometimes with other medicines that calm the immune system, bring most people into remission.

What causes polyarteritis nodosa

In PAN, the immune system attacks the walls of medium-sized arteries. The walls swell and weaken. Some arteries narrow or close, and others bulge into small balloons (aneurysms) that can bleed. Unlike several other types of vasculitis, PAN usually spares the lungs.

Most of the time, doctors don’t find a trigger. Known causes include:

• Hepatitis B infection. This used to cause many cases. The hepatitis B vaccine has made it much less common.
• Hepatitis C and, rarely, certain blood cancers
• DADA2 (deficiency of adenosine deaminase 2), a genetic condition that can cause a PAN-like illness and early strokes in children and young adults

PAN is not contagious.

Polyarteritis nodosa symptoms

Symptoms depend on which arteries are involved. They often build over weeks to months.

• Whole body: fever, tiredness, weight loss, muscle aches and joint pain
• Nerves: numbness, tingling, burning pain or weakness, often in one hand or foot first, then another. A foot that drops or drags when walking is a common sign.
• Skin: a lacy, purple, net-like pattern (livedo), tender lumps under the skin, small purple spots, or sores on the legs
• Kidneys: new or hard-to-control high blood pressure, and kidney damage
• Gut: belly pain, often after eating, nausea or bleeding
• Testicles: pain or tenderness in men
• Heart and brain: less often, chest pain, heart failure or stroke

A milder form called cutaneous PAN affects only the skin, sometimes with joint and muscle aches. It causes painful lumps and a lacy rash, mostly on the legs.

How it’s diagnosed

No single blood test proves PAN, so doctors piece together several results:

• Blood tests for inflammation (ESR and CRP), blood counts, kidney and liver function, and hepatitis B and C
• ANCA test. This is usually negative in PAN, which helps tell it apart from similar diseases.
• Urine test for blood and protein
• Biopsy. A small piece of skin, nerve or muscle is checked under a microscope for inflamed artery walls.
• Angiography. A CT scan or a catheter X-ray of the arteries can show tiny aneurysms and narrowed spots, often in the kidneys or gut.
• Nerve tests to see which nerves are affected
• Genetic testing for DADA2 in children, young adults, or anyone with early strokes

How polyarteritis nodosa is treated

A rheumatologist (a doctor who treats immune and joint diseases) usually leads care. The plan depends on the cause and on how severe the disease is.

• Steroids such as prednisone calm the inflammation quickly. The dose is lowered slowly over months.
• Cyclophosphamide or another strong immune-suppressing medicine is added when the nerves, kidneys, gut or heart are affected.
• Methotrexate or azathioprine may be used to keep the disease quiet and allow less steroid.
• Hepatitis B-related PAN is treated with antiviral medicines, a short course of steroids and sometimes plasma exchange (filtering the blood).
• DADA2 responds to medicines that block TNF, an immune signal. Standard PAN drugs work less well for it.
• Blood pressure medicine protects the kidneys and heart.

Long-term steroids can thin bones, raise blood sugar and make infections more likely. Your doctor may suggest calcium, vitamin D, bone-protecting medicine and vaccines. Get vaccines before starting treatment when possible.

Living with PAN

With treatment, most people go into remission, often within months. PAN comes back less often than some other types of vasculitis, but regular checkups with blood and urine tests help catch a flare early. Nerve damage can take a year or more to improve, and physical therapy or a brace for foot drop can help in the meantime. Keeping blood pressure in range and not smoking protect your arteries.

When to see a doctor

• Fever, weight loss and tiredness that you can’t explain
• Numbness, tingling or weakness in a hand or foot
• A new purple, lacy rash or painful lumps under the skin
• A flare of symptoms you had before

Call 911 for severe belly pain, blood in vomit or stool, chest pain, or sudden weakness, trouble speaking or face drooping.

Common questions about polyarteritis nodosa

What are the first signs of polyarteritis nodosa?

Early signs are often vague: fever, tiredness, weight loss and aching muscles or joints. Many people then notice numbness or weakness in one hand or foot, or a lacy purple rash on the legs. New high blood pressure can also be an early clue.

Is polyarteritis nodosa curable?

Many people reach a lasting remission and can stop their medicines over time. PAN linked to hepatitis B often clears once the virus is controlled. Doctors keep watch for years because the disease can return, and some damage, such as nerve injury, may not fully heal.

Is polyarteritis nodosa inherited?

Usually not. Most PAN has no known cause and doesn’t run in families. The exception is DADA2, a gene condition passed down when both parents carry a change in the same gene. Doctors consider testing for it in children, young adults and people with early strokes.

Questions to ask your doctor

• Which organs are affected in my case?
• Have I been tested for hepatitis B and C?
• How long will I need steroids, and how can I limit side effects?
• What signs of a flare should I watch for?
• Which vaccines should I get before or during treatment?

Learn more

• Polyarteritis nodosa (MedlinePlus, U.S. National Library of Medicine)
• Vasculitis (National Heart, Lung, and Blood Institute)

This guide is general information and doesn’t replace advice from your own doctor. Last updated October 2026.