What Is Polyarteritis Nodosa?

Your arteries and veins take blood to and from your heart and organs. Your body needs this oxygen-rich blood to keep you healthy.

Polyarteritis nodosa (PAN) is a rare disease that makes your blood vessels swell. It can affect the blood vessels that go to almost every part of your body, including your heart, kidneys, and intestines. It can keep these and other organs from getting enough blood.

PAN is very treatable -- especially if it's caught early. Medication can protect your blood vessels from damage and help with your symptoms.

Most people get it in their 40s or 50s, but it can affect people of all ages. Men are more likely than women to get it.


Signs of PAN include:

You also might have other symptoms, depending on which organs are affected:


Joints and muscles:

Kidneys :

Digestive tract:


  • Numbness or tingling in your arms, hands, legs, and feet
  • Seizures
  • Weakness in your hands or feet

Skin (often on your legs):

  • Bumps
  • Changes in skin color
  • Purple spots, called purpura
  • Rash
  • Sores

Eyes :

  • Swelling in the white part of your eye

Genitals (in men):

  • Painful or tender testicles


PAN is an autoimmune disease. Your immune system mistakes your blood vessels for a virus or other foreign invader and attacks them. This makes them inflamed, a condition called vasculitis.

When a blood vessel is inflamed, it swells and stretches. As it stretches, its walls get thinner and thinner, like a balloon. This is called an aneurysm. Eventually, the blood vessel walls can stretch so much they burst open.

Swelling can also narrow blood vessels. They can get so narrow that blood doesn't have enough room to move through them. When that happens, less blood gets to your organs.

Most of the time, doctors don't know what causes this immune attack. In a small number of people, it may be triggered by hepatitis B or C. Other infections, like strep or staph, might also cause PAN.



Your doctor will ask about your symptoms and give you an exam. She may test your blood or urine to see how well your kidneys and other organs work and see if you've been infected with hepatitis B or C.

She also might want to do imaging tests to look for damage to your blood vessels or organs:

  • X-ray: This uses radiation in low doses to make images of structures inside your body.
  • CT (computed tomography) scan: Powerful X-rays are taken at different angles and put together to make detailed pictures inside your body.
  • MRI (magnetic resonance imaging): This uses powerful magnets and radio waves to make pictures of organs and structures inside your body.

An arteriogram (also called angiogram) is another test for PAN. Your doctor injects a dye into your bloodstream. Then an X-ray is taken of the blood vessels to look for problem areas. Most often, this test looks at blood vessels that go to your gut and kidneys.

A biopsy can show if there's swelling in your blood vessels. Your doctor will take a small piece of tissue from the wall of your blood vessel and check it under a microscope for signs of PAN.


Being treated as soon as possible can protect your blood vessels and put your PAN into remission, a state in which you don't have any signs of the disease.

You'll take medicine to stop your immune system from attacking your blood vessels and bring down swelling. This might be a corticosteroid drug, such as prednisone or prednisolone.

If your PAN is very serious, you also might get a drug like cyclophosphamide (Cytoxan), methotrexate (Trexall), or azathioprine (Imuran) to help calm your immune system.

Once your symptoms get better, your doctor will lower your dose of medicines. Eventually, you should be able to stop taking them.

If you have hepatitis B or C, you'll also get antiviral drugs. And if you have high blood pressure, you'll take medication for that, too.

See your doctor for regular follow-ups because the disease can come back. You'll want to stop any new damage to your blood vessels as soon as it starts.

WebMD Medical Reference Reviewed by Carol DerSarkissian on October 28, 2018



Cleveland Clinic: "Polyarteritis Nodosa."

National Organization for Rare Disorders: "Polyarteritis Nodosa."

The Johns Hopkins Vasculitis Center: "Polyarteritis Nodosa."

Vasculitis Foundation: "Polyarteritis Nodosa."

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