Polyarteritis nodosa is an autoimmune disease (immune system attacking its own body) characterized by spontaneous inflammation of the arteries (arteritis) of the body. Because arteries are involved, the disease can affect any organ of the body, most commonly muscles, joints, intestines, nerves, kidneys, and skin.

Treatment is directed toward decreasing the inflammation of the arteries by suppressing the immune system. Medications used to treat polyarteritis nodosa include high-dose intravenous and oral cortisone medications such as prednisone, as well as immunosuppressive drugs such as cyclophosphamide (Cytoxan) or azathioprine (Imuran).