A rare disease that causes swelling, also called inflammation, of small blood vessels.

Granulomatosis with polyangiitis mainly affects blood vessels in the nose, sinuses, throat, lungs and kidneys. It slows blood flow to organs and tissues, causing damage. The cause isn't clear, but the immune system may play a role.

Symptoms of granulomatosis with polyangiitis can vary widely. Early on, it can cause general symptoms such as fever, tiredness and muscle aches. Later symptoms depend on what parts of the body are affected.

The main treatment for granulomatosis with polyangiitis is medicine to help lessen the immune system response and lower inflammation of the blood vessels. Some people need to take medicine over the long term.

Treatments include drugs that suppress the immune system and monitoring for recurring symptoms.