What is eosinophilic granulomatosis with polyangiitis (EGPA, formerly Churg-Strauss)?

Eosinophilic granulomatosis with polyangiitis (EGPA), formerly known as Churg-Strauss, is an extremely rare disease – there are only 2 to 5 new cases a year per 1 million people. EGPA is caused by inflammation (swelling) that occurs in certain types of cells in blood or in tissues. This inflammation causes injury to organ systems – the most commonly involved are the lungs, nose, sinuses, skin, joints, nerves, intestinal tract, heart, and kidneys. A main feature of EGPA is that all patients have a history of asthma and/or allergies.

Almost all people with EGPA have increased numbers of "allergic type" blood cells called eosinophils. Eosinophils are a type of white blood cell that usually make up 5% or less of the total white blood cell count. In EGPA, eosinophils usually make up more than 10% of the total white blood cell count. In addition, most biopsies (tissue samples) contain clusters of cells called "granulomas" that may or may not involve blood vessels. The granulomas often include eosinophils and are therefore called "allergic granulomas." In fact, another name for EGPA is allergic granulomatosis. Some of the most serious cases of EGPA are related to vasculitis.

What is vasculitis?

Vasculitis is a general medical term that means inflammation of the blood vessels. When blood vessels become inflamed, several things can happen:

  • They can grow weak and stretch in size, which can cause an aneurysm to develop. (An aneurysm is an abnormal blood-filled enlargement of a blood vessel.)
  • The walls can become thinner. If they do, the walls can rupture, and blood leaks out into tissue.
  • They can narrow to the point of closing. This can cause damage to the organs from the loss of oxygen and nutrients that were being supplied by the blood.

Who is affected by EGPA?

EGPA can occur in people of all ages, from children to the elderly. The average age that someone is diagnosed is between 35 and 50 years old. EGPA appears to affect men and women equally.

What are the symptoms of eosinophilic granulomatosis with polyangiitis (EGPA)?

Because EGPA can affect several different organ systems, there is a wide range of symptoms.

Patients who have EGPA may feel generally ill and fatigued or have fevers. They may lose their appetite, and lose weight. Other symptoms depend on the organs or diseases involved. For example, patients may have:

  • Shortness of breath from asthma or inflammation in the air sacs and blood vessels of the lung
  • Chest pain from disease that affects the lungs or heart
  • Rashes on the skin
  • Muscle and/or joint pain
  • Increased nasal discharge (runny nose) or facial pain from sinusitis
  • Abdominal pain or blood in the stools from intestinal tract involvement
  • Abnormal feelings, and numbness or loss of strength and feeling from nerve involvement

The patient may have any combination of these symptoms.

Kidney disease caused by EGPA often does not have any symptoms. The patient may not know about inflammation of the kidney until the kidneys begin to stop working. Therefore, patients with any form of vasculitis must have regular urinalyses (examinations of the urine).

What causes EGPA?

The cause of EGPA is unknown. EGPA is not a form of cancer, it is not contagious, and it does not usually run in families.

The immune system plays a role in EGPA. The immune system acts to protect the body against “foreign invaders” (germs, bacteria) that cause infections, disease, and other injuries to the body. Sometimes the immune system does not protect the body as it should.