Eosinophilic Granulomatosis with Polyangiitis, formerly Churg-Strauss syndrome
An eosinophil (ee-uh-sin-uh-fil) is a type of white blood cell that is a normal part of your immune system. So, what does this white blood cell have to do with your EGPA?
Normally, eosinophils make up a very small portion of a person's overall white blood cell count. But with EGPA, the percentage of eosinophils is higher than normal. The eosinophil is one of the cell types that may contribute to inflammation, which in turn may cause you to have more EGPA symptoms and flares.
Let's break EGPA down
EGPA, formerly known as Churg-Strauss Syndrome, is a rare chronic condition that causes inflammation of the blood vessels (known as vasculitis). Based on global estimates, EGPA affects only about 5,000 people in the US.*
The main characteristics of EGPA are the development of asthma as an adult, allergic rhinitis (hay fever), growths in the nose, and increased eosinophil count. EGPA may affect multiple parts of the body, but the airways are almost always involved.
The symptoms patients experience depend on which parts of the body are being affected. That's why symptoms can vary from patient to patient. It's likely that only some of the symptoms will be present at any given time.
*This estimate for the US is derived from a global summary prevalence of 14.58 cases per million, based on a US population of approximately 325 million in July 2017.
EGPA is systemic
As a systemic disease, EGPA affects various parts of the body. The symptoms patients experience depend on which organs are being affected. But the most common organs involved are the airways (with asthma), ears, nose, and throat. However, other organs may be affected, including the skin, digestive tract, heart, nerves, and kidneys.
There are 3 phases of EGPA: allergic, eosinophilic, and vasculitic. The phases don't always occur in the same order, they may overlap, and not everyone develops all 3 phases.
You've been bold
Because EGPA is uncommon, the diagnosis can often be delayed. As a patient, you have had to be bold and work to have your symptoms understood. Download your Doctor Discussion Guide to help you have an open and informed discussion with your healthcare provider.
Phase 1 is marked by a variety of allergic reactions, including:
- Asthma: More than 90% of patients have asthma. Patients could have worsening of asthma or develop asthma as an adult. Steroids and other medicines may have been prescribed to help control the patient's symptoms.
- Allergic rhinitis (hay fever): Most EGPA patients have allergic rhinitis, which may include a runny nose, sneezing, and/or nasal itching.
- Sinus/nasal pain and inflammation: Patients may experience facial pain and develop small growths in the nose and sinuses.
Phase 2 is characterized by an abnormally high level of eosinophils in the blood and tissues. The symptoms experienced depend on which part of the body is being affected.
A high number of eosinophils in tissues and blood can affect different body systems. The airways and digestive tract are often affected. If the heart is affected, patients may experience swelling of the legs, irregular heartbeat, or dizziness.
Fever, weakness, muscle and joint pain, and weight loss may occur in this phase as well as in other phases.
The hallmark of Phase 3 is severe blood vessel inflammation (vasculitis). By narrowing the blood vessels, inflammation reduces blood flow to vital organs and tissues throughout the body. Symptoms will vary from patient to patient depending on which organs are affected.
If the skin is affected, the patient will likely develop a rash of purple-colored blood spots (known as purpura). Other kinds of rashes are possible. Purpura usually appears on the legs of EGPA patients. If nerves are affected, patients may experience numbness or difficulties lifting their feet.
Click on the different phases to learn more.
How is EGPA diagnosed?
EGPA can be difficult to diagnose because there are no widely accepted diagnostic criteria. Although there is no specific test for an EGPA diagnosis, the levels and percentage of eosinophils in the blood, in combination with other symptoms, can suggest a Churg-Strauss diagnosis.
In addition, symptoms of EGPA can be similar to other diseases. For all these reasons, a combination of factors may be considered for a diagnosis, including:
- Signs and symptoms
- Physical examination
- Laboratory tests
- Specialized imaging studies
- A biopsy (removal of a sample of tissue or cells)
To confirm the diagnosis of EGPA, patients may be referred to healthcare providers who specialize in treating vasculitis or eosinophilic conditions, such as allergists and immunologists, pulmonologists, and rheumatologists. Others may also be involved.