Eosinophilic granulomatosis with polyangiitis (EGPA) and granulomatosis with polyangiitis (GPA) are rare autoimmune conditions affecting different organs.

Granulomatosis with polyangiitis (GPA) was formerly known as Wegener’s granulomatosis, and Churg-Strauss is now known as eosinophilic granulomatosis with polyangiitis (EGPA) as of 2010. They have distinct immune markers that help doctors differentiate them.

EGPA and GPA are rare autoimmune conditions that cause inflammation in small and medium blood vessels. Both can affect the lungs and sinuses, leading to breathing problems, chronic sinus infections, and unexplained fatigue.

Even though they share some symptoms, they’re not the same. EGPA links to asthma, allergies, and high eosinophil levels. GPA more commonly affects the sinuses, lungs, and kidneys and links with c-ANCA antibodies.

Although EGPA and GPA are both forms of vasculitides, they affect the body in different ways. Here’s a closer look at each condition.

What is EGPA?

Eosinophilic granulomatosis with polyangiitis (EGPA) is a rare but treatable autoimmune condition that causes inflammation in small to medium-sized blood vessels. It mainly affects the lungs, but it can also involve the skin, nerves, and heart.

A key feature of EGPA is the presence of high eosinophil levels. These cells include allergic and inflammatory responses. Most people with the condition also have a history of asthma, chronic sinusitis, or nasal polyps.

EGPA typically develops in three phases; however, not everyone progresses through all of them, and the phases can overlap.

  • Allergic phase: This first phase can present as adult-onset asthma, one of the most common early signs. Many people also develop chronic sinusitis, nasal polyps, or allergic rhinitis during this stage.
  • Eosinophilic phase: In this phase, eosinophils build up in the blood and tissues, causing inflammation. This often affects the lungs, gastrointestinal (GI) tract, skin, or nervous system.
  • Vasculitic phase: This phase occurs when inflamed blood vessels begin to affect the blood flow to major organs. It can develop 3 to 9 years after the onset of asthma. Nerve involvement is common in this stage.

What is GPA?

Granulomatosis with polyangiitis (GPA) is a rare autoimmune disease that causes inflammation in small and medium blood vessels. It can affect the upper respiratory tract, lungs, and kidneys.

Unlike EGPA, GPA doesn’t involve high eosinophil levels. Instead, it strongly links to c-ANCA antibodies, which bind to neutrophils, a type of white blood cell, and trigger inflammation in the blood vessels.

This immune response can damage the tissues in the respiratory tract. In more severe cases, it can also affect the kidneys. For some people, kidney problems can worsen over time and lead to kidney failure, which may require dialysis or a kidney transplant.

EGPA and GPA can both cause breathing problems, sinus symptoms, and general signs of inflammation. The table below compares their symptoms.

Symptom categoryChurg–Strauss or EGPAGPA
Main organs affectedlungs, skin, nerves, heartsinuses, lungs, kidneys
Common early signsasthma, nasal polyps, chronic sinus congestionchronic sinus infections, nosebleeds, and nasal crusting
Skin symptomspurplish spots, rash, tender nodulesulcers, crusting, skin sores, purpura
Lung symptomswheezing, cough, shortness of breathcough, chest pain, coughing up blood
Nerve symptomstingling, numbness, weakness (common)nerve pain or neuropathy (less common)
Kidney involvementrarecommonly can lead to kidney failure

Both conditions may also cause general symptoms such as fatigue, weight loss, joint pain, fever, and muscle aches.

You should consider seeing a doctor if you notice:

It is easy to mistake signs of vasculitis for other conditions, so it’s essential to seek evaluation if symptoms persist.

A rheumatologist, a doctor who specializes in autoimmune and inflammatory conditions, can help determine whether your symptoms suggest vasculitis.

Both EGPA and GPA are autoimmune conditions that result from an overactive immune response, which damages blood vessel walls and leads to inflammation.

Their exact causes are not fully understood, but studies on each condition link genetic factors, infections, and environmental exposures to their development.

Possible causeEGPAGPA
Underlying immune issueoveractive immune response involving eosinophils. Can be autoimmune if ANCA-positiveautoimmune inflammation involving unusual neutrophil activity and granuloma formation
Antibody involvementANCA is present in most people, usually c-ANCA (PR3-ANCA)ANCA present in most people, usually c-ANCA (PR3-ANCA)
Inflammatory cells involvedeosinophils


neutrophils
How damage occurseosinophils build up in tissues and cause inflammation. This can form small lumps called granulomas and lead to vasculitis in small and medium blood vesselsneutrophils cause inflammation that damages the lining of blood vessels and can form granulomas. This leads to vasculitis and can narrow or block blood flow
Common triggersallergies, asthma-related inflammation, infections, medication changes (especially steroid withdrawal)infections, environmental exposures (including smoking), possibly toxins
Genetic risklinks to HLA-DRB4 genelinked to PRTN3 and SERPINA1 genes

Because both conditions are rare and can resemble asthma or other inflammatory disorders, diagnosing EGPA and GPA can be difficult.

Your doctor will take a detailed medical history and perform a physical examination to assess for chronic sinus infections, allergies, skin changes, and any past or current asthma symptoms.

Then they’ll order tests to check for vasculitis and determine whether it’s EGPA or GPA. These may include:

  • Blood tests: To check eosinophil levels, ANCA antibodies (p-ANCA for EGPA and c-ANCA for GPA), and inflammation markers such as erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP).
  • Urinalysis: Checks for blood or protein in the urine, which can be a sign of kidney involvement. Kidney problems are more common in GPA.
  • Imaging: Chest X-rays or CT scans can reveal lung nodules, sinus inflammation, or other abnormalities in the organs.
  • Tissue biopsy: A small tissue sample can confirm vasculitis. In EGPA, the sample can show high levels of eosinophils. In GPA, it usually shows granulomas and damaged blood vessels.

There’s no definitive cure for EGPA or GPA. Treatment aims to lower inflammation, suppress dysregulated immune activity, and protect organs from damage.

Possible treatments include:

  • Corticosteroids: Prednisone or methylprednisolone are usually the first-line drugs used to quickly reduce inflammation and ease breathing or sinus symptoms.
  • Biologic therapies:Mepolizumab (an IL-5 blocker that lowers eosinophils) can help people with EGPA. Rituximab (an anti-B-cell therapy) is commonly used for GPA and may also help some people with EGPA.
  • Immunosuppressants: Doctors may prescribe azathioprine, methotrexate, cyclophosphamide, or mycophenolate mofetil to suppress the immune system, help induce or maintain remission, and lower the risk of relapses. Treatment choice depends on the severity of the disease and the organs involved.
  • Antibiotics or antivirals: Doctors prescribe these medications when they suspect or confirm an infection, or sometimes as prophylaxis for individuals undergoing immunosuppressive therapy. These medications do not treat vasculitis itself.
  • Supportive care: Asthma inhalers, nasal sprays, and other medications can help manage daily symptoms. Doctors also regularly monitor kidney, lung, and heart function in people with GPA to prevent complications.

Most people respond to combination therapy. Many reach remission, though some require long-term maintenance and close follow-up because relapses can occur.

The outlook for EGPA and GPA has improved significantly with early diagnosis and modern treatment. Many people reach remission, although relapses can occur, so long-term follow-up and maintenance therapy are necessary.

For EGPA, about 90% of people survive at least 5 years with corticosteroids and immunosuppressive therapy. Many enter remission, but flare-ups are common. Heart or major nerve involvement links to issues with long-term outlook.

For GPA, evidence suggests that approximately 70% of individuals can achieve remission with treatments such as rituximab or cyclophosphamide. Kidney or lung involvement increases the risk of complications; therefore, regular monitoring is crucial.

EGPA and GPA are rare autoimmune diseases that inflame blood vessels, though they affect different organs and involve different immune markers.

EGPA links to asthma and high eosinophils, whereas GPA typically affects the sinuses, lungs, and kidneys links with c-ANCA antibodies.

Both conditions are treatable when caught early. If you’re noticing symptoms that resemble EGPA or GPA, consider getting a thorough evaluation from your doctor.

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