Published: 18 Jun 2025

ICD9: 446.4      ICD10: M31.30      ICD11: 4A44.A2

Okay, let's clarify some terminology first.
Churg-Strauss syndrome is now more correctly called Eosinophilic Granulomatosis with Polyangiitis (EGPA). Wegener's Granulomatosis is now known as Granulomatosis with Polyangiitis (GPA). They are distinct conditions, though both are types of vasculitis. Therefore, the term "Churg-Strauss syndrome (Wegener's Granulomatosis)" is incorrect and misleading.

Let's break down what EGPA is, and then briefly mention GPA for clarity.

Eosinophilic Granulomatosis with Polyangiitis (EGPA)

EGPA is a rare autoimmune disorder that causes inflammation of small and medium-sized blood vessels (vasculitis). It is characterized by three main features:

1. Asthma: Usually adult-onset and can be severe. This is often the earliest and most prominent symptom.

2. Eosinophilia: Abnormally high levels of eosinophils (a type of white blood cell) in the blood and tissues. Eosinophils are normally involved in fighting parasites and allergies, but in EGPA, they become overactive and contribute to inflammation.

3. Vasculitis: Inflammation of the blood vessels. This can affect various organs and systems, leading to a wide range of symptoms.

How EGPA Works:

In EGPA, the immune system mistakenly attacks the blood vessels, causing inflammation and damage. The high levels of eosinophils contribute to this inflammatory process. The inflammation can narrow the blood vessels, restricting blood flow to organs and tissues. This can lead to tissue damage and organ dysfunction.

Symptoms of EGPA:

The symptoms of EGPA can vary widely depending on which organs are affected, but often occur in phases:

Prodromal Phase (Early Stage):
Asthma (often worsening)
Allergic rhinitis (hay fever)
Sinusitis
Nasal polyps

Eosinophilic Phase:
High eosinophil counts in the blood
Eosinophilic infiltration of tissues (e.g., lungs, heart, gastrointestinal tract)

Vasculitic Phase:
Systemic symptoms: Fever, fatigue, weight loss, night sweats
Skin: Rash, nodules, purpura (small, flat hemorrhages under the skin)
Nervous system: Peripheral neuropathy (nerve damage causing numbness, tingling, pain, weakness, usually in hands and feet), mononeuritis multiplex (damage to multiple individual nerves)
Lungs: Cough, shortness of breath, wheezing, lung infiltrates
Heart: Cardiomyopathy (weakening of the heart muscle), pericarditis (inflammation of the sac surrounding the heart)
Kidneys: Glomerulonephritis (inflammation of the kidney filters), less common and usually less severe than in GPA
Gastrointestinal: Abdominal pain, diarrhea, bleeding

Diagnosis of EGPA:

Diagnosis of EGPA is based on a combination of factors:

Clinical symptoms: The presence of asthma, eosinophilia, and vasculitis-related symptoms.
Blood tests: Elevated eosinophil count, presence of certain antibodies (e.g., anti-neutrophil cytoplasmic antibodies or ANCA, although they are less common in EGPA than in GPA and often have a different specificity).
Biopsy: A tissue biopsy (usually from the affected organ, such as lung or skin) showing evidence of vasculitis and eosinophilic infiltration.
Imaging studies: Chest X-ray or CT scan to assess lung involvement.

Treatment of EGPA:

The goal of treatment is to suppress the immune system and reduce inflammation. Treatment typically involves:

Corticosteroids (e.g., prednisone): The mainstay of treatment for reducing inflammation.
Immunosuppressants (e.g., cyclophosphamide, azathioprine, methotrexate): Used to further suppress the immune system and reduce the need for high doses of corticosteroids.
Biologic agents (e.g., mepolizumab, benralizumab): These medications target eosinophils and have been shown to be effective in treating EGPA, especially in reducing asthma exacerbations and corticosteroid dependence.
Rituximab: This medication targets B cells, another type of immune cell involved in the disease.

Prognosis of EGPA:

With early diagnosis and treatment, the prognosis for EGPA can be good. However, EGPA can be a chronic and relapsing condition, and some patients may experience long-term complications.

Granulomatosis with Polyangiitis (GPA)

GPA (formerly Wegener's Granulomatosis) is another type of vasculitis that affects small and medium-sized blood vessels. However, it differs from EGPA in several key aspects:

Asthma and eosinophilia are *not* typical features of GPA.
GPA primarily affects the respiratory tract (nose, sinuses, lungs) and kidneys.
GPA is more strongly associated with specific ANCA antibodies (usually c-ANCA or PR3-ANCA).
GPA often causes granulomas (clusters of inflammatory cells) in the affected tissues.

The symptoms of GPA can include:

Sinusitis
Nasal congestion
Nosebleeds
Cough
Shortness of breath
Hemoptysis (coughing up blood)
Kidney problems
Joint pain
Skin rash

GPA is also treated with corticosteroids and immunosuppressants, but the specific medications and treatment approaches may differ from those used for EGPA.

In summary:

EGPA (formerly Churg-Strauss syndrome) is characterized by asthma, eosinophilia, and vasculitis.
GPA (formerly Wegener's Granulomatosis) primarily affects the respiratory tract and kidneys and is associated with specific ANCA antibodies, but typically *lacks* asthma and eosinophilia.

It's crucial to differentiate between these two conditions because their clinical features, underlying mechanisms, and treatment approaches differ. They are both serious conditions that require prompt diagnosis and management by a specialist.