Churg-Strauss Syndrome: Symptoms, Causes, and Diagnosis

If you’ve ever had asthma that just won’t stay in its laneplus sinus problems, strange rashes, or nerve symptoms
that feel like your body is texting you in Morse codeyour doctor may mention something with a long name and a
longer story: Churg-Strauss syndrome.

Today, most clinicians call it eosinophilic granulomatosis with polyangiitis (EGPA). It’s rare,
often misunderstood, and famously good at disguising itself as “just allergies” until it isn’t. This guide breaks
down the symptoms, what we know about causes, and how doctors put the puzzle
together for diagnosiswithout turning your brain into medical alphabet soup.

Important: This article is for education and can’t diagnose you. If you have concerning symptoms (especially
breathing trouble, chest pain, weakness, numbness, or severe abdominal pain), seek medical care promptly.

What Is Churg-Strauss Syndrome (EGPA)?

Churg-Strauss syndrome (EGPA) is a type of vasculitis, meaning inflammation of blood vessels.
When blood vessels become inflamed, they can narrow and reduce blood flowkind of like a kinked garden hose, but
the “garden” is your organs.

EGPA is strongly linked with asthma and allergic disease, and it involves high
levels of a white blood cell called an eosinophil. Eosinophils are part of the immune system;
they’re useful in the right context, but in EGPA they can build up and cause inflammation in tissues and organs.

EGPA can affect many parts of the body, but the most commonly involved areas include the lungs,
sinuses, skin, nerves, and sometimes the heart,
gastrointestinal tract, and kidneys.

Why the Name Changed (And Why You’ll See Both)

“Churg-Strauss syndrome” is the older name. “Eosinophilic granulomatosis with polyangiitis” is the newer, more
descriptive name. It highlights the key features:

• Eosinophilic: eosinophils are elevated and active in tissues
• Granulomatosis: certain patterns of inflammation can form small clusters (granulomas)
• Polyangiitis: inflammation can involve multiple blood vessels

You may still see “Churg-Strauss” used in older medical records, some patient communities, or even in casual
conversations because, let’s be honest, “EGPA” is easier to say than the full name.

Symptoms of EGPA: What It Looks Like in Real Life

EGPA symptoms can unfold over time. Some people notice years of allergy/asthma issues before anything screams
“vasculitis.” Others have a faster, more dramatic shift. Symptoms also vary depending on which organs are involved.

1) Asthma and allergy symptoms (often the opening act)

Many people with EGPA have adult-onset asthma or asthma that becomes harder to control. Common
ear/nose/throat features include:

• Wheezing, shortness of breath, coughing
• Chronic sinus congestion or sinus infections
• Runny nose, facial pressure or pain
• Nasal polyps (soft growths in the nasal passages)

2) Eosinophilic inflammation (when the immune system overbooks itself)

Elevated eosinophils can inflame tissuesespecially in the lungs and digestive tract. Possible signs include:

• Chest tightness, coughing that lingers, or new/worsening breathing symptoms
• Chest pain or shortness of breath not explained by typical asthma patterns
• Abdominal pain, nausea, diarrhea, or (less commonly) blood in stool
• Unexplained fatigue, feverish feelings, weight loss, or general “I’m not okay” vibes

3) Vasculitis symptoms (the plot twist)

When blood vessel inflammation becomes prominent, symptoms can get more specific and sometimes more serious.
Commonly affected systems include:

A “red flag” combo that raises suspicion

Doctors tend to raise an eyebrow (the diagnostic kind) when they see a pattern like:
asthma + chronic sinus problems (often with polyps) + high eosinophils + new nerve or skin symptoms.
Not everyone has every feature, but this cluster often prompts testing for EGPA.

A quick example (because symptoms are easier with a story)

Imagine a 42-year-old who developed asthma in their late 30s. In the past year, they’ve needed more steroid bursts,
started getting frequent sinus infections, and were told they have nasal polyps. Then, out of nowhere, they develop
tingling and weakness in one foot and a new purplish rash on their legs. A blood test shows high eosinophils.
That combination doesn’t prove EGPAbut it’s enough to make clinicians investigate it seriously.

Causes of EGPA: What We Know (And What We Don’t)

Let’s be upfront: the exact cause of EGPA isn’t known. Most experts consider it an
autoimmune or immune-mediated disease, meaning the immune system mistakenly targets the body’s own
tissues and blood vessels.

Immune system overreaction: the leading theory

EGPA seems to involve two overlapping processes:

• Eosinophilic inflammation (eosinophils infiltrate tissues and drive swelling and damage)
• Vasculitis (immune-driven blood vessel inflammation that can injure organs)

ANCA: present in some, not all

EGPA is often discussed alongside other ANCA-associated vasculitides. ANCA are antibodies that can
be detected in blood tests. Here’s the key point: some people with EGPA have ANCA positivity, and
many do not. In practice, ANCA-positive EGPA can be more strongly associated with certain vasculitis features
(like neuropathy or kidney involvement), while ANCA-negative disease may lean more toward eosinophilic organ
involvement (like the lungs or heart). This is a trendnot a rule carved into stone.

Do medications “cause” EGPA?

You may see discussions about asthma medications and EGPA. The careful, evidence-based way to say it is:
EGPA can be identified after changes in asthma therapyespecially when oral steroids are reduced.
That doesn’t automatically mean a medication caused EGPA; sometimes the underlying disease becomes visible when
steroid masking is removed. If you’re worried about a specific medication, talk with your clinician before making
changesespecially with asthma treatments.

Risk factors (more “associated with” than “guarantees”)

• History of asthma, especially adult-onset or difficult-to-control asthma
• Chronic allergic rhinitis or sinus disease, often with polyps
• Elevated eosinophils at some point in the illness

Diagnosis: How Doctors Confirm EGPA

Diagnosing EGPA is rarely one magic test. It’s more like assembling a playlist where every track is a clue:
symptoms, labs, imaging, and sometimes tissue biopsy.

Step 1: Clinical history and physical exam

Clinicians look for the overall pattern: asthma timeline, sinus symptoms, allergic history, rashes, nerve symptoms,
gastrointestinal complaints, and signs of organ involvement (like heart symptoms or kidney issues).

Step 2: Blood and urine tests

Common tests used to support (or challenge) the diagnosis include:

• Complete blood count (CBC) to check eosinophil levels
• Inflammation markers (such as ESR/CRP)
• ANCA testing (helpful when positive, but a negative result doesn’t rule EGPA out)
• Kidney function tests and urinalysis (to look for kidney involvement)
• Sometimes IgE levels and other immune studies, depending on the case

Step 3: Imaging (lungs and sinuses often star here)

Because the lungs and sinuses are commonly involved, clinicians may use:

• Chest X-ray or CT scan to look for lung changes or infiltrates
• Sinus CT if chronic sinus disease or polyps are suspected

Step 4: Testing organ-specific symptoms

EGPA can affect different organs, so additional tests depend on what’s happening:

• Nerve conduction studies if neuropathy is suspected
• Echocardiogram, cardiac MRI, or other cardiac tests if heart involvement is a concern
• GI evaluation if there’s significant abdominal pain, bleeding, or weight loss

Step 5: Biopsy (often the most convincing evidence)

When feasible, doctors may recommend a biopsy of affected tissue (skin, nerve, lung, or other
organs). Under a microscope, specialists can look for patterns consistent with EGPAsuch as eosinophil-rich
inflammation and signs of vasculitis. Biopsy isn’t always possible, but when it is, it can be a major piece of the
diagnostic puzzle.

What about “criteria”?

You may see references to classification criteria developed by expert groups (for example, ACR/EULAR).
These are designed mainly for research consistency, but they can be useful clinically as a structured way to think
through features like asthma, nasal polyps, eosinophilia, neuropathy, and biopsy findings. Importantly, they are not
a replacement for a clinician’s full evaluationor for ruling out other conditions that can mimic EGPA.

Conditions That Can Mimic EGPA (And Must Be Ruled Out)

Because EGPA overlaps with asthma, allergies, and eosinophilia, doctors often rule out other causes before settling
on EGPA. Examples include:

• Severe asthma with chronic rhinosinusitis (without vasculitis)
• Hypereosinophilic syndromes (eosinophilia-related disease without classic EGPA features)
• Parasitic infections (a common reason eosinophils rise in some settings)
• Drug reactions that cause eosinophilia and systemic symptoms
• Allergic bronchopulmonary aspergillosis (ABPA) in people with asthma and lung findings
• Other forms of vasculitis or autoimmune disease

This “rule-out” step matters because treatment strategies differ, and getting the label right helps protect organs
and avoid unnecessary therapies.

How to Prepare for a Diagnostic Appointment

If EGPA is being considered, you can make the visit more productive by bringing specificsbecause “I felt weird”
is honest, but “I felt weird starting October 12 and my right foot stopped cooperating” is gold.

• Write a timeline of asthma/sinus symptoms, steroid bursts, ER visits, and new symptoms
• List current and past medications (including inhalers, biologics, allergy meds, supplements)
• Bring copies of recent labs, imaging reports, and specialist notes if available
• Note red-flag symptoms: numbness/weakness, chest pain, severe abdominal pain, unexplained rash
• Ask what tests are being ordered and what they’re meant to clarify

What Happens After Diagnosis (A Quick, Helpful Snapshot)

While this article focuses on symptoms, causes, and diagnosis, people naturally ask, “Okay… then what?”
Management is individualized and depends on severity and organ involvement. Many patients require
corticosteroids and sometimes additional immune-targeting therapies. Because EGPA can involve the
lungs, ENT system, nerves, heart, kidneys, and more, care often becomes a team sport involving rheumatology,
pulmonology, ENT, neurology, and sometimes cardiology.

The Bottom Line

Churg-Strauss syndrome (EGPA) is a rare immune-mediated vasculitis that often starts with asthma and sinus disease,
then may progress to eosinophilic inflammation and blood vessel involvement affecting organs like nerves, skin,
lungs, heart, GI tract, and kidneys. Diagnosis is based on the whole patternsymptoms, eosinophil levels, imaging,
targeted organ testing, and sometimes biopsy. If the “asthma + sinus + eosinophils + new systemic symptoms” pattern
shows up, pushing for a thorough evaluation can make a real difference.

Experiences: What EGPA Can Feel Like (Real-World Patterns Patients Describe)

The word “experience” can mean a lot of thingssymptoms, emotions, the diagnostic process, and the weird limbo of
knowing something is wrong but not having a name for it. The stories below are composite experiences
based on common clinical patterns people report (not a single individual’s personal medical story).

1) “My asthma changed its personality”

One of the most common threads is that asthma stops behaving like asthma. People describe needing more rescue
inhaler use, getting frequent steroid bursts, or feeling short of breath even when their usual triggers aren’t
around. Some say, “I’d had allergies for years, but suddenly my lungs were running the show.” In hindsight, the
shift wasn’t just worse asthmait was asthma plus something systemic building underneath.

What can be frustrating is how reasonable the early explanations sound: seasonal allergies, a lingering virus,
stress, “maybe you need a stronger inhaler.” And sometimes those are correct! But when the breathing symptoms are
joined by unexplained fatigue or recurring sinus inflammation that refuses to quit, people often start to wonder
if there’s a bigger pattern.

2) “The sinus saga that never ended”

Chronic sinus symptoms can feel like living with a low-grade head cold that pays rent and never moves out.
People report constant congestion, facial pressure, postnasal drip, and repeated antibiotic courses. When nasal
polyps enter the picture, it can become a long loop of ENT visits, sprays, and temporary relief.

A common emotional beat here is doubt: “Am I just sensitive? Am I being dramatic?” Spoiler: persistent symptoms
deserve attention, especially when combined with asthma and abnormal blood tests. Many people feel validated when a
clinician finally says, “These issues together can point to something like EGPA. Let’s investigate properly.”

3) “The symptom that didn’t match the brochure”

The moment that often pushes the workup forward is a symptom that doesn’t fit the “allergy/asthma” scriptlike a
new rash, severe muscle aches, or nerve symptoms. People describe tingling in the hands or feet, burning pain,
sudden weakness, or a foot that seems to “drop” while walking. That can be scary, because nerve symptoms feel
immediate and personal in a way that congestion doesn’t.

Many patients describe a diagnostic “lightbulb moment” when a doctor connects the dots: asthma history, sinus
disease, high eosinophils, and nerve changes. Even before a diagnosis is confirmed, having a coherent explanation
can feel like finally getting the right map after taking three wrong exits.

4) “The blood test that changed everything”

People often remember the first time someone said, “Your eosinophils are really high.” It can be confusingmost of
us don’t walk around thinking about eosinophils. Some patients describe spiraling into late-night searches (which
is basically the modern version of going into the woods with a candle).

In real life, that lab result is usually just one clue, not a diagnosis by itself. But it often triggers a more
comprehensive workup: imaging, antibody testing, and sometimes biopsy. Patients frequently describe this phase as
a mix of hope (“Maybe we’ll finally know what this is”) and exhaustion (“How many tubes of blood do you need to
solve the mystery?”).

5) “Relief… and then the next set of questions”

Getting an EGPA diagnosis can bring relief because it validates what someone has been feeling. But it also opens a
new chapter: learning what organ involvement means, why multiple specialists may be involved, and what monitoring
looks like over time.

A practical takeaway many patients share: keep a symptom log, ask for copies of key lab trends (especially
eosinophils and inflammatory markers), and don’t be shy about reporting new symptoms. EGPA is the kind of condition
where patterns matter, and you are the world’s best historian of your own body.