How Do I Know if I Have Eosinophilic Asthma?

Medically Reviewed by Carol DerSarkissian, MD on March 10, 2024
4 min read

It’s important to know if you have eosinophilic asthma because it affects the kind of treatment you’ll need. But it’s not always easy to figure out, and your doctor will have to put together different types of information to know for sure. You’ll likely talk about your symptoms and health history, get a physical exam, and get a test that measures your level of eosinophils (the white blood cells that cause swelling in this type of asthma).

To get the most from your appointment, it helps to know what to expect and how you can prepare.

There are three main types of doctors you might see:

  • An allergist, who treats asthma and allergies
  • An immunologist, who treats problems with the immune system, including allergies
  • A pulmonologist, who treats lung diseases

Pulmonologists often treat eosinophilic asthma because it’s often not related to allergies. But it’s helpful to know if you do have allergies and how they could affect treatment, so an allergist or immunologist might still have a role to play.

Your doctor will probably start by asking you questions such as:

  • What are your symptoms? How long have you had them, and how bad do they get?
  • Does anything seem to trigger your symptoms?
  • Have you ever had an asthma attack after taking pain relievers like aspirin, ibuprofen, or naproxen?
  • Does anyone else in your family have asthma?
  • Do you have any allergies?
  • Have you tried an inhaler? Did it help?
  • Are you often short of breath? Is it worse when you exercise?
  • Do you smoke?
  • Have you ever had a job where you might have breathed in harmful chemicals?
  • Have you found anything that helps your symptoms?

After reviewing your symptoms, your doctor may do a physical exam to check your breathing and look for conditions common in people with eosinophilic asthma, including:

  • Swelling in the nose and sinuses
  • Growths in the nose and sinuses, called nasal polyps
  • Middle ear infections

Next, your doctor may measure your level of eosinophils. This is a big piece of the puzzle to figure out if you have eosinophilic asthma. There are three main tests you can get, and each has its tradeoffs.

  • Sputum induction test. For this one, you cough up a mucus sample that your doctor sends off for testing. It has several advantages. For one, you can give the sample right in your doctor’s office. It’s also been used in a lot of research and has shown to be accurate to confirm that you have eosinophilic asthma. The downside is that it can take a while to get the results, and not all labs can do it.
  • Blood test. For this test, your doctor takes a blood sample to measure eosinophils in your blood. The advantages are that pretty much any lab can do it and it’s a lower-cost option. The downside is that the level of eosinophils in your blood isn’t going to tell you for sure that you have eosinophilic asthma. It’s useful, but it's not as telling as the sputum induction test.
  • Bronchial biopsy. This test is much more involved than the others. You’ll be asleep as your doctor places a tube called a bronchoscope into your nose or throat, then threads it into your lungs to collect a tissue sample or some fluid. It’s very accurate, but it's not nearly as easy as the other two.

Breath test. This measures the fractional exhaled nitric oxide (FeNO) in your breath. Higher levels are linked to more eosinophilic inflammation.

To get ready for your doctor’s appointment, it might help to keep a journal of all your symptoms, even ones that don’t seem related to asthma. You can write down:

  • Symptoms and how severe they are
  • Date and time you got the symptoms
  • Anything that might have triggered your symptoms

This will save you from having to recall everything on the spot at your doctor’s office. It also makes sure you don’t forget any important details.

You’ll also want to make a list of any other health conditions you have, as well as any medicines, herbs, vitamins, or supplements you take regularly.

Finally, you might want to write down some questions to ask your doctor, such as:

  • What tests will I need?
  • How accurate are those tests?
  • How will you tell for sure if I have eosinophilic asthma?
  • What can I do to avoid asthma attacks?
  • How will you manage my asthma?
  • How do I use the medicine you gave me?
  • How often will I need to see you?
  • Could anything else be causing my symptoms?
  • Will I need to see other types of doctors as well?
  • Where can I look for more information to learn more?

Sometimes, people with eosinophilic asthma are told they have a different disease, called chronic obstructive pulmonary disease (COPD), which is common in people who smoke. If you’re told you have COPD, ask how you can know it’s COPD and not asthma.