A brief introduction to Eosinophilic Asthma and Non-Eosinophilic Asthma to help you better understand what type of asthma you have and how best to treat each type.
Asthma is a chronic lung disease. It manifests as the inability to breathe. You wheeze when you encounter different triggers. Historically, doctors thought there was one type of asthma. Therefore, all asthma treatment was essentially the same.
Scientists and Doctors now agree on two main types of asthma: Eosinophilic (EA) and Non Eosinophilic Asthma (NEA). (Pronounced ee-oh-sin-a-Phil-ick.)
Each of them have similar symptoms that people with asthma are familiar with, those being wheezing, coughing, shortness of breath, etc. The interesting part is HOW those symptoms manifest in the body. In other words, the root cause of why you have asthma. EA and NEA both start not in the lungs like previously thought, but in the immune system.
Understanding the type of asthma you have can help you and your doctor understand what type of medicine would work best for you, giving you greater control over your asthma.
What is Asthma?
Let’s get some basic definitions so we can better understand this new way of classifying asthma.
First, asthma is a long term and chronic disease of the lungs that makes it difficult, if not impossible, to breathe. Medications, diet, and lifestyle changes help you to manage your asthma. Medications can not cure asthma.
Common symptoms of asthma are: Coughing, wheezing, shortness of breath, and feeling tightness in your chest. If you feel like you can’t breathe, you probably can’t.
Previously, understanding what caused asthma was a bit of a mystery. Genetics, indoor or outdoor allergies, stress, and heck, even the weather are all things that can cause asthma attacks. But no one was really sure why some people were affected by these things and other people weren’t, let alone how to treat beyond a few medications.
In non-asthmatics, when they encounter foreign pathogens like a virus (bad) or cat hair (not as dangerous) the body responds by inflammation to help get rid of the pathogen. The body swells, gets rid of it, and then goes back to a state of “normal”.
In asthmatics, our bodies work a little different. There is no easy return to a state of normal.
For example, people with asthma have persistent and non-resolving inflammation. This means asthmatics bodies swell up from the pathogen (virus or cat hair) and then don’t easily un-swell.
Researchers have discovered the role immune cells play in the different types of asthma inflammation.
These two main types are Eosinophilic Asthma and Non-Eosinophilic Asthma.
What is Eosinophilic Asthma?
Eosinophilic Asthma is the type of asthma that is a result of high eosinophils in the body that cause inflammation and mucus build up. This results in asthma attacks.
Eosinophils are a type of white blood cell that everyone has in their body.
The immune system has several different types of white blood cells that work against foreign pathogens. Like I said above, these pathogens can be anything from a virus, to pollen, to smoke, to cat hair.
Eosinophils live in the entirety of the body as part of our immune system. Anytime you need white blood cells to attack a virus or foreign particle, the body sends eosinophils to save you from the attacker.
For example, a person with EA breathes in a foreign invader into the body (like the cat hair). Their immune system responds by sending not just a small amount of eosinophils, but rather, a HUGE amount of eosinophils!
These massive amounts of eosinophils act like a clog in the pipe in that the inflammation becomes so severe that the body really can’t reduce the inflammation. Which causes more inflammation and the cycle repeats itself.
By this time, the asthmatic has realized something has gone wrong, and usually takes their rescuer inhaler to solve the issue. Until the next time.
Researchers now think that EA is a very common form of asthma with it affecting somewhere between 50-80% of all asthmatics.
Symptoms of Eosinophilic Asthma
A person who has EA typically has more severe asthma symptoms of coughing, wheezing, shortness of breath, and tightness in the chest. If you have attacks that land you in the hospital, it is possible that this is a symptom of EA.
Other symptoms of EA are obstructed airflow due to inflammation and mucus. Think things like a stuffy nose and nasal drainage. Chronic sinus infections and nasal polyps are also symptoms.
How to Know if You Have Eosinophilic Asthma?
The only way to know for sure if you have EA is to go to your doctor and get tested.
Currently, there are 3 methods for determining if you have EA: A blood test, a sputum test, and a test that measures the nitric oxide in your exhales. Your doctor will decide which test to use.
The blood test for eosinophils determines if you have eosinophilc asthma. Over 2% is indicitive of high eosinophils in the body.
Obviously, I’m not a doctor so as always make sure you talkwith your doctor.
How to Treat Eosinophilic Asthma
Treatments for EA include three different preventatives and one for acute attacks.
Corticosteroids - These can be oral or inhaled. They help to control the amount of inflammation in the lungs and the body as a whole. (Examples include Advair, QVAR, and Prednisone.)
Leukotriene Modifiers - This is usually an oral pill. These also help to control the inflammatory response in the body. (Examples include Singular and Zyflo.)
Biological Therapies - These are the latest treatments available for asthma. They vary from injected medicines to IV infusions. This therapy blocks the chemicals in the body that cause inflammation. (Examples include Nucala, Xolair, and Fasenra.)
Rescue Inhalers - These are your inhalers that you take when you have an acute attack. Rescue inhalers are short-acting which means they only have a lasting power of about 4-6 hours. (Examples include Ventolin and Albuterol.)
Non Eosinophilic Asthma
Other factors in the body cause non-eosinophilic asthma. This asthma is usually non-inflammatory and responds to different treatment than EA. Non-eosinophilic asthma will cause asthma attacks just like EA.
It is not based on eosinophils and is based instead on other white blood cells. These other cells are neutrophils. You can also experience NEA with a combination of eosinophils and neutrophils. Finally, you can experience NEA of the paucigranulocytic (non-inflammatory) type.
Unfortunately, less research has been done about this type of asthma. It isn’t as well known because it isn’t as prevalent in the asthmatic population. Non-eosinophilic asthma affects between 10-20% of all asthmatics.
Symptoms of Non Eosinophilic Asthma
Asthmatics who have NEA share the same outward symptoms of coughing, wheezing, shortness of breath, etc.
Internally, symptoms of NEA include a normal or even low amount of eosinophils in their blood combined with higher counts of other immune cells.
Another symptom of NEA is a lack of response to traditional asthma medications like corticosteroids. If you are taking steroids and still find yourself using your rescue inhaler more than 2 days of the week, it might be a good idea to bring up NEA with your doctor.
These asthmatics traditionally have a less severe form of asthma. However, since this asthma type doesn't respond to traditional treatment, it can be more uncontrolled.
How to Know If You Have Non-Eosinophilic Asthma
The only way to know if you have NEA is to get blood work done by your doctor to check the levels of different white blood cells in your body.
If you have been on asthma treatment for a few years and have not responded to it, you can ask about being tested for NEA.
Treatments for Non Eosinophilic Asthma
As steroids do not work for NEA, the treatment options for NEA are different from the traditional asthma medications.
NEA is currently being tested with long acting bronchodialators to see if they work. So far, results are promising. Other treatments are under development including more long acting bronchodilators, certain kinds of antibiotics, and statins.
Wrapping It All Up
There is no cure for asthma. Yet, I am hopeful that further research into cellular and molecular biology will help us gain insights and a way to better treatment options.
If you need to change your medicaitons to better manage your asthma, make an appointment to talk with your doctor.
American Lung Association www.lung.org
Center of Excellence in Severe Asthma www.severeasthma.org.au
“Eosinophilic and Noneosinophilic Asthma” from the ATS Journals https://www.atsjournals.org/doi/full/10.1164/rccm.201611-2232