5 Characteristics of Eosinophilic Asthma
A big breakthrough in treating asthma came with the realization that asthma is not just one general disease. Instead, there are several different subtypes that fall under the umbrella of asthma. Eosinophilic asthma is one of these subtypes.
Eosinophilic asthma is associated with an abnormally high level of eosinophils, a type of white blood cell. Eosinophils play a role in how your immune system works. They help protect your body against harmful things like bacteria or parasites by releasing chemicals that cause inflammation. But when eosinophils come into contact with cells in your airways, they can cause inflammation that triggers asthma.
As with other types of asthma, people with eosinophilic asthma will experience symptoms like wheezing, coughing, chest tightness and shortness of breath. But there are a few additional symptoms that are often seen with eosinophilic asthma, and if you experience them, it may prompt your doctor to do some further testing.
Inhaled corticosteroids are commonly used in the treatment of asthma. They act as an anti-inflammatory and help decrease swelling in the airways, making it easier to breathe. Many people are able to keep their asthma under control with proper use of inhaled steroids.
But people with eosinophilic asthma often have what is known as severe asthma. This means that even with high doses of inhaled corticosteroids, they are unable to adequately control their asthma. They may have symptoms of asthma the majority of the time and are more likely to have frequent, severe asthma attacks that land them in the emergency room.
Asthma commonly develops during childhood, but eosinophilic asthma often starts later, particularly from ages 35-50 (though it may sometimes be seen in children). It may be referred to as late-onset or adult-onset asthma.
Eosinophilic asthma causes swelling along the entire respiratory tract from the sinuses to the lower airways, obstructing airflow and increasing mucus production. This can lead to chronic sinus and ear infections. Patients may report stuffy or runny nose, drainage from the ears, and decreased sense of smell and hearing. Nasal polyps, which are small, painless tear-drop shaped skin growths, are often present.
Many people with asthma also have underlying allergies, such as dust or animal dander. Exposure to the allergen can start an inflammatory response in the body, leading to an asthma attack. However, people with eosinophilic asthma generally don’t have a history of allergies.
When eosinophilic asthma remains untreated, irreversible changes in the structure of your airways can occur, causing chronic airway obstruction. Patients may experience difficulty breathing with physical activity, and lung function tests in the doctor’s office can show decreased flow of air through the lungs. There may be similarities with another lung disease, chronic obstructive pulmonary disorder (COPD), and eosinophilic asthma may even be mistaken for COPD at times.
If your doctor suspects you may have eosinophilic asthma, a definitive diagnosis can be made by testing your sputum, the phlegm you cough up, to see if a large number of eosinophils are present. Sometimes your blood or a small amount of tissue from your lungs can be tested too. Since eosinophilic asthma is often severe, a proper diagnosis is important to ensure you get the right treatment.
In the past, treatment for eosinophilic asthma was limited. If traditional asthma treatments like inhaled steroid and fast-acting bronchodilators didn’t work, patients could be treated with oral steroids, which work systemically throughout the body. Oral steroids are often effective, but due to their side effects, they aren’t recommended to be used long term.
Now, however, new treatments known as biologics are available. They work to decrease the number of circulating eosinophils, thereby reducing exacerbations of asthma. Examples include benralizumab (Fasenra), mepolizumab (Nucala), and reslizumab (Cinqair). Clinical trials have shown significant promise for patients with severe eosinophilic asthma that was resistant to other treatments. Other biologics are currently being studied and are expected to be released in the future.
Living with eosinophilic asthma can be challenging, but with advancing knowledge and treatments, the outlook for the future is improving. Talk to your doctor if you’d like to learn more about eosinophilic asthma or treatments that are available to you.