About eosinophilic asthma

Eosinophilic asthma

Eosinophilic asthma is a subtype of asthma that is often severe. This subtype is part of type 2 (Th2) asthma and is sometimes also called eos asthma or e-asthma. Adults who develop asthma may have this subtype. It can also occur in children and young adults.


Asthma is a long-term lung disease. It causes episodes of coughing, wheezing, chest tightness, and shortness of breath. Increased mucus in the airways can cause spasms of the bronchial tubes, making it difficult to breathe. Symptoms can be mild or severe, and sometimes life-threatening. Eos asthma may result from an environmental allergy or hypersensitivity, however, many patients who have eos asthma do not have a history of allergic conditions, such as hay fever, food allergy, eczema, or other allergic conditions.

Eosinophils and asthma

Eosinophils are white blood cells that fight certain infections. They also promote inflammation. Increased eosinophils can be seen in a variety of conditions including allergy (food and environmental), parasite infections, and certain cancers, to name a few.

In eos asthma, the numbers of eosinophils are increased in blood, lung tissue, and mucus coughed up from the respiratory tract (known as sputum). The whole respiratory tract is involved in airflow obstruction from the sinuses to the small airways. Patients with eos asthma often suffer from chronic sinus disease and nasal polyposis (growths or polyps in the nose). Research has shown a correlation between too many eosinophils in the blood and the future risk and severity of asthma attacks.

Image of eosinophil cell with drawings of all the parts

Asthma severity

Asthma can range in severity and treatment may vary. To outline the best treatment course, it is important for a health care provider to determine the subtype of asthma. There are new therapies that target specific types of asthma.

Eosinophilic asthma can be severe yet is often manageable with the correct medication and treatment.

Infographic of ways eos asthma affects the body


The cause of eos asthma is not known. Eos asthma is not typically triggered by underlying environmental allergy (e.g., pollen, dust mites, smoke, and pet dander).


The exact prevalence of eos asthma is not known. It is estimated that approximately 10% of all asthma is categorized as severe and that approximately 50% of all asthma is eosinophilic. Eos asthma is most commonly diagnosed in adults 35-50 years old, yet it is sometimes seen in older adults or pediatric patients. Eos asthma affects males and females equally.

Infographic that states: 10% of all asthma is categorized at severe.

Eos asthma brochure thumbnail with arrow prompting 'click to download'
APFED developed a brochure about eosinophilic asthma. We hope it helps you and others learn more about this disease.

Eosinophilic asthma symptoms

People with eos asthma typically have the following symptoms:

  • Wheezing
  • Coughing
  • Shortness of breath/difficulty breathing
  • Chest tightness
  • Lung function abnormalities (airflow obstruction)
  • Chronic rhinosinusitis with nasal polyps
  • Inflamed nasal mucous membrane

Symptoms are often severe and can be persistent.

Young adult woman at the doctors. She's holding her chest with one hand and they are talking about eos asthma diagnosis.

Eosinophilic asthma life expectancy and prognosis

People who have asthma may experience a decline in lung function faster than people who do not have asthma. This is particularly true for people who smoke and those who have asthma that is not well managed.

Death from asthma is rare, especially if a person is receiving proper treatment. Most deaths from asthma are preventable.

Asthma can be debilitating and asthma-related episodes can be frightening. Uncontrolled asthma may interfere with daily activities, such as school and work.

Many patients with eos asthma are able to manage their symptoms with inhaled or oral steroids. However, some patients experience persistent asthma attacks that are relatively resistant to typical treatments. New and emerging biologic treatments that target eosinophils may help these patients control their asthma.

As with other subsets of asthma, patients who have eos asthma should receive ongoing medical care to maintain their health.

Adult man and woman sitting on a park bench. They both have a serious look and are facing the viewer.
Black doctor and elderly man in a medical consultation regarding eos asthma
Young adults that are sports minded sitting in a gym looking serious.
Thin, middle aged woman with short hair coughing into her hand. The doctor is standing behind her holding a stethoscope to the back of her lungs.