Eosinophilic asthma is a type of asthma that is associated with high levels of white blood cells called eosinophils.
In the United States (U.S.), an estimated 25.7 million people have some form of asthma, and 15 percent of these people have severe asthma that is difficult to control with standard medications.
Eosinophilic asthma is considered a leading cause of severe asthma, affecting 50 to 60 percent of people with the severe form of the disease.
In the population as a whole, eosinophilic asthma is rare, affecting only 5 percent of adults with asthma.
Eosinophilic asthma is like other forms of asthma in that people with the condition suffer from inflamed airways, blocked by fluid and mucus and experience spasms that make it difficult to breathe.
Unlike other kinds of asthma, however, eosinophilic asthma involves abnormally high levels of a particular type of white blood cell called eosinophils.
Eosinophils are part of the immune system and help the body fight off infection. However, high levels of eosinophils can cause inflammation in the airways, affecting the sinuses and nasal passages as well as the lower airways.
In general, as the level of eosinophils increases, inflammation and other symptoms of asthma become more severe.
This form of asthma most often develops in people between the ages of 25 and 35. People with eosinophilic asthma usually do not suffer from allergies. This condition can be difficult to treat and may have a detrimental effect on an individual’s quality of life.
A specific cause for eosinophilic asthma has not been identified. While other forms of asthma are triggered by allergic responses to environmental factors, such as pollen or pet hair, eosinophilic asthma does not develop in this way.
High levels of eosinophils can develop when the body is fighting off a parasitic infection, but scientists have not yet determined what causes these levels to spike in cases of eosinophilic asthma.
Asthma can run in families, so researchers are exploring the possibility of a genetic connection. However, no direct genetic link has been found with eosinophilic asthma.
The symptoms of eosinophilic asthma include:
- shortness of breath
- wheezing
- tightness in the chest
- coughing
- obstructed airflow
- stuffy nose
- nasal drainage
- chronic sinus infections
- anosmia, or a lost sense of smell
- nasal polyps
Individuals should see a doctor if they frequently experience:
- shortness of breath
- coughing
- wheezing
- tightness in the chest
Prompt and consistent treatment of eosinophilic asthma is important, as inflammation of the airways can lead to permanent damage, such as a thickening of the airway walls or scarring of the lung tissue.
People with asthma are encouraged to see a doctor at least once a year to make sure their treatment plan is effective. Symptoms that require prompt medical attention include:
- dizziness or feeling faint
- wheezing while breathing
- difficulty doing routine activities
A person should seek emergency care if any of these symptoms develop:
- quick-acting medication provides no relief after 15 minutes
- difficulty speaking or walking at a normal pace
- lips or nails turning blue
- taking more than 30 breaths a minute
- breathing causes nostrils to flare and the throat and ribs to feel stretched
The first step in diagnosing eosinophilic asthma is diagnosing severe asthma. The next steps involve evaluating:
- shortness of breath with exercise
- airways that stay blocked
- limited airflow
- chronic sinus disease
- nasal polyps
- response to systemic steroid medications, such as oral corticosteroids
However, the definitive factor in diagnosing eosinophilic asthma is finding high levels of eosinophils. A doctor can measure these levels by analyzing a person’s blood, sputum, or saliva, or by conducting a bronchial biopsy.
Researchers have noted that the symptoms of eosinophilic asthma differ from classic asthma and, in fact, more closely resemble those of chronic pulmonary obstructive disorder (COPD).
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Each one of these conditions, including eosinophilic asthma, requires a specific form of treatment.
Until recently, oral corticosteroids were the standard treatment for eosinophilic asthma. Although many people respond well to these medications, they are not always successful at controlling this disease. Some people also became dependent on this medication.
New treatments called biologic therapies are now being used to treat this condition. Medications known as leukotriene antagonists may also be used to reduce inflammation.
In addition to these asthma medications, antibiotics may be used to treat the sinus infections that frequently accompany this form of asthma.
People with eosinophilic asthma may also experience:
- chronic sinus infections
- nasal polyps
- eosinophilic otitis media, an inner ear infection
- aspirin-exacerbated respiratory disease
In addition, this condition is also linked to other conditions characterized by high levels of eosinophils. Although eosinophil-associated diseases are uncommon, they are a growing problem around the world, especially when they attack the gastrointestinal system.
Although the connection between eosinophils and asthma has been known since 1889, researchers are continuing to investigate the best way to treat eosinophilic asthma.
The ongoing development of new treatments has significantly improved the outlook for people with this condition.
People with this condition tend to have frequent flare-ups and can become heavily dependent on oral corticosteroids, which have serious side effects. The disease can even be fatal.
Thanks to new treatment options, this does not have to be the case. However, people with eosinophilic asthma must stick to their treatment plan and practice self-care to keep themselves in the best health possible.