What Is Eosinophilic Bronchitis?

Table of Contents
View All
Table of Contents

Eosinophilic bronchitis is a common cause of chronic (long-term) cough. The condition is characterized by inflammation of the airways, which is common in bronchitis. However, with eosinophilic bronchitis, there is no bronchospasm (narrowing of the airways). There are, however, increased eosinophils (white blood cells that are associated with allergic disease, but also fight parasitic infections) in the lungs. 

Eosinophilic bronchitis is not well understood, and it’s thought to be underdiagnosed. It has been linked to exposure to occupational toxins, including dust. Eosinophilic bronchitis can be treated using steroids, which are highly effective at reducing the cough caused by the condition. Healthcare providers will usually rule out other lung conditions like bronchitis, pneumonia, or chronic obstructive pulmonary disease (COPD) before diagnosing eosinophilic bronchitis. 

 Here’s what you should know about eosinophilic bronchitis.

person coughing

Daniel Allan / Getty Images

Definition

Eosinophilic bronchitis is a type of chronic cough.

What Is Considered Chronic Cough?

In adults, chronic cough is one that lasts for eight weeks or more; in kids, it's one that lasts for at least four weeks.

Like other forms of bronchitis, eosinophilic bronchitis is characterized by an inflammation of the bronchi—the tubes that carry air to the lungs. Unlike with other forms of bronchitis, people with eosinophilic bronchitis don’t experience the narrowing of the airways, known as bronchospasm.

The lack of this airway sensitivity is what sets eosinophilic bronchitis apart from cough-variant asthma. This is why eosinophilic bronchitis is sometimes called non-asthmatic eosinophilic bronchitis. 

People with eosinophilic bronchitis have a higher than normal amount of eosinophils—a type of white blood cell—in their sputum (phlegm), which is the mucus secreted by the bronchi. This can be useful in diagnosing the condition. 

Medical professionals are still learning about eosinophilic bronchitis, and it’s believed that the condition is underdiagnosed. There’s limited research on how long the condition lasts.

In some people, it resolves without treatment, but in others, it recurs even with treatment.

Eosinophilic Bronchitis and Asthma: What's the Connection?

There’s some indication that eosinophilic bronchitis is a precursor to asthma, so if you experience persistent, unexplained coughing, it’s important to talk with your healthcare provider about whether you might have eosinophilic bronchitis.

Symptoms

The primary symptom of eosinophilic bronchitis is a chronic, persistent cough that lasts for eight weeks or more in adults and four weeks or more in children. Unlike people with asthma, people with eosinophilic bronchitis don’t experience any restriction to their airflow; therefore, shortness of breath is not a symptom of eosinophilic bronchitis.

 The symptoms of eosinophilic bronchitis include:

  • Cough, lasting for a long time
  • Increased cough reflex
  • Sputum eosinophilia, or increased white blood cells in the mucus of the lungs

The symptoms of eosinophilic bronchitis do not include:

  • Shortness of breath or feeling of restricted airways
  • Increased response to allergens or triggers that restrict the airways
  • Mast cells within the airways

Shortness of Breath Is Not a Symptom of Eosinophilic Bronchitis

Overall, the symptoms of eosinophilic bronchitis are similar to cough-variant asthma, with a critical difference: People with eosinophilic bronchitis do not experience restriction to their airways that can cause shortness of breath. 

Causes

Doctors are not sure what causes eosinophilic bronchitis. However, they believe that environmental triggers may play a role in the development of eosinophilic bronchitis. People who are regularly exposed to dust through their work have an increased risk of the condition, it appears. 

Exposure to the following environmental triggers has been shown to increase the risk of eosinophilic bronchitis:

  • Dust
  • Resin hardener
  • Welding fumes
  • Formaldehyde


If you experience chronic cough and have been exposed to any of these triggers, be sure to let your doctor know, as that might speed along diagnosis. 

Diagnosis

The first step toward diagnosing eosinophilic bronchitis is ruling out other conditions like more typical bronchitis, pneumonia, or COPD. Your doctor will do this by listening to your lungs and using imaging such as a chest X-ray or MRI, if necessary.  

Once your doctor has ruled out other conditions, they will likely want to measure the inflammation in your lungs and look for increased eosinophils in the lungs, a hallmark of eosinophilic bronchitis.

This is done using a process called sputum induction. This is a noninvasive procedure that involves breathing in saline solution through an ultrasonic nebulizer. This helps your body bring up more mucus with a cough, allowing the doctor to analyze your sputum. 

In some cases, a doctor may also want to measure nitric oxide levels in your breath. This is used as an indicator of inflammation in the lungs. 

If neither of those procedures yields a clear answer, your doctor may recommend a bronchial lavage. This procedure involves putting a tube into the lungs to gather a sample of fluid from the bronchi. 

Treatment

Eosinophilic bronchitis is treated using inhaled corticosteroids. This treatment—usually delivered using an inhaler and sometimes with a nebulizer—is the same treatment used for asthma. 

There’s no established protocol on which steroids are best for treating eosinophilic bronchitis or for how long they should be administered. Your healthcare provider will discuss a treatment plan that is best for your specific circumstances. 

Most people have their eosinophil levels return toward normal within four weeks of treatment with inhaled steroids. In rare cases, doctors will also prescribe oral steroids to help reduce lung inflammation. 

Avoiding Environmental Triggers

People who have been diagnosed with eosinophilic bronchitis should avoid exposure to dust or other toxins that may have contributed to the development of their condition. 

Coping

There's limited data on the long-term prognosis of eosinophilic bronchitis. A small, early research study indicated that most people recovered fully, but a more recent and larger study suggests that eosinophilic bronchitis is a condition that must be managed over a lifetime. That study found that 66% of people had ongoing inflammation in their lungs. About 9% of people went on to develop asthma. 

If you are diagnosed with eosinophilic bronchitis, you should speak with your doctor about your prognosis. You might have to stay on inhaled steroids long-term in order to keep your cough at bay. In addition, you should take steps to limit your exposure to airborne toxins that could trigger your condition. 

Although a chronic cough can be uncomfortable and annoying, eosinophilic bronchitis is not a dangerous condition. It does not interfere with a person's ability to breathe, and it is highly responsive to treatment. Because of that, the impact on your life should be minimal. 

Summary

Eosinophilic bronchitis is a common cause of chronic cough. It is not well understood, and it’s thought to be underdiagnosed. If you are experiencing a chronic cough, speak with a healthcare provider to determine if you have eosinophilic bronchitis.

A Word From Verywell

Being diagnosed with a condition that you’ve never heard of can be scary, but in this case, there is good news: Eosinophilic bronchitis is a highly treatable condition with a great prognosis. 

Understanding of and treatment for eosinophilic bronchitis is still evolving. Your doctor will be able to guide you toward a treatment path that is effective for you.

Was this page helpful?
Article Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Yıldız, Tekin and Dülger, Seyhan. Non-astmatic eosinophilic bronchitis. Turkish Thoracic Journal. January 2018. doi:10.5152/TurkThoracJ.2017.17017

  2. Lai K, Chen R, Peng W, Zhan W. Non-asthmatic eosinophilic bronchitis and its relationship with asthmaPulmonary Pharmacology & Therapeutics. 2017;47:66-71. doi:10.1016/j.pupt.2017.07.002