Differences Between Asthma and Bronchitis

Asthma and bronchitis both involve inflammation of the lower airways. However, there are important differences in cause, symptoms, diagnosis and treatment.

Asthma and bronchitis are inflammatory lung diseases in which the lower airways swell, resulting in breathing difficulty. Asthma is a chronic disease characterized by recurrent episodes of airway narrowing. Bronchitis can be a short-term or acute illness, typically lasting several weeks, or an ongoing, chronic disease. Bronchitis involves irritation of the mucous membranes lining the airways. Although some similarities exist, asthma and bronchitis are different diseases with different treatment strategies.

Is This an Emergency?

If you are experiencing serious medical symptoms, seek emergency treatment immediately.

Different Disorders

Acute bronchitis is an infection of the airway lining with a cough that typically lasts several weeks. It is usually caused by a viral infection. Less than 10 percent of cases are due to a bacterial infection, according to the American College of Chest Physicians. The lining of the airways returns to normal after the infection clears. Chronic bronchitis is a more serious disease that occurs primarily in people who smoke or have long-term exposure to air pollutants, causing permanent airway damage and breathing difficulties.

Asthma is a chronic disease that causes inflammation and swelling in the airways. People with asthma experience recurrent episodes of airway obstruction, which is characteristically reversible -- either spontaneously or with medication.

Signs and Symptoms

Symptoms of asthma and bronchitis are similar but with distinctions. People with asthma often experience tightness in the chest, shortness of breath and wheezing during an attack. Acute bronchitis typically causes a hacking cough, with or without phlegm production. Chronic bronchitis is associated with a persistent, phlegm-producing cough and wheezing.

These symptoms are also seen with other lung conditions, so they are not specific enough to make a diagnosis. Asthma and chronic bronchitis are both characterized by acute flare-ups when symptoms worsen and can be life-threatening. Seek medical attention if symptoms worsen or are not responding to medication.


Acute bronchitis is generally diagnosed by a sudden onset of a cough that is not caused by a cold, asthma or a more serious respiratory disease, such as pneumonia. The diagnosis is typically based on medical history, symptoms and a physical examination.

Chronic bronchitis is defined as bronchitis with a phlegm-producing cough lasting at least 3 months for 2 consecutive years. In addition to a history and physical, tests used for diagnosis may include a pulmonary function test to assess airflow in the lungs and a chest x-ray.

Asthma is a more complicated diagnosis that requires tests to check for airway obstruction and the capacity to exhale under different test conditions. The tests will be repeated after use of an inhaled medication to open the airways to determine reversibility of the airflow obstruction.


Acute bronchitis usually goes away on its own. Because most cases of acute bronchitis are caused by a viral infection, antibiotics are not necessary or effective. In rare cases, bronchodilators -- inhaled medicines that open the airways -- may be prescribed if wheezing accompanies the cough.

Chronic bronchitis treatment typically includes several strategies, including vaccinations for influenza and pneumonia, use of steroids to reduce inflammation, and treatment with antibiotics -- particularly during flare-ups 3. Other treatments may include the use of bronchodilators to dilate the airways or medications to help clear excess mucus.

Asthma treatment focuses on two strategies. Reducing the frequency and severity of attacks is accomplished by limiting exposure to triggers and using so-called rescue medications to treat sudden symptoms. Controlling the underlying inflammation and constriction of the airways is the other goal of asthma treatment. Inhaled corticosteroids are commonly prescribed for long-term management of inflammation. Leukotriene modifiers (Singulair, Accolate, Zyflo) and theophylline (Theolair, Theo-24) are other long-term control medications.

Reviewed by: Tina M. St. John, M.D.