Asthma is a chronic condition that affects about 1 in 13 U.S. people. It causes a narrowing of your airways that can interfere with breathing.

Currently, research does not support the use of antibiotics for treating asthma except in specific situations, such as when laboratory test results confirm a bacterial infection.

It’s not clear what causes asthma. Some factors that might contribute to its development include:

Researchers are continuing to examine whether antibiotics may help treat asthma symptoms. Keep reading to learn how antibiotics work and what researchers have found so far.

Antibiotics are medications that kill and inhibit the growth of bacteria. The discovery of antibiotics revolutionized modern medicine. In the little over 100 years since antibiotics were first discovered, the human life span has increased by 23 years.

Antibiotics aren’t effective at treating viral, fungal, or parasitic infections. Research suggests bacterial infections play a minor role in flare-ups of asthma, while viral infections play a major role.

Doctors try to avoid prescribing unnecessary antibiotics because they can cause side effects and contribute to antibiotic resistance. Antibiotic resistance is when drugs designed to kill certain strands of bacteria stop being effective.

According to the Centers for Disease Control and Prevention (CDC), antibiotic resistance is one of the most urgent threats to public health. It leads to at least 23,000 deaths per year in the United States.

Short-term worsening of asthma symptoms is referred to as an asthma attack, flare-up, or exacerbation. Theoretically, antibiotics could help kill bacteria that contribute to asthma flare-ups. But bacterial infections seem to make up a small percentage of flare-ups.

The risks of doctors overprescribing antibiotics for asthma may outweigh the benefits in many cases. And researchers haven’t found enough evidence to justify prescribing antibiotics outside of specific situations, such as a confirmed bacterial infection.

In a 2017 study that examined medical files from 100 hospitalized women, researchers found that respiratory infections caused almost three-quarters of asthma flare-ups.

Antibiotics were prescribed to about half of these women, but only 7% of them tested positive for bacterial infections. Women prescribed antibiotics stayed in the hospital an average of 2.35 days longer, but both groups of women had good outcomes.

Likewise, in a large 2020 study with 110,418 participants, researchers found that people with acute lower respiratory tract infections were overtreated with antibiotics.

In a 2018 review of six studies, researchers investigated whether antibiotics were safe and helpful for people having asthma flare-ups. They concluded the results of their study backed the position of the British Thoracic Society guidelines that doctors should not routinely prescribe antibiotics for asthma.

Researchers found a limited amount of evidence that antibiotics given in the time of a flare-up may lead to more symptom-free days, but findings were inconsistent across studies. Researchers had low confidence in the results.

When are antibiotics recommended?

Antibiotics may help asthma symptoms in people with a confirmed bacterial respiratory infection. Types of bacteria linked to asthma flare-ups include:

  • Mycoplasma pneumoniae
  • Haemophilus influenzae
  • Streptococcus pneumoniae
  • Chlamydia pneumoniae
  • Moraxella catarrhalis

The antibiotic azithromycin is sometimes included as a treatment option for severe asthma that doesn’t respond to other treatments in the guidelines of the:

  • Global Initiative for Asthma
  • European Respiratory Society/American Thoracic Society
  • British Thoracic Society

In a 2021 study, researchers found evidence that antibiotics may improve symptoms in people with difficult-to-treat asthma. Of the 101 people in the study with asthma, 61.4% also had chronic obstructive pulmonary disease (COPD), and 77% said their symptoms began after a respiratory illness.

Exposure to antibiotics early in life, especially antibiotics to treat respiratory infections, may lead to an increased risk of asthma later in life. Research suggests the association is strongest in younger children and females.

In a 2022 rodent study, researchers found evidence that early exposure to antibiotics may cause asthma and allergies by killing healthy bacteria in the digestive tract.

Four primary types of medications are used to treat asthma. They include:

  • Quick-relief medications: Quick-relief medications are usually administered through an inhaler and only used to treat asthma attacks. They include short-acting, rapid-onset beta2-agonists and anticholinergic bronchodilators.
  • Controller medications: These medications are used to correct long-term swelling and excess mucus in your airways. They include anti-inflammatories, anticholinergics, and long-acting bronchodilators.
  • Combination of quick-relief and controller medications: These medications provide short- and long-term relief of asthma symptoms. However, they haven’t yet been approved by the Food and Drug Administration (FDA) for this purpose.
  • Biologics: Doctors may prescribe biologics when other treatments aren’t working or to control a particular trigger. These medications reduce inflammation by targeting proteins made in your immune system called antibodies.

Avoiding asthma triggers may also help you manage symptoms. Common triggers include:

  • stress
  • intense exercise (but it’s not recommended to avoid exercise altogether)
  • temperature extremes
  • some medications, such as aspirin
  • smoke, pollution, fumes, and other irritants in the air
  • allergens, such as pollen, dust mites, or animal dander

Most medical guidelines don’t recommend antibiotics for treating asthma except when asthma doesn’t respond to other treatments or lab test results confirm a bacterial infection.

Respiratory infections are a common trigger for asthma flare-ups, but viruses seem to cause most infections. Unnecessary use of antibiotics can contribute to antibiotic resistance and cause side effects.