Asthma is a complex condition believed to be caused by a combination of genetic and environmental factors. More than 100 gene candidates have been associated with asthma, and there are many environmental risk factors that have been connected to asthma development in children. With such a complex causal profile, asthma prevention is challenging if not impossible. Instead, asthma prevention focuses on preventing exacerbation of the condition.

Avoiding Triggers and Allergens

Most of the time, asthma attacks are caused by inhaling an allergen that triggers airway inflammation, bronchoconstriction, and wheezing. Therefore, the best thing you can do to prevent asthma attacks is to identify and avoid these triggers as best you can.

View common asthma triggers.

Air-filtration System

Air filters can help rid your home of common asthma triggers, including most mold, pollen, dust mites, and other allergens. The best systems, which use high-efficiency particulate air (HEPA) filters, can clear the air of up to 99.9% of pollutants. Air filtration is recommended to control asthma triggers, but experts contend that filtration should not be used as a solution to asthma problems.


These devices increase moisture level in the air by producing water vapor. If cleaned and maintained properly, humidifiers can help ease asthma symptoms.


Immunotherapy injections (allergy shots) are designed to enhance or suppress the immune system. If asthma triggers are unavoidable, immunotherapy is an option for managing asthma symptoms. The goal is to reduce sensitivity to allergens over time. For the first few months, injections are usually administered once a week. After which they might be given once a month for several years until desired results are achieved.

Using Preventative Medication

Recognizing the onset of asthma attacks and treating them immediately is important in preventing severe symptoms. An effective way to do this is with medication. Most asthma medications are used on a regular basis to prevent attacks and are taken via an inhaler, although some may be administered orally or by injection. Some of the more common preventative medications include:

Inhaled corticosteroids

These act like natural body hormones and block inflammation. While steroids are the strongest medicine for asthma, they may have side effects that the other medications lack.

Leukotriene modifiers

They work by counteracting leukotrienes, which are substances released by white blood cells in the lung that cause the air passages to constrict.

Beta Agonists

They are excellent for preventing attacks from being triggered by exercise.

View more asthma medication options.

Testing Lung Function

It's essential to monitor how well your asthma medications are working by testing your lung function regularly. You can use a peak flow meter to measure the amount of air flowing out of your lungs; this self-administered test can reveal narrowing of the airways before the onset of symptoms.

By using a peak flow meter to first establish some baseline measurements and then regularly checking your peak flow rate, you can determine what triggers an asthma attack, when to stop or add medication, and, in worst-case scenarios, when to seek emergency medical care.

View more information about asthma tests.

Asthma Action Plan

Asthma experts, including those at the National Institutes of Health (NIH) and the Centers for Disease Control and Prevention (CDC), recommend developing an asthma action plan with your doctor to help control your asthma. The plan will document important information such as your daily medications (what kind and when you should take them), how to handle asthma attacks, and how to control your asthma symptoms long term.

Asthma Zones

Most plans, including the one recommended by the National Heart, Lung, and Blood Institute (part of the NIH), include three asthma zones—color coded according to severity—to help those with asthma monitor the severity of their symptoms.

Green Zone – “Doing Well”

  • No asthma symptoms during the day or night
  • Able to perform casual activities

Yellow Zone – “Asthma is Getting Worse”

  • Showing symptoms such as coughing, wheezing, or shortness of breath, or
  • Waking at night due to asthma symptoms, or
  • Able to perform some but not all normal activities

Red Zone – “Medical Alert!”

  • Extremely short of breath
  • Quick-relief medications are not helping
  • Unable to perform normal activities
  • Yellow Zone symptoms same or worse for 24 hours

Learn more about Asthma: