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"You Can Control Your Asthma” full-color brochure, suitable for downloading and printing [PDF, 4074KB]

What Is Asthma?

Asthma is a disease that affects your lungs. It is the most common long-term disease of children, but adults have asthma, too. Asthma causes repeated episodes of wheezing, breathlessness, chest tightness, and nighttime or early morning coughing. If you have asthma, you have it all the time, but you will have asthma attacks only when something bothers your lungs.

We know that if someone in your family has asthma, you are also more likely to have it. In most cases, we don’t know what causes asthma, and we don’t know how to cure it. You can control your asthma by knowing the warning signs of an attack, staying away from things that trigger an attack, and following the advice of your health-care provider. When you control your asthma, you won’t have symptoms like wheezing or coughing, you’ll sleep better, you won’t miss work or school, you can take part in all physical activities, and you won’t have to go to the hospital

How Is Asthma Diagnosed?

Asthma can be hard to diagnose, especially in children under 5 years of age. Regular physical checkups that include checking your lung function and checking for allergies can help your health-care provider make the right diagnosis.

During a checkup, the health-care provider will ask you questions about whether you cough a lot, especially at night, and whether your breathing problems are worse after physical activity or during a particular time of year. Health-care providers will also ask about other symptoms such as chest tightness, wheezing, and colds that last more than 10 days. They will ask you whether your family members have or have had asthma, allergies, or other breathing problems, and they will ask you questions about your home. The health care provider will also ask you about missing school or work and about any trouble you may have doing certain activities.

A lung function test, called spirometry (spy-rom-e-tree), is another way to diagnose asthma. A spirometer (spy-rom- e-ter) measures the largest amount of air you can exhale, or breathe out, after taking a very deep breath. The spirometer can measure airflow before and after you use asthma medicine.

What Is An Asthma Attack?

An asthma attack happens in your body’s airways, which are the paths that carry air to your lungs. As the air moves through your lungs, the airways become smaller, like the branches of a tree are smaller than the tree trunk. During an asthma attack, the sides of the airways in your lungs swell, and the airways shrink. Less air gets in and out of your lungs, and mucus that your body produces clogs up the airways even more. The attack may include coughing, chest tightness, wheezing, and trouble breathing. Some people call an asthma attack an “episode.”

What Causes An Asthma Attack?

An asthma attack can occur when you are exposed to things in the environment such as house dust mites and tobacco smoke. These are called asthma triggers. Some of the most important triggers are listed below.

How Is Asthma Treated?

You can control your asthma and avoid an attack by taking your medicine exactly as your health-care provider tells you to do and by avoiding things that can cause an attack.

Everyone with asthma does not take the same medicine. Some medicines can be inhaled, or breathed in, and some can be taken as a pill. Asthma medicines come in two types—quick-relief and long-term control. Quick-relief medicines control the symptoms of an asthma attack. If you need to use your quick-relief medicines more and more, you should visit your health-care provider to see if you need a different medicine. Long-term control medicines help you have fewer and milder attacks, but they don’t help you if you’re having an asthma attack.

Asthma medicines can have side effects, but most side effects are mild and soon go away. Ask your health-care provider about the side effects of your medicines.

The important thing to remember is that you can control your asthma. With your health-care provider’s help, make your own asthma management plan so that you know what to do based on your own symptoms. Decide who should have a copy of your plan and where he or she should keep it. You can learn more about asthma management plans from the American Academy of Family Physicians ( [external link]). Take your long-term control medicine even when you don’t have symptoms.

Important Asthma Triggers

Environmental Tobacco Smoke (Secondhand Smoke)

Environmental tobacco smoke is often called “secondhand smoke” because it is smoke that is breathed in not by a smoker but by a second person nearby. Parents, friends, and relatives of children with asthma should try to stop smoking and should never smoke around a person with asthma. They should only smoke outdoors and not in the family home or car. They should not allow others to smoke in the home, and they should make sure their child's school is smoke-free.

Dust Mites

Dust mites are in almost everybody’s home, but they don’t cause everybody to have asthma attacks. If you have asthma, dust mites may be a trigger for an attack. To help prevent asthma attacks, use mattress covers and pillow case covers to make a barrier between dust mites and yourself. Don’t use down-filled pillows, quilts, or comforters. Remove stuffed animals and clutter from your bedroom.

Outdoor Air Pollution

Pollution caused by industrial emissions and automobile exhaust can cause an asthma attack. Pay attention to air quality forecasts on radio and television and plan your activities for when air pollution levels will be low if air pollution aggravates your asthma.

Cockroach Allergen

Cockroaches and their droppings may trigger an asthma attack. Get rid of cockroaches in your home and keep them from coming back by taking away their food and water. Cockroaches are usually found where food is eaten and crumbs are left behind. Remove as many water and food sources as you can because cockroaches need food and water to survive. Vacuum or sweep areas that might attract cockroaches at least every 2 or 3 days. You can also use roach traps or gels to decrease the number of cockroaches in your home.


Furry pets may trigger an asthma attack. When a furry pet is suspected of causing asthma attacks, the simplest solution is to find the pet another home. If pet owners are too attached to their pets or are unable to locate a safe, new home for the pet, they should keep the pet out of the bedroom of the person with asthma.

Pets should be bathed weekly and kept outside as much as possible. People with asthma are not allergic to their pet’s fur, so trimming your pet’s fur will not help your asthma. If you have a furry pet, vacuum often to clean up anything that could cause an asthma attack. If your floors have a hard surface, such as wood or tile, and are not carpeted, damp mop them every week.


When mold is inhaled or breathed in, it can cause an asthma attack. Get rid of mold in all parts of your home to help control your asthma attacks. Keep the humidity level in your home between 35% and 50%. In hot, humid climates, you may need to use an air conditioner or a dehumidifier or both. Fix water leaks, which allow mold to grow behind walls and under floors.

Other Triggers

Strenuous physical exercise; some medicines; bad weather such as thunderstorms, high humidity, or freezing temperatures; and some foods and food additives can trigger an asthma attack.

Strong emotional states can also lead to hyperventilation and an asthma attack.

Learn what triggers your attacks so that you can avoid the triggers whenever possible and be alert for a possible attack when the triggers cannot be avoided.

Remember, you can control your asthma!

For more information, please contact:

CDC/National Center for Environmental Health
Division of Environmental Hazards and Health Effects

Other Environmental Hazards & Health Effects Topics