Health Library Explorer
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A-Z Listings Contact Us


What is asthma?

Asthma is a long-term (chronic) lung disease. The airways react to triggers (allergens and irritants). This makes it hard to breathe. With exposure to triggers, these changes occur:

  • The airways become swollen and inflamed.
  • The muscles around the airways tighten.
  • More mucus is made. This leads to mucus plugs.

All of these changes make the airways narrow. This makes it hard for air to go out of the lungs. And fresh oxygen can't get into the body.

What causes asthma?

Experts don't know the exact cause of asthma. They believe it is partly inherited. The environment, infections, and chemicals released by the body also play a role.

Exercise causes symptoms in many people with asthma. Symptoms can occur during exercise. They can also occur shortly after exercise. In some people, stress or strong feelings can cause asthma symptoms.

All of these may be asthma triggers:


Respiratory problem

  • Pollens (trees, grasses, and weeds)
  • Mold
  • Pets
  • Dust and dust mites
  • Cockroaches
  • Mice
  • Nasal allergies
  • Sinus infections
  • The flu
  • Viral infections, including the common cold



  • Strong odors from perfumes, household cleaners, cooking fumes, paints, and varnishes
  • Chemicals (gases, fumes)
  • Air pollution
  • Changing weather conditions (temperature, barometric pressure, humidity, and strong winds)
  • Smoke (tobacco-inhaled or secondhand)
  • Aspirin
  • NSAIDs (nonsteroidal anti-inflammatory drugs) such as ibuprofen

Other conditions

  • GERD (gastroesophageal reflux)
  • Sleep apnea
  • Overweight
  • Depression


  • Exercise, especially in cold weather
  • Strong feelings that go along with laughing or crying

Who is at risk for asthma?

It is most common in:

  • Children and teens ages 5 to17
  • People living in cities

Other factors include:

  • Personal or family history of asthma or allergies
  • Exposure to secondhand tobacco smoke
  • Children with a family history of asthma
  • Children who have allergies or atopic dermatitis
  • Children exposed to secondhand and tobacco smoke

What are the symptoms of asthma?

Symptoms include:

  • Trouble breathing or shortness of breath
  • Chest tightness
  • Wheezing or a whistling sound when breathing
  • Coughing
  • Breathing becomes harder and may hurt
  • Talking and sleeping may be harder with severe symptoms

How is asthma diagnosed?

Your healthcare provider will take your health history and give you a physical exam. You will also have other tests. An important test is spirometry.

A spirometer is a device used to find out how well the lungs are working. It measures the amount and speed of air breathed out.

Other tests may also be done to check for conditions such as allergies.

How is asthma treated?

Treatment will depend on your symptoms, age, and general health. It will also depend on how severe the condition is.

There is no cure for asthma. It can often be controlled by staying away from triggers. And by taking medicines as prescribed by your healthcare provider.

Watching symptoms is a key part of asthma care. So is knowing what to do if symptoms get worse. Experts recommend making an Asthma Action Plan with your provider.

Medicines for asthma

The 2 types of asthma medicines are long-term control and short-term (quick-relief) medicines. Long-term control medicines are often taken every day. They help prevent symptoms. Quick-relief medicines calm asthma symptoms fast. But they only last for a short time. You may take either type of medicine alone. Some people take both.

Your healthcare provider should regularly check and adjust your medicines as needed.

Long-term control medicines

At first, it may take a few weeks for long-term control medicines to work. You must take these medicines every day. These medicines include:

  • Anti-inflammatory medicines.  These medicines reduce or prevent airway swelling.
  • Bronchodilators. These medicines relax muscles around the airways.
  • Leukotriene modifiers. These medicines block the action of certain chemicals (leukotrienes). These chemicals cause airway inflammation and narrowing. 
  • Anti-IgE (omalizumab). This medicine reduces allergic reactions. It is a shot (injection) given once or twice monthly. It is often used when asthma is harder to control.
  • Anti-IL-5 (Interleukin-5) agents. These medicines are given by injection in a provider's office. They block a chemical in the body called IL-5.

Quick-relief medicines

Quick-relief medicines quickly relax the muscles around the airways. But the relief only lasts about 2 to 3 hours.

These medicines may include:

  • Inhaled short-acting beta2-agonists. These help relax muscles around the airways.
  • Inhaled anticholinergics. These are medicines that block a certain chemical (acetylcholine). This chemical contracts the muscles. It also causes more mucus in the airways.

Inhalation devices for asthma

Inhaled medicines go right to the lungs. There have fewer side effects than medicines taken by mouth. Inhaled medicines may be anti-inflammatory or bronchodilating, or both. The devices used are:

  • Metered-dose inhalers (MDI). This is the most common type of inhaler. It uses a chemical to push the medicine out of the inhaler. MDIs are held in front of or put into the mouth. Then the medicine is released in puffs. Or they may be used with a spacer device.
  • Nebulizers. This device sprays a fine mist of medicine. This is done through a mask using air under pressure, or an ultrasonic machine. A mouthpiece or mask is connected to a machine by plastic tubing to deliver medicine.
  • Dry powder or rotary inhalers. These inhalers deliver powered medicine as you breathe.

Living with asthma

Staying away from triggers is key in managing asthma. Triggers may be allergens, irritants, other health problems, exercise, medicines, and strong emotions. The following can help you limit your exposure:


  • Dust. Dust is the most common year-round allergen. The allergy is caused by tiny dust mites. Dust mites are found in mattresses, carpets, and fabric-covered (upholstered) furniture such as sofas and chairs. They live best in warm, humid conditions. It's important to limit your exposure. Take extra care in the bedroom. Put dust mite covers on your mattress, box spring, and pillows.
  • Pollens.  You may be allergic to pollen. If so, during pollen season keep all car and house windows closed. Use air conditioning. If you are outside, shower, wash your hair, and change clothes when you go inside. 
  • Pets. Pets that have fur or feathers often cause allergies. If you have pets, try not to touch them. If you do pet or handle them, wash your hands afterward. Keep pets off your bed and out of your bedroom. Have someone brush and bathe your pet often.
  • Mold and mildew. These can trigger asthma. When outside, stay away from damp, shady areas. Use exhaust fans when cooking or bathing. Keep indoor humidity below 45%. And drain and clean your dehumidifier often.


Exercise is a common asthma trigger. But don't limit sports or exercise unless a healthcare provider tells you to. Exercise is good for your health and lungs. Swimming, golf, and karate are good choices if you have asthma. Always warm up before exercise. And cool down after. Ask your provider about using your quick-relief medicine before starting exercise.


If you smoke, quit.

Stay away from smoke. Don’t use wood stoves or kerosene heaters. Also stay away from strong perfumes, cleaning products, fresh paint, and other things with strong odors.


Some medicines can make asthma symptoms worse. These medicines include aspirin, NSAIDs (nonsteroidal anti-inflammatory drugs), and beta-blockers. Talk with your provider about your asthma history and medicine use.

Other health problems

Some health problems can make it harder to control asthma. These include:

  • Respiratory infections such as colds and the flu
  • GERD (gastroesophageal reflux) and heartburn
  • Being overweight
  • Sleep apnea
  • Depression

Work with your provider to treat any of these problems.

Strong emotions

The strong feelings that go with laughing and crying can trigger asthma symptoms. You can learn how to better manage your emotions.

Key points about asthma

  • Asthma is a long-term (chronic) lung disease.
  • Triggers irritate sensitive airways. This makes it hard to breathe.
  • Staying away from triggers is an important part of treatment.
  • Long-term medicines control symptoms. They are taken every day, even when you feel well.
  • Rescue medicines provide quick symptom relief. But they are short-term.

Next steps

Tips to help you get the most from a visit to your healthcare provider:

  • Know the reason for your visit and what you want to happen.
  • Before your visit, write down questions you want answered.
  • Bring someone with you to help you ask questions and remember what your provider tells you.
  • At the visit, write down the name of a new diagnosis, and any new medicines, treatments, or tests. Also write down any new instructions your provider gives you.
  • Know why a new medicine or treatment is prescribed, and how it will help you. Also know what the side effects are.
  • Ask if your condition can be treated in other ways.
  • Know why a test or procedure is recommended and what the results could mean.
  • Know what to expect if you do not take the medicine or have the test or procedure.
  • If you have a follow-up appointment, write down the date, time, and purpose for that visit.
  • Know how you can contact your provider if you have questions.
Online Medical Reviewer: Alan J Blaivas DO
Online Medical Reviewer: Daphne Pierce-Smith RN MSN CCRC
Online Medical Reviewer: Paula Goode RN BSN MSN
Date Last Reviewed: 10/1/2018
© 2000-2019 The StayWell Company, LLC. 800 Township Line Road, Yardley, PA 19067. All rights reserved. This information is not intended as a substitute for professional medical care. Always follow your healthcare professional's instructions.
Powered by StayWell
About StayWell | StayWell Disclaimer