Asthma is a disorder that causes the airways of the lungs to swell and narrow, leading to wheezing, shortness of breath, chest tightness, and coughing.

Alternative Names

Bronchial asthma

Causes, incidence, and risk factors

Asthma is caused by inflammation in the airways. When an asthma attack occurs, the muscles surrounding the airways become tight and the lining of the air passages swells. This reduces the amount of air that can pass by.In sensitive people, asthma symptoms can be triggered by breathing in allergy-causing substances (called allergens or triggers).Common asthma triggers include:Animals (pet hair or dander)DustChanges in weather (most often cold weather)Chemicals in the air or in foodExerciseMoldPollenRespiratory infections, such as the common coldStrong emotions (stress)Tobacco smokeAspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs) provoke asthma in some patients.Many people with asthma have a personal or family history of allergies, such as hay fever (allergic rhinitis) or eczema. Others have no history of allergies.


Most people with asthma have attacks separated by symptom-free periods. Some people have long-term shortness of breath with episodes of increased shortness of breath. Either wheezing or a cough may be the main symptom.Asthma attacks can last for minutes to days, and can become dangerous if the airflow is severely restricted.Symptoms include:Cough with or without sputum (phlegm) productionPulling in of the skin between the ribs when breathing (intercostal retractions)Shortness of breath that gets worse with exercise or activity Wheezing, which: Comes in episodes with symptom-free periods in betweenMay be worse at night or in early morningMay go away on its ownGets better when using drugs that open the airways (bronchodilators)Gets worse when breathing in cold airGets worse with exerciseGets worse with heartburn (reflux)Usually begins suddenlyEmergency symptoms:Bluish color to the lips and faceDecreased level of alertness, such as severe drowsiness or confusion, during an asthma attackExtreme difficulty breathingRapid pulseSevere anxiety due to shortness of breathSweatingOther symptoms that may occur with this disease:Abnormal breathing pattern --breathing out takes more than twice as long as breathing inBreathing temporarily stopsChest painTightness in the chest

Signs and tests

Allergy testing may be helpful to identify allergens in people with persistent asthma. The doctor or nurse will use a stethoscope to listen to the lungs. Wheezing or other asthma-related sounds may be heard. However, lung sounds are usually normal between asthma episodes.Tests may include:Arterial blood gasBlood tests to measure eosinophil count (a type of white blood cell) and IgE (a type of immune system protein called an immunoglobulin)Chest x-rayLung function testsPeak flow measurements


The goals of treatment are:Control airway swellingStay away from substances that trigger your symptoms You and your doctor should work together as a team to develop and carry out a plan for eliminating asthma triggers and monitoring symptoms.There are two basic kinds of medication for treating asthma:Control drugs to prevent attacksQuick-relief (rescue) drugs for use during attacksEach type is described in more detail below. Long-term control drugs for asthma are used to prevent symptoms in people with moderate to severe asthma. You must take them every day for them to work. Take them even when you feel okay. Inhaled steroids prevent symptoms by preventing airway swelling. These work very well and are almost always the first choice.Long-acting beta-agonist inhalers also help prevent asthma symptoms. These drugs should be used together with an inhaled steroid drug. It may be easier to use an inhaler that contains both drugs.Other control drugs that may be used are:Leukotriene inhibitors (such as Singulair and Accolate)Omalizumab (Xolair)Cromolyn sodium (Intal) or nedocromil sodium (Tilade)Quick-relief (rescue) drugs work fast to control asthma symptoms:You take them when you are coughing, wheezing, having trouble breathing, or having an asthma attack. They are also called "rescue" drugs.They also can be used just before exercising to help prevent asthma symptoms that are caused by exercise.Tell your doctor if you are using quick-relief medicines twice a week or more to control your asthma symptoms. Your asthma may not be under control, and your doctor may need to change your dose of daily control drugs.Quick-relief drugs include:Short-acting bronchodilators (inhalers), such as Proventil, Ventolin, and XopenexYour doctor might prescribe oral steroids (corticosteroids) when you have an asthma attack that is not going away. These are medicines that you take by mouth as pills, capsules, or liquid. Plan ahead. Make sure you do not run out of these medications.A severe asthma attack requires a check-up by a doctor. You may also need a hospital stay, oxygen, breathing assistance, and medications given through a vein (IV).ASTHMA CARE AT HOMEKnow the asthma symptoms to watch out forKnow how to take your peak flow reading and what it meansKnow which triggers make your asthma worse and what to do when this happens.Asthma action plans are written documents for anyone with asthma. An asthma action plan should include:A plan for taking asthma medications when your condition is stableA list of asthma triggers and how to avoid themHow to recognize when your asthma is getting worse, and when to call your doctor or nurseA peak flow meter is a simple device to measure how quickly you can move air out of your lungs.It can help you see if an attack is coming, sometimes even before any symptoms appear. Peak flow measurements can help show when medication is needed, or other action needs to be taken.Peak flow values of 50% - 80% of a specific person's best results are a sign of a moderate asthma attack, while values below 50% are a sign of a severe attack.

Expectations (prognosis)

There is no cure for asthma, although symptoms sometimes improve over time. With proper self management and medical treatment, most people with asthma can lead normal lives.


The complications of asthma can be severe. Some include:DeathDecreased ability to exercise and take part in other activitiesLack of sleep due to nighttime symptomsPermanent changes in the function of the lungsPersistent coughTrouble breathing that requires breathing assistance (ventilator)

Calling your health care provider

Call for an appointment with your health care provider if asthma symptoms develop.Call your health care provider or go to the emergency room if:An asthma attack requires more medication than recommendedSymptoms get worse or do not improve with treatmentYou have shortness of breath while talkingYour peak flow measurement is 50% - 80% of your personal bestGo to the emergency room if the following symptoms occur:Drowsiness or confusionSevere shortness of breath at restA peak flow measurement is less than 50% of your personal bestSevere chest painBluish color to the lips and faceExtreme difficulty breathingRapid pulseSevere anxiety due to shortness of breath


You can reduce asthma symptoms by avoiding known triggers and substances that irritate the airways.Cover bedding with "allergy-proof" casings to reduce exposure to dust mites.Remove carpets from bedrooms and vacuum regularly.Use only unscented detergents and cleaning materials in the home.Keep humidity levels low and fix leaks to reduce the growth of organisms such as mold.Keep the house clean and keep food in containers and out of bedrooms -- this helps reduce the possibility of cockroaches, which can trigger asthma attacks in some people.If a person is allergic to an animal that cannot be removed from the home, the animal should be kept out of the bedroom. Place filtering material over the heating outlets to trap animal dander.Eliminate tobacco smoke from the home. This is the single most important thing a family can do to help a child with asthma. Smoking outside the house is not enough. Family members and visitors who smoke outside carry smoke residue inside on their clothes and hair -- this can trigger asthma symptoms.Persons with asthma should also avoid air pollution, industrial dusts, and other irritating fumes as much as possible.


Lugogo N, Que LG, Fertel D, Kraft M. Asthma. In: Mason RJ, Broaddus VC, Martin TR, et al. Murray & Nadel's Textbook of Respiratory Medicine. 5th ed. Philadelphia, Pa: Saunders Elsevier; 2010:chap 38.Brozek JL, Bousquet J, Baena-Cagnani CE, Bonini S, Canonica GW, Casale TB, et al. Allergic Rhinitis and its Impact on Asthma (ARIA) guidelines: 2010 revision. J Allergy Clin Immunol. 2010 Sep;126(3):466-76.National Asthma Education and Prevention Program Expert Panel Report 3: Guidelines for the Diagnosis and Management of Asthma. Rockville, MD. National Heart, Lung, and Blood Institute, US Dept of Health and Human Services; 2007. NIH publication 08-4051.Wechsler ME. Managing asthma in primary care: putting new guideline recommendations into context. Mayo Clin Proc. 2009;84:707-717.Fanta CH. Asthma. N Engl J Med. 2009;360:1002-1014.

Review Date: 7/9/2012
Reviewed By: David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc., and Denis Hadjiliadis, MD, Assistant Professor of Medicine, Division of Pulmonary, Allergy and Critical Care, University of Pennsylvania, Philadelphia, PA.
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