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Medically reviewed by Leigh Ann Anderson, PharmD. Last updated on Jan 20, 2022.

What Causes Asthma?

Asthma is a common inflammatory lung disease which can lead to attacks of wheezing, shortness of breath, chest tightness, and coughing. When an asthma attack occurs, the muscles surrounding the airways become tight and the lining of the air passages swell and narrow. This reduces the amount of air that can pass through the airways and can lead to wheezing sounds, coughing, chest tightness and shortness of breath. Asthma that is triggered by exercise is known as exercise-induced asthma and has similar symptoms to traditional asthma.

Most people with asthma have wheezing attacks separated by symptom-free periods. Some patients have long-term shortness of breath with episodes of increased shortness of breath. In others, a cough may be the main symptom. Asthma attacks can last from minutes to days and can become dangerous if the airflow becomes severely restricted.

In sensitive individuals, asthma symptoms can be triggered by breathing in allergy-causing substances (called allergens or triggers). Identifying triggers and avoiding them are essential to asthma control. Asthma triggers might include:

  • Pet dander
  • Dust mites
  • Cockroach allergens
  • Molds
  • Pollens

Asthma symptoms can also be triggered by:

  • Respiratory infections
  • Exercise (exercise-induced asthma)
  • Cold air
  • Tobacco smoke and other pollutants
  • Stress
  • Food
  • Drug allergies

Aspirin and other non-steroidal anti-inflammatory medications (NSAIDS) such as ibuprofen or naproxen, and blood pressure medications known as beta blockers can also provoke asthma in some patients.

Many people with asthma have an individual or family history of allergies, such as hay fever (allergic rhinitis) or eczema. Others have no history of allergies. Desensitization procedures, such as allergy injections may be options for patients who cannot avoid triggers.

Common Symptoms of Asthma

Symptoms of asthma include:

  • Wheezing (a whistling sound when exhaling (a common sign of asthma in children)
  • Usually begins suddenly
  • Comes in episodes
  • May be worse at night and interfere with sleep; may worsen in early morning
  • Gets worse with cold air, exercise, and heartburn
  • May go away on its own
  • Is relieved by bronchodilators (drugs that open the airways)
  • Cough with or without sputum (phlegm) production
  • Shortness of breath that gets worse with exercise or activity
  • Intercostal retractions (pulling of the skin between the ribs when breathing)
  • Nasal flaring
  • Chest pain
  • Tightness in the chest
  • Abnormal breathing pattern --breathing out takes more than twice as long as breathing in.

How Is Asthma Diagnosed?

Allergy testing may be helpful in identifying allergens in patients with persistent asthma. Common allergens include pet dander, dust mites, cockroach allergens, molds, and pollens. Common respiratory irritants include tobacco smoke, pollution, and fumes from burning wood or gas.

The doctor will use a stethoscope to listen to the lungs. Asthma-related sounds may be heard. However, lung sounds are usually normal between asthma episodes.

Tests may include:

  • Lung function tests
  • Peak flow measurements
  • Chest x-ray
  • Blood tests, including eosinophil count (a type of white blood cell)
  • Arterial blood gas

Should I See a Doctor About My Asthma?

Call for an appointment with your health care provider if you or your child experience mild asthma symptoms (to discuss treatment options).

Call your health care provider (or go to the nearest emergency room) for:

  • Moderate shortness of breath (shortness of breath with talking, peak flow 50-80% of personal best)
  • If symptoms worsen or do not improve with treatment
  • An attack requires more medication than recommended in the prescription

Call 911 or other emergency treatment for severe shortness of breath (shortness of breath at rest, peak flow less than 50% of personal best), if drowsiness or confusion develops, or for severe chest pain. 

Peak Flow Meter

A peak flow meter is a simple and inexpensive device which can be used to monitor your lung function. It can be used at home to help you predict an upcoming attack and to take appropriate action, sometimes even before any symptoms appear. If you are not monitoring asthma on a regular basis, an attack can take you by surprise.

Peak flow measurements can help show when medication is needed, or when other action needs to be taken. Peak flow values of 50% to 80% of an individual's personal best results indicate a moderate asthma attack, while values below 50% indicate a severe attack.

Emergency Symptoms of Asthma

  • Extreme difficulty breathing
  • Breathing temporarily stops
  • Bluish color to the lips and face
  • Severe anxiety due to shortness of breath
  • Rapid pulse
  • Sweating
  • Decreased level of alertness, such as severe drowsiness or confusion, during an asthma attack

Seek immediate medical care by call 911 if any of these symptoms appear.

Asthma and Severe Allergic Reactions

If you have asthma and a severe allergic reaction (for example, to insects, certain foods like peanuts or shellfish, latex, or medications) speak to your doctor about your action plan for a severe allergy. Patients with a diagnosis of asthma or other chronic lung disease may have more severe respiratory problems during a severe allergic reaction or anaphylaxis. Uncontrolled asthma can worsen breathing difficulties during a severe allergic reaction.  

Breathing patterns during a severe allergic reaction may resemble an asthma attack, causing confusion about whether the person is having an asthma attack or difficulty breathing from an allergic reaction.

Your doctor may want you to use an epinephrine (auto-injector or other prescribed dosage form) first if there is any confusion about whether the breathing difficulty is due to asthma or an allergic reaction. After use of epinephrine, use a prescribed fast-acting asthma inhaler, or other treatment as recommended by your doctor for acute asthma attacks, and call 911 or go to the emergency room immediately.

Antihistamines like diphenhydramine (Benadryl) and asthma inhalers like albuterol (ProAir, Ventolin) do not fully treat an anaphylactic reaction. These medications should not be substituted for epinephrine.

Patients with severe allergic reactions who also have asthma should carry two epinephrine auto-injectors (such as EpiPenAdrenaclick, Adrenalin, Auvi-QEPIsnap, or generic versions).

Some brands of epinephrine auto-injector may contain meta-bisulfite which can lead to allergic reactions and bronchospasm in those with a history of asthma. However, epinephrine is the preferred treatment for serious allergic reactions or other emergency situations even though this product contains sodium metabisulfite.

How is Asthma Treated?

Asthma treatment is aimed at avoiding known allergens and respiratory irritants, and controlling symptoms and airway inflammation through medication. The main goals are to restore normal airway function and prevent severe acute attacks.

Medication for asthma is either delivered by inhalation, orally or parenterally (by injection).

Inhalation is the preferred route of administration as this allows the drug to be delivered directly into the airways in smaller doses. This causes fewer side effects than if given orally or by injection. When delivered by inhalation, bronchodilators also have a faster onset of action and give better protection from constriction of the lung bronchi.

Patients with persistent asthma should use preventative medicine such as inhaled corticosteroids on a regular basis to prevent asthma attacks. Medication is added in a step-up progression depending on the severity and frequency of attacks. It is also important to step-down the treatment when control is good.

Patients should have a personalized asthma action plan developed in conjunction with their health care provider to control their asthma. Long-term control medications and short acting medications are an important part of every asthma action plan.

Keep your regularly scheduled appointments with your doctor to review your asthma and treatments. Your healthcare provider may have you keep a diary of your symptoms, your use of the rescue inhaler, or other triggers or complications.

If your asthma is well-controlled, you may see the doctor once or twice a year; if symptoms worsen you may need to go more frequently. Let your doctor know if your asthma symptoms get worse at any time.

Long-Term Control Medications

Long-term control medications are used on a regular basis to prevent attacks. These are not appropriate as treatment during an acute asthma attack. Long-term treatment includes inhaled corticosteroids, long-acting bronchodilators, leukotriene inhibitors, mast cell stabilizers, and interleukin inhibitors. Oral theophylline can also be used as a preventive in patients with chronic asthma, but it isn't used as often as in the past.

Inhaled Corticosteroids

Inhaled corticosteroids help to decrease inflammation and narrowing of the airways. These agents must be used regularly to get maximum benefit, and are recommended to help prevent asthma symptoms, reduce the need for rescue inhalers, and decrease the risk of serious attacks, and improve the quality of life.

Most inhaled corticosteroids are used once or twice daily. In case of exposure to a trigger, or to prevent exercise-induced asthma, a rescue inhaler (bronchodilator) can still be used as needed. However, regular use of a bronchodilator may mean that the dose of the inhaled corticosteroid is not optimal and that your asthma is worsening, so see your doctor.

Common side effects of inhaled corticosteroids include: oral candidiasis (thrush), sore throat, or hoarse voice. Rinsing your mouth or using a spacer can often help to prevent oral side effects of inhaled corticosteroids.

Brand Name Generic Name
Aerospan HFA (discontinued) flunisolide (discontinued)
Alvesco ciclesonide
Asmanex Twisthaler, Asmanex HFA mometasone
Flovent Diskus, Flovent HFA, Arnuity Elipta, ArmonAir Digihaler fluticasone
Pulmicort Flexhaler, Pulmicort Respules budesonide
Qvar RediHaler beclomethasone

Long-Acting Beta-2 Agonist (LABA) Bronchodilators

Long-acting beta-2 agonist (LABA) bronchodilators used for asthma relax muscles in the airways and improve breathing. Although good asthma control may be established with LABAs, inhaled steroid therapy should NOT be discontinued. In fact, LABAs should not be used in patients with asthma without use of a long-term asthma control medication such as a corticosteroid.

High doses of inhaled corticosteroids may not be needed when combined with a LABAs. Most LABAs and corticosteroids are used as commercially available combination products to ease administration.

Brand Name Generic Name
Foradil formoterol
Serevent salmeterol

Leukotriene Modifiers

Leukotriene modifiers are oral tablets used once or twice daily to treat and prevent chronic asthma and allergic rhinitis. They may be used in combination with an inhaled corticosteroid for an enhanced effect. They can also be used to prevent symptoms due to triggers or exercise, but must be taken at least 3 hours before exposure. If you already take a leukotriene modifier to prevent asthma or allergy symptoms, do not use an extra dose to treat exercise-induced asthma. All patients should still have a short-acting β-agonist like albuterol available for rescue inhalation.

Leukotriene modifiers block an inflammatory substance called leukotriene. The release of leukotrienes causes airway constriction, increased mucus production, swelling and inflammation in the lungs resulting in the characteristic wheezing and shortness of breath in asthma. Leukotriene modifiers open narrowed airways, decrease inflammation, and lower the mucous production.

Rare but possibly serious side effects of leukotriene modifiers include mood changes and risk for depression. Singulair now carries a Boxed Warning, the FDA's most stringent safety warning, for serious neuropsychiatric events.

Common side effects include upper respiratory infection, fever, headache, sore throat, and cough, among others.

Brand Name Generic Name
Accolate zafirlukast
Singulair montelukast
Zyflo CR zileuton

Mast Cell Stabilizers

Mast cell stabilizers work by stabilizing mast cells and preventing them from releasing their irritating chemicals. Some forms of recurrent or chronic asthma are due to the release of irritating chemicals from mast cells located in the bronchial tubes.

Cromolyn, usually given as a nebulized solution, should not be added to treatment during an acute episode; therapy should be started once asthma is controlled, the airway is cleared, and the patient is able to inhale adequately.

Brand Name Generic Name
Brand discontinued cromolyn

Monoclonal Antibodies 

Tezspire (tezepelumab-ekko) is used as add-on maintenance treatment of adults and children aged 12 years and older with severe asthma. It is the only biologic approved for severe asthma with no phenotype (e.g. eosinophilic or allergic) or biomarker limitation. Tezspire is administered once every four weeks by a health care professional via a subcutaneous (under the skin) injection. It is classified as a thymic stromal lymphopoietin (TSLP) blocker, human monoclonal antibody (IgG2λ)

Xolair (omalizumab) is an anti-IgE therapy that helps decrease allergic response in the body and is administered by injection to patients with severe asthma. It is usually given after other asthma medications have been unsuccessful, and in patients who cannot avoid severe asthma triggers.

Brand Name Generic Name
Tezspire tezepelumab-ekko
Xolair omalizumab


Methylxanthines are rarely used anymore for asthma. When used, they are given orally, rectally or intravenously. These are regarded more as relievers but oral theophylline may be given long-term as well.

Theophylline has a narrow therapeutic index which means the level required for it to give therapeutic benefit is close to the toxic level. Patients should be monitored for serious toxic effects such as tachycardia (fast heart rate) and persistent vomiting. Once therapy is started and the patient is stabilized, the same theophylline preparation should be used. Care should also be taken when medicines which interact with theophylline are added or withdrawn.

Brand Name Generic Name
Brand discontinued aminophylline
Elixophyllin, Theo-24 theophylline

Antimuscarinic Bronchodilators

Antimuscarinic bronchodilators block muscarinic receptors in the bronchial smooth muscle and cause bronchodilation. Compared to beta-2 agonists, these have a slower onset of action but last longer. They may be useful if other therapy does not adequately control symptoms.

Spiriva Respimat is a long-acting muscarinic antagonist used to prevent asthma attacks in adults and children who are at least 6 years old. It might be appropriate for patients with moderate-persistent asthma when combined with an inhaled glucocorticoid. This can be useful for patients intolerant of long-acting beta agonists (LABAs).

Spiriva Respimat is not a rescue medicine for sudden breathing problems. Use only a fast-acting inhalation medicine (like albuterol) for a bronchospasm attack.

Antimuscarinic agents are approved and used more often in patients with chronic obstructive pulmonary disease (COPD).

Brand Name Generic Name
Spiriva Respimat tiotropium

Short-Acting Beta-2 Agonist Bronchodilators

Short-acting beta-2 agonists (SABAs) relax muscles in the airways rapidly and improve breathing. They have a faster onset and a shorter duration of action compared to the long acting beta-2 agonist (LABA) bronchodilators. These agents are often referred to as "quick acting relievers" or "rescue medications".

Patients with mild, intermittent asthma may only need these medications occasionally. Patients with exercise-induced asthma use them 5 to 20 minutes prior to the activity. These agents are not meant for regular, continuous use. If symptoms occur regularly 2 days or more per week, a physician should be consulted to determine an appropriate maintenance medication treatment regimen.

Common side effects of short-acting beta-2 agonists can include: nervousness, fast heart rate, and anxiety after use.

Brand Name Generic Name
Accuneb (Nebulizing Solution), ProAir Digihaler, ProAir HFA, ProAir Respiclick, Proventil HFAVentolin HFA (Inhalers) Vospire ER (oral) albuterol
Brethine (brand discontinued) terbutaline
Xopenex (nebulizing solution), Xopenex HFA (inhaler) levalbuterol

Another type of inhaled short-acting agent known as epinephrine (Primatene Mist) is available without a prescription, but many doctors do not recommend its use. Epinephrine oral inhalation is in a class of medications known as alpha- and beta-adrenergic agonists (sympathomimetic agents). This inhaled product is NOT used to treat severe allergic reactions, such as food or bees stings; injected epinephrine (for example, EpiPen) is used for those emergencies.

Talk to your doctor if you think you have undiagnosed asthma symptoms. The FDA does not recommend Primatene Mist in patients without a diagnosis. Fast-acting or maintenance prescription asthma medicines are more effective and possibly better tolerated, if needed. 

Learn more: How is the new Primatene Mist different to the old formulation?

Oral or IV Corticosteroids

When inhaled agents are not sufficient for asthma control, a course of oral corticosteroids might be given short-term (5 to 10 days) during asthma exacerbations or given intravenously (IV) during severe acute attacks.

Common side effects can include enhanced energy, difficulty sleeping, anxiety, increased appetite, altered blood sugar levels, and weight gain.

Brand Name Generic Name
Prednisone, Prednisone Intensol, Rayos prednisone
Millipred, OraPred ODTPediapred prednisolone
Depo-Medrol, Solu-Medrol methylprednisolone
Cortef, Solu-Cortef hydrocortisone

Other Adrenoreceptor Agonists

Adrenoreceptor agonists such as ephedrine and metaproterenol are used less frequently than the selective beta-2 agonists, as they are more likely to cause arrhythmias (abnormal heart rhythms) and other side effects. These should be avoided.

Brand Name Generic Name
Generic Only (Tabs & Elixir) ephedrine
Brand discontinued metaproterenol

Combination Inhalers

There are several inhalers which have 2 or 3 types of medications for the treatment of asthma or COPD. These include various combinations of short-acting beta 2-agonists (SABAs), long-acting beta-2 agonists (LABAs), long-acting antimuscarinic antagonists (LAMAs oranticholinergics), or corticosteroids.

Brand Name Generic Name
Advair Diskus, Advair HFA, AirDuo Digihaler, AirDuo Respiclick, Wixela Inhub fluticasone and salmeterol
Symbicort budesonide and formoterol
Dulera formoterol and mometasone
Breo Ellipta fluticasone and vilanterol
Trelegy Ellipta fluticasone, umeclidinium, and vilanterol

Interleukin (IL) Inhibitors

Some patients with asthma have a subtype known as "eosinophilic asthma". Eosinophil asthma is associated with more severe asthma symptoms linked to certain while blood cells (eosinophils) in your body. Interleukin inhibitors (IL inhibitors) help to reduce levels of this white blood cell that may contribute to inflammation and asthma symptoms. These drugs are not used for the relief of acute breathing problems.

  • A common target for eosinophilic asthma is the IL-5 (interleukin-5) receptor. The IL-5 receptor is found on the surface of eosinophils and basophils (both a type of white blood cell).
  • These drugs are given by injection for the maintenance (long-term) treatment of patients with severe asthma. They are used with other asthma medicines.
  • Fasenra is used for the treatment of patients aged 12 years and older, Nucala for 6 years and older, and Cinqair for 18 years and older. 
  • Dupixent is approved by the FDA as add-on therapy for moderate-to-severe asthma in patients aged 6 years of age and older with an eosinophilic phenotype or with oral corticosteroid-dependent asthma. Dupixent acts at the unique interleukin receptors IL-4 and IL-13.
Brand Name Generic Name
Cinqair reslizumab
Dupixent dupilumab
Fasenra benralizumab
Nucala mepolizumab

Bottom Line

  • Asthma is a common inflammatory (swelling) lung disease which can lead to attacks of wheezing, shortness of breath, chest tightness, and coughing. It occurs in adults and children. Some patients may have more severe symptoms than others, and treatments can vary.
  • Each patient should have an established action plan for treatment and exacerbations developed with their healthcare provider.
  • The mainstay of treatment for asthma is long-term asthma control medications, such as inhaled corticosteroids, leukotriene modifiers or combination inhalers. A quick-acting relief inhaler, such as albuterol, should always be close at hand for sudden breathing problems.
  • Patients may also need to use other medicines for more severe symptoms, such as oral or IV corticosteroids or biologics known as interleukin inhibitors.

See Also


Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.