Encyclopedia / A / Asthma


What Is Asthma?

Bronchial asthma is a condition caused by chronically hyper-reactive and inflamed airways, punctuated by acute episodes of reversible narrowing of the airways.

For reasons not fully understood, those suffering from asthma may be particularly sensitive to irritants such as dust, cold air, and viral infections. Such irritants may periodically cause bronchospasm—contraction of the muscles within the bronchi, which are the airways between the trachea and the air sacs of the lungs—and provoke increased mucus production. Attacks may be mild or severe and may last anywhere from a few minutes to days. The World Health Organization estimates that 235 million people worldwide are affected by asthma.

Asthma is the most common chronic disease in children, and its prevalence appears to be rising in the United States. The Centers for Disease Control and Prevention (CDC) reports that the number of people with asthma increased by 28% from 2001 to 2011, and that during this time period, asthma rates rose by almost 50% in black children. Currently, 7.0% of all adults and 8.3% of all children in the United States have asthma, making it one of the most common chronic conditions. Fifty percent of children with asthma outgrow the condition as they get older and the bronchial passages widen.

Who gets Asthma?

Asthma may develop at any age, and affects people of all races and ethnicities. According to 2011 data from the CDC, asthma affects 7.4% of whites, 9.9% of blacks, and 5.9% of Hispanics/Latinos in the United States.


  • Sudden difficulty with breathing.

  • Rapid, shallow breathing that is eased by sitting up.

  • A sense of suffocation.

  • Painless tightness in the chest.

  • Coughing, possibly with the production of thick, clear or yellow sputum (symptoms may mimic a viral infection in young children).

  • Severe symptoms can include difficulty speaking, clenched or constricted neck muscles, rapid pulse, sweating, and anxiety.

  • Emergency symptoms include a bluish tinge in the face or lips, extremely labored breathing, mental confusion, a profound feeling of exhaustion.

Causes/Risk Factors

  • Asthma is generally caused by allergy to some foreign substance (allergen). Hence, attacks can be triggered by exposure to environmental allergens or irritants that include dust mites, cockroaches, airborne pollen and molds, plants, pet dander, tobacco smoke, air pollution or fumes.
  • Certain medications, including over-the-counter pain relievers such as aspirin, ibuprofen, as well as prescription beta-blockers, can trigger asthma attacks.
  • Sulfites, chemicals commonly used to preserve foods in tuna, salads, dried fruit, and beverages, including wine and grape juice, can trigger asthma attacks.
  • Exercise, emotional excitement or stress may induce an asthma attack.
  • Cold, dry air may induce an asthma attack.
  • Respiratory illnesses including bronchitis and other lung infections.
  • Other medical conditions such as gastroesophageal reflux disease, pregnancy, and menstruation can affect asthma. Heart disease and chronic obstructive pulmonary disease may also be associated with asthma-related complications.
  • Family history of asthma.

What If You Do Nothing?

Although there is no cure for asthma, trying to ignore asthma symptoms, however mild, is a mistake. The breathing difficulties will prevent you from living a full and active life—and untreated asthma can be serious. Each year in the United States, 1.8 million people are treated in hospital emergency departments for asthma-related symptoms. While seldom fatal, asthma is a chronic disease that needs constant monitoring and medical attention.


  • Your doctor will conduct a physical examination.
  • Allergy skin tests will be performed. A small amount of a suspected allergen will be injected just under the skin. If the area turns red or itchy, or a lump appears, you may be allergic to that substance.
  • Chest x-rays are frequently required.
  • Blood samples.
  • Pulmonary-function tests that the strength and efficiency of your lungs will be performed.
  • Keep a diary. Record the occurrence and severity of asthma attacks to see if there are any patterns or changes.

Medical treatment can be determined by asthma severity, which falls into four different categories:

  • Mild intermittent asthma:

  • Symptoms occur, on average, less than twice a week.

  • No symptoms (asymptomatic) and normal peak expiratory flow (PEF) rate between attacks (exacerbations).

  • Brief exacerbations last from a few hours to a few days and vary in intensity.

  • Nighttime symptoms occur less than twice a month.

  • FEV1 or PEF greater than 80 percent of the predicted value.

  • PEF variability of less than 20 percent.

  • Mild persistent asthma:

  • Symptoms occur more than twice a week.

  • Exacerbations affect activity

  • Nighttime symptoms occur more than twice a month

  • FEV1 or PEF greater than 80 percent of the predicted value.

  • PEF variability of between 20% to 30%.

  • Moderate persistent asthma:

  • Daily symptoms.

  • Daily use of a short-acting beta2 agonist.

  • Exacerbations affect activity.

  • Exacerbations occur more than twice a week or persist for days.

  • Nighttime symptoms occur more than once a week.

  • FEV1 or PEF greater than 60 percent but less than 80 percent of the predicted value.

  • PEF variability greater than 30 percent.

  • Severe persistent asthma:

  • Continual symptoms.

  • Exacerbations limit physical activity.

  • Frequent exacerbations.

  • Frequent nighttime symptoms.

  • FEV1 or PEF less than 60 percent of the predicted value.

  • PEF variability greater than 30 percent.


  • Bronchodilator inhalers. These devices help open the airways during an asthma attack. However, it is not recommended for regular use as overreliance on it may be harmful.
  • Inhaled corticosteroid drugs. These anti-inflammatory drugs are commonly used to control the underlying inflammation in the airways.
  • Oral bronchodilator drugs. These drugs include long-acting theophylline or an antileukotriene agent, such as zafirlukast, to help reduce asthma attack frequency. Inhaled long-acting bronchodilators are sometimes used as well.
  • Peak flow meter. This small, handheld device measures airflow to monitor lung function. Peak airflow will go down hours, and sometimes even a day or two, before an attack, so the meter can serve as an early warning system and allow for medication changes before symptoms worsen significantly.
  • Corticosteroid pills. These may be prescribed briefly during severe attacks, which at times may require an emergency room visit or hospitalization.
  • Desensitizing injections. Under a physician's care in a controlled setting, the physician injects small amounts of the allergen into the skin, and may gradually build up to larger amounts. The goal is to rehabilitate the immune system and "reprogram" its reaction to the allergen.

Self-management and control of your personal environment, particularly your home, can have an impact on asthma symptoms.

  • If you have pets, keep them out of bedrooms.
  • Keep bathrooms clean and dry to reduce mold.
  • Remove houseplants because molds grows in the soil.
  • Avoid sleeping or lying on upholstered furniture or on a carpet or rug.
  • Dust and vacuum frequently.
  • Encase mattresses and pillows in an impermeable barrier.
  • Reducing indoor humidity to less than 50 percent.
  • Remove carpets from bedroom or sleeping area, and remove carpets covering concrete floors. In children's rooms, remove stuffed animals, which can trap dust mites.
  • Wash pillowcases and bedding weekly in water above 130° F. Dry freshly laundered clothes promptly.


  • Identify allergens in home and work environments, and eliminate them if possible.
  • Don’t smoke; avoid secondhand smoke.
  • Reduce the amount of dust in your home: vacuum regularly, encase mattresses with plastic to discourage dust-mite infestation, and eliminate carpets that are difficult to clean.
  • Avoid foods such as milk, nuts, chocolate, fish, and medicines such as aspirin or ibuprofen that have been associated with asthma.
  • Drink at least eight glasses of liquid a day to keep mucus secretions loose.
  • Each morning, practice deep breathing by inhaling fully, bending over with arms crossed over abdomen, and coughing to loosen accumulated lung secretions.
  • Take preventive medications as prescribed.
  • There is no need to avoid exercise; however, your doctor may advise you to take preventive medicines before exercising.

When To Call A Doctor

Contact a doctor if you develop symptoms of asthma for the first time. If you have been diagnosed with asthma, call a doctor if your condition is not responding to self-treatment measures or medication—for example, if you develop new symptoms, if the frequency of attacks has increased significantly, or if you need to use a bronchodilator more than six times a day.

Call an ambulance if an attack becomes severe, such as markedly worsened shortness of breath, difficulty speaking, extreme fatigue, or if symptoms do not respond to two doses of a prescribed inhalant.

Reviewed by Allen J. Blaivas, D.O., Division of Pulmonary, Critical Care, and Sleep Medicine, VA New Jersey Health Care System, Clinical Assistant Professor, Rutgers New Jersey Medical School, East Orange, NJ. Review provided by VeriMed Healthcare Network.