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.

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)
    • Dust
    • Changes in weather (most often cold weather)
    • Chemicals in the air or in food
    • Exercise
    • Mold
    • Pollen
    • Respiratory infections, such as the common cold
    • Strong emotions (stress)
    • Tobacco smoke

  Aspirin 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.

Symptoms

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) production
• Pulling 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 between
  • May be worse at night or in early morning
  • May go away on its own
  • Gets better when using drugs that open the airways (bronchodilators)
  • Gets worse when breathing in cold air
  • Gets worse with exercise
  • Gets worse with heartburn (reflux)
  • Usually begins suddenly

Emergency symptoms:

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

Other symptoms that may occur with this disease:

• Abnormal breathing pattern –breathing out takes more than twice as long as breathing in
• Breathing temporarily stops
• Chest pain
• Tightness in the chest