Definition

Asthma is an inflammatory disorder of the airways, which causes attacks of 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 swell. This reduces the amount of air that can pass by, and can lead to wheezing sounds.
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 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).
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 an individual or family history of allergies, such as hay fever (allergic rhinitis) or eczema. Others have no history of allergies.

Symptoms

• 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
  • Comes in episodes
  • 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

Additional symptoms that may be associated with this disease:

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