Asthma is a condition in which your airways narrow and swell and may produce extra mucus. This can make breathing difficult and trigger coughing, a whistling sound (wheezing) when you breathe out and shortness of breath.

For some people, asthma is a minor nuisance. For others, it can be a major problem that interferes with daily activities and may lead to a life-threatening asthma attack.

Asthma can't be cured, but its symptoms can be controlled. Because asthma often changes over time, it's important that you work with your doctor to track your signs and symptoms and adjust your treatment as needed.

Symptoms

Asthma symptoms vary from person to person. You may have infrequent asthma attacks, have symptoms only at certain times — such as when exercising — or have symptoms all the time.

Asthma signs and symptoms include:

• Shortness of breath
• Chest tightness or pain
• Wheezing when exhaling, which is a common sign of asthma in children
• Trouble sleeping caused by shortness of breath, coughing or wheezing
• Coughing or wheezing attacks that are worsened by a respiratory virus, such as a cold or the flu

Signs that your asthma is probably worsening include:

• Asthma signs and symptoms that are more frequent and bothersome
• Increasing difficulty breathing, as measured with a device used to check how well your lungs are working (peak flow meter)
• The need to use a quick-relief inhaler more often

For some people, asthma signs and symptoms flare up in certain situations:

• Exercise-induced asthma, which may be worse when the air is cold and dry
• Occupational asthma, triggered by workplace irritants such as chemical fumes, gases or dust
• Allergy-induced asthma, triggered by airborne substances, such as pollen, mold spores, cockroach waste, or particles of skin and dried saliva shed by pets (pet dander)