When the breathing passages become irritated or infected, an attack is triggered. The attack may come on suddenly or slowly over several days or hours.
The main symptoms that signal an attack are as follows:
Symptoms may occur during the day or at night. If they happen at night, they may disturb your sleep.
Wheezing is the most common symptom of an asthma attack.
Wheezing is a musical, whistling, or hissing sound with breathing.
Wheezes are most often heard during exhalation, but they can occur during breathing in (inhaling).
Not all asthmatics wheeze, and not all people who wheeze are asthmatics.
Current guidelines for the care of people with asthma include classifying the severity of asthma symptoms, as follows:
Mild intermittent - Includes attacks no more than twice a week and nighttime attacks no more than twice a month. Attacks last no more than a few hours to days. Severity of attacks varies, but there are no symptoms between attacks.
Mild persistent - Includes attacks more than twice a week but not every day, and nighttime symptoms more than twice a month. Attacks are sometimes severe enough to interrupt regular activities.
Moderate persistent - Includes daily attacks and nighttime symptoms more than once a week. More severe attacks occur at least twice a week and may last days. Attacks require daily use of quick-relief (rescue) medication and changes in daily activities.
Severe persistent - Includes frequent severe attacks, continual daytime symptoms, and frequent nighttime symptoms. Symptoms require limits on daily activities.
Just because a person has mild or moderate asthma does not mean that he or she cannot have a severe attack. The severity of asthma can change over time, either for better or for worse.