With intermittent asthma there are only occasional episodes of wheezing or coughing (less than once a month). Most children with asthma only have intermittent asthma. The symptoms of intermittent asthma are usually easily controlled and do not affect the quality of life.
With persistent asthma the episodes are more frequent (at least once a month). Persistent asthma may be:
- Mild: Episodes of coughing or wheezing occur once or twice a week
- Moderate: Episodes of coughing or wheezing at least 4 times a week
- Severe: They have daily symptoms which interfere with sleep and schooling
With intermittent or mild persistent asthma the peak expiratory flow is usually 80% or more of predicted. This falls to 60–80% with moderate and less than 60% with severe asthma.