The following table presents a classification guide to the severity of asthma, hosted by the National Heart, Lung and Blood Institute :
| ||Symptoms||Symptoms Night||Pulmonary Function|
|STEP 1 |
|Less than once a week. Asymptomatic between attacks.||Twice a month or less.||FEM and / or FEV1> 80% predicted. Variability <20%.|
|STEP 2 |
|More than once a week but not daily ||More than twice a month but not every week. ||FEM and / or FEV1> 80% predicted. Variability 20-30%.|
|STEP 3 |
|Every day. The symptoms affect normal daily activity.||Every week at least one night.||FEM and / or FEV1 60-80% predicted. Variability> 30%.|
|STEP 4 |
|Continued symptoms.||Daily||FEM and / or FEV1 <60% predicted. Variability> 30%.|
Classification of Asthma in terms of age
- Asthma in infants . The vast majority are of viral origin, by the same viruses that cause bronchiolitis. In this type of asthma can not be demonstrated eosinophilic infiltration of the mucosa, so that if asthma is not by definition.
- Asma school age . It mainly affects boys (2:1 to 4:1, depending on age groups), and is associated with allergy to pneumoallergens in most cases.
- Asthma in adolescence . It is characterized by the denial of symptoms and treatment regimens, and is the age range with higher mortality.
- Adult asthma .