According to the Global Initiative for Asthma (GINA), asthma is a respiratory disease that can be diagnosed by a history of characteristic respiratory symptoms such as wheezing, shortness of breath, tightness of chest and a cough that varies in intensity over time, along with variable expiratory airflow limitation. Asthma is usually associated with a respiratory response to direct and indirect stimuli such as exercise, exposure to allergens, irritants, weather changes or viral respiratory infections and a chronic inflammatory process in both the small and larger airways. Symptoms and airflow limitation may vary in time and intensity and may disappear with adequate treatment. During physical examination, the degree of dyspnea is evaluated and attention is paid to a possible wheeze and prolonged expiration. Variability in airflow limitation can be demonstrated by spirometry and forms an important condition for diagnosing asthma. Airflow limitation shows reversibility, i.e. an FEV1 increase of >12% and 200 ml after using a bronchodilator during one visit, or variability, i.e. an increase in FEV1 >12% and 200 ml between two visits.
Asthma is called a heterogeneous disease because it has several different phenotypes, i.e. clusters of clinical and / or pathophysiological features, which may require different treatment strategies. The most common phenotype is allergic asthma, which is often diagnosed in childhood. Allergic asthma is characterised by eosinophilic airway inflammation and responds well to treatment with inhaled corticosteroids. In non-allergic phenotypes of asthma, symptoms and airflow limitation are not caused by allergens but by other stimuli, such as (eosinophilic) inflammation (which may often present in combination with nasal polyps), exercise induced asthma, late-onset asthma or asthma with obesity. In case of phenotypes with only little eosinophilic inflammation (such as asthma with obesity) patients may have a limited response to inhaled corticosteroids. Patients with long-standing asthma may develop a persistent airflow limitation, most likely due to airway remodelling. Asthma is usually diagnosed by the GP and managed in primary care.
Treatment is aimed at achieving good asthma control, tailored to personal treatment goals. In other words, as few symptoms and as few exacerbations as possible, no restrictions in activities, and normal participation in social life. Not smoking and having a smokefree environment are important measures against asthma. Inhaled medication is the basis of medication therapy and this includes inhaled corticosteroids (ICS) in most asthma phenotypes, which may or may not be combined with long-acting beta-2 agonists (LABA). With good asthma control in adults, the use of short-acting beta-2 agonists (SABA) is not usually necessary. SABA use is advised in children with frequent symptoms (and in children under six years of age with episodic expiratory wheezing but for who ‘asthma’ is usually not yet definitively diagnosed). LABA use in children with asthma, if necessary, is usually prescribed by a paediatrician or (paediatric) pulmonologist.