There are many causes of bronchial asthma, including infectious factors, allergic factors, and physical and chemical factors. 1. Infectious factors: respiratory viral infections are associated with the formation and attack of asthma, the most common being rhinovirus. 2. Allergic factors: patients with bronchial asthma may be caused by allergies. Common allergens include mites, willow wool, dust, animal hair, pollen, etc. 3. Physical and chemical factors: Bronchial asthma may also be triggered if the lungs are irritated when exposed to specific physical and chemical factors such as paint and tobacco. Bronchial asthma is also closely related to heredity, airway hyperresponsiveness, etc. Patients suspected of having bronchial asthma should go to the hospital for examination and treatment in time so that their condition can be controlled. Patients try to avoid the above triggers in daily life, pay attention to good personal protection, pay attention to maintain a happy mood.