Asthma is characterized by airway obstruction and inflammation that is at least partially reversible with medication. Asthma symptoms may be triggered by a variety of mechanisms. Symptoms of asthma include coughing, wheezing, shortness of breath or rapid breathing, and chest tightness.
Allergic asthma, also called extrinsic asthma, is a type of asthma where symptoms are triggered by inhaling allergens such as dust mites, pet dander, pollens, and mold. For some people, these allergens induce inflammation in the lungs that can lead to worsening asthma symptoms.
Non-allergic asthma, also called intrinsic asthma, is a type of asthma where symptoms are triggered by other factors such as anxiety, stress, exercise, cold air, dry air, hyperventilation, smoke, viruses, or other irritants. These non-allergic triggers can also cause worsening asthma symptoms in patients with allergic asthma. Non-allergic asthma is more common in adults and often occurs in patients who develop asthma after the age of 40.