What is the primary cause of allergic asthma?

The primary cause of allergic asthma is an IgE-mediated response to allergens. In allergic asthma, the immune system recognizes specific substances—known as allergens, such as pollen, mold, pet dander, or dust mites—as threats. When a susceptible individual is exposed to these allergens, the body produces immunoglobulin E (IgE) antibodies as part of the immune response. These IgE antibodies attach to mast cells and basophils, which, upon re-exposure to the allergen, release inflammatory substances like histamine. This release leads to airway inflammation, bronchoconstriction, and the symptoms associated with asthma, such as wheezing, coughing, and shortness of breath.

This response highlights the role of the immune system in asthma, distinguishing allergic asthma from other forms that may not involve an IgE mechanism. Dust and pollution may contribute to asthma symptoms but are not the direct cause of the allergic response. Similarly, while viral infections and exercising in cold air can trigger asthma symptoms or exacerbate the condition, they do not represent the primary underlying cause of allergic asthma, which is fundamentally an immune response to specific allergens mediated by IgE.