Bronchial hyperreactivity is a condition where the airways in the lungs become overly sensitive to various stimuli, such as allergens, smoke, or cold air. This heightened sensitivity can lead to excessive narrowing of the airways, making it difficult to breathe. It is commonly associated with conditions like asthma and can result in symptoms such as wheezing, coughing, and shortness of breath. The underlying mechanisms involve inflammation and changes in the airway structure, which can be triggered by environmental factors or respiratory infections. Managing bronchial hyperreactivity often includes avoiding known triggers and using medications like bronchodilators or inhaled corticosteroids to reduce inflammation and improve airflow.