Asthma is a chronic disease marked by periodic attacks of coughing, wheezing and difficulty breathing, especially inhaling. During an asthma attack, the air passages in the lungs become narrow or blocked by mucus or a muscle spasm. Asthma attacks can be triggered by allergens such as pollen, animal dander, molds, fungi, certain foods, and house dust. Irritants such as tobacco smoke, smog, exhaust fumes, household cleansers, and other chemicals may also cause asthma attacks. Even sudden changes in temperature or humidity, strong winds, and strenuous exercise may trigger attacks. Allergy testing can be helpful in pinpointing the exact cause. Asthma treatment begins by identifying and avoiding the factors that cause the attacks. In most cases, an attack can be controlled by using an inhaler, which produces a fine mist that is inhaled directly into the bronchial tubes. Severe attacks may need to be treated by medication that relaxes the bronchial muscles. For more information about asthma, contact your healthcare provider.