Asthma symptoms and triggers, Symptoms of asthma include wheezing and coughing, tightness of the chest, and shortness of breath. Having asthma means you have sensitive airways that are reactive to specific triggers. These include triggers that cause an allergic reaction, such as pollen, dust, or mould, and this type of asthma is called allergic asthma. Non-allergic asthma triggers include irritants like inhaled chemicals, cigarette smoke, cold air, an infection, stress, exercise, or some medications. Exercise-induced asthma is a particular type of asthma that only happens after exertion but can last for over an hour after you stop exercising. Eventually, exposure to an asthma trigger causes inflammation of the sensitive bronchiole linings so that they become swollen and inflamed. Another sign of inflammation of the airways is the overproduction of mucus, usually produced to keep the airways moist, and this further blocks the airways. Bronchioles are lined by bands of smooth muscle that are usually relaxed, allowing the bronchioles to expand and air to pass freely through into the air sacs or alveoli of the lungs. When the airways are inflamed, the smooth muscle contracts, which narrows the bronchioles making breathing more difficult. As the airways narrow, it becomes harder to inhale and requires more effort to blow air out of the lungs. This narrowing of the bronchioles is called bronchospasm. If the bronchioles are already in a state of chronic inflammation, an asthma trigger may cause sudden constriction and narrowing of the bronchioles, which can cause an asthma attack. |