Asthma is a chronic disease that affects more than 150 million people worldwide and is characterized by breathing difficulty caused by tightening and swelling of the bronchial tubes in the lungs, tightness in the chest and fits of coughing, according to the University of Maryland Medical Center. In many cases coughing may be the only symptom, and the individual may not be aware that he has asthma. Coughing is a natural mechanism to expel foreign objects from the airways. In asthmatics, coughing is usually dry, which means that nothing is expelled.
Inflammation and Swelling
Asthma is an inflammatory disease that can be triggered by allergens that cause the immune system to overreact. The University of Maryland Medical Center explains that an immediate response to an allergen or other trigger, such as cold air, causes swelling and narrowing of the lungs. This is followed by further inflammation of the airways in the lungs, which obstructs breathing. The swelling and inflammation cause coughing as breathing becomes difficult.
Mucus and Infection
People with asthma are often more susceptible to lung infections, according to the Asthma Society of Canada. Reactions to allergens cause inflammation that results in the accumulation of mucus or fluid in the airways of the lungs. This worsens coughing in asthmatics. The fluid also increases the risk of infections such as influenza, which in turn exacerbates the coughing. It makes breathing difficult, and chronic coughing occurs in response to the lung irritation.
Chest Tightness and Muscle Spasms
Asthma also causes the smooth muscle lining of the lungs to contract or spasm and the muscles that surround the lungs to tighten. This symptom is often experienced by asthmatics as a weight, pressure or crushing sensation in the chest and can be very frightening. The tightness of the air passageways makes breathing difficult and painful, triggering coughing to clear the lungs.
