Asthma is a medical condition of chronic lung inflammation. It's characterized by episodes of worsening symptoms, or exacerbations, triggered by pollen, upper respiratory infections, exercise and changes in the weather, among other factors. Dry cough and respiratory distress with wheezing, rapid breathing and retractions are symptoms of asthma in children.
Significance
According to the Merck Manual for Healthcare Professionals, asthma is one of the most common chronic conditions of childhood, affecting more than six million children in the United States and between 4 percent and 7 percent of the population worldwide. Despite recent medical advances in treatment and prevention, it's a significant cause of school absenteeism in children.
Function
According to the National Lung Health Education Program, cough is a defense mechanism that helps clear the airways. It also prevents pollen, smoke and other irritants to accumulate and helps avoid infection of the lungs by bacteria and viruses.
Features
Asthma causes inflammation around the airways, constricting their diameter and making it difficult to exchange air in the lungs. As air tries to move through the narrowed airway passages, it emits a high-pitched, whistling sound called wheezing. Dry cough results from airway irritation due to inflammation and to the increase in mucus and other cellular debris that accumulate in the airways.
Considerations
Other causes of dry cough in children with asthma include allergies, and sinus and other upper respiratory infections. Allergies to pollen, pet dander and other substances are triggers for asthma exacerbations. According to the Asthma and Allergy Foundation of America, these allergens increase the secretion of IgE, a protein in the body that initiates the allergic reaction. It causes an increase in histamine, a substance that causes the symptoms of allergies--including the dry cough. Upper respiratory infections produce mucus and phlegm, which drains in the back of the throat. The dry cough is a mechanism to clear this mucus from the upper airway.
Warning
Another common cause of dry cough in children with asthma is gastroesophageal reflux disease, or GERD. Children with GERD have an abnormal flow of stomach acid back into the esophagus. This acid reflux can go all the way up in to the airway, irritating the throat and producing a dry cough. The child can also aspirate the acid into the lungs, triggering an asthma attack.
