Coughing is a reflex mechanism triggered by inhaled irritants or mucus stimulating nerves in the respiratory tract. Many conditions and diseases produce a cough as a symptom, making cough one of the most common reasons people seek medical care, notes MayoClinic.com. Chronic cough, according to the University of Maryland Medical Center, is defined as a cough that lasts longer than four weeks. Treatment of chronic cough depends on the underlying condition.
Antihistamines
Allergies, which occur when the immune system reacts abnormally to harmless substances such as pollen and dust, cause swelling of the nasal passages and increase the production of mucus. Although people normally swallow mucus unconsciously, excessive mucus can accumulate in the back of the throat and drip into the respiratory tract, triggering a cough.
Antihistamines are a type of medication that works by preventing histamine—a chemical released during an allergic reaction that stimulates the mucus secretions—from attaching to cells. First-generation antihistamines, which include brompheniramine, chlorpheniramine and diphenhydramine, are the most effective at treating coughs, according to MayoClinic.com. Because these medications cause drowsiness, difficulty concentrating, dry mouth and headaches, doctors and patients often prefer to take second-generation antihistamines, such as loratadine and cetirizine.
Cough Suppressants
Cough suppressant medications, also known as antitussive agents, relieve cough by relaxing the airways and blocking the coughing reflex. The medication dextromethorphan is a cough suppressant available in many over-the-counter medications. Cough suppressants should not be used to treat coughs caused by an increase in mucus in the airways, according to the University of Iowa. Treating chronic coughs triggered by mucus requires removing the mucus, and suppressing the cough fails to accomplish this.
Although cough suppressants can temporarily relieve the cough, in the case of chronic coughs, they fail to treat any underlying cause; therefore, the cough will usually return.
Inhaled Corticosteroids
Asthma, a chronic condition that causes inflammation and narrowing of the airways, can cause a chronic cough. Although no cure exists for asthma, a condition that affects nearly 22 million people in the United States, treatment focuses on controlling the symptoms, as described by the National Heart Lung and Blood Institute. Another cause of chronic cough is chronic obstructive pulmonary disease, known as COPD, which occurs when the airways become thick and inflamed because of chronic bronchitis or emphysema.
Inhaled corticosteroids can provide long-term control of both asthma and COPD symptoms. Taken daily, inhaled corticosteroids reduce the inflammation in the airways, which decreases their sensitivity to inhaled substances. Although inhaled corticosteroids don't provide immediate relief, over time they reduce the frequency and severity of symptoms such as cough.
