What is Cough?

Cough is a natural reflex that helps protect your throat and airway by pushing germs, dust and mucus away from them. When you cough, air and mucus are propelled out of your mouth at a force of up to 500 miles per hour.

Most coughs are caused by viruses, including colds and flu. Children get croup from viral infections that affect their windpipes.

Causes

The human body’s built-in reflex to cough helps clear the throat of mucus or foreign irritants. The control centers for this reflex are located in the same area of the brain as those that trigger sneezing, swallowing and even yawning. Coughing can also protect against infection by expelling bacteria or viruses that may be contaminating the airways.

While most episodes of cough last a few weeks, a persistent or chronic cough may be a sign of an underlying medical problem that requires further investigation. A cough lasting more than eight weeks or accompanied by fever, chest pain or shortness of breath should be evaluated by a healthcare professional. Other red flags for a cough that requires additional testing or treatment include a wet, dry, scratchy, hoarse or barking cough. This type of cough could be a symptom of pneumonia, tuberculosis or other lung infections.

A cough that occurs only at night, if it persists for more than two weeks or is accompanied by other symptoms such as a tight feeling in the chest, difficulty breathing or a bad taste in the mouth, may be a symptom of gastroesophageal reflux disease (GERD). GERD results from stomach acids that flow backward into the esophagus from the throat. The acid can irritate the lining of the esophagus causing a burning or lump-in-the-throat sensation. This may cause a persistent, dry cough or can worsen during sleep.

Other conditions that can trigger a chronic cough or make an existing one worse include COPD, which is caused by repeated exposure to irritants such as cigarette smoke or dust and can lead to inflammation of the lungs and airways; asthma, which is triggered by allergens such as pollen, pet dander and mold; and interstitial lung diseases, which are characterized by scarring and thickening of the lungs.

Other causes of coughing that require immediate medical attention include a cough that occurs in children and is accompanied by a wheezing sound called stridor; this may be an indication of viral croup or a blockage of the child’s airway from asthma or something else.

Symptoms

The function of a cough is to clear the airways and expel something that doesn’t belong in the lungs or windpipe, such as food, dust or pollen. A cough is the body’s natural defense against such an irritant, and it is typically involuntary. When an infection causes a cough, the irritant triggers the immune system to release phlegm, which helps flush out the invading microorganisms. A persistent, long-lasting cough may be a sign of an illness such as pneumonia or cancer, per the Centers for Disease Control and Prevention (CDC). A cough that produces a greenish or rust-colored phlegm is a classic symptom, as is a fever, chest pain, weakness and fatigue, shortness of breath and wheezing.

A cough that doesn’t produce phlegm is called a dry cough. It’s caused by the chronic dripping of mucus from the throat, usually due to allergies, asthma or gastroesophageal reflux disease (GERD). Certain medications such as those used to treat high blood pressure can also cause dry cough.

If you’re a smoker, persistent coughing can also be a sign of a serious health problem such as emphysema or lung cancer. Inhaling second-hand smoke can irritate the lungs and throat, too. Other health problems that can lead to chronic coughing include rheumatoid arthritis, acid reflux, gastroesophageal reflux disease, chronic obstructive pulmonary disease (COPD), lung infections, sarcoidosis and other disorders of the heart or lungs.

Pregnancy can also cause a cough, but it’s usually only mild and doesn’t last long. However, some women develop a cough that persists after the baby is born. If you’re pregnant and experiencing a prolonged cough, talk to your healthcare provider about it. They can conduct a physical exam, take a blood sample and/or test your phlegm for signs of infection. They may also order X-rays and/or breathing tests to diagnose the problem. In some cases, the healthcare provider might refer you to a specialist for further evaluation and testing. If you have a viral infection, your healthcare provider will prescribe medicine to treat it. Other times, your healthcare provider will simply ask you to relax and rest until the symptoms go away.

Treatment

Many coughs are caused by common viruses and will go away on their own with time. But some lingering or chronic coughs may require treatment of the underlying cause. If you have asthma or acid reflux disease, your doctor can prescribe medicines to treat the underlying problem and help with the cough. People who smoke should quit smoking to reduce the inflammation in their lungs that can lead to a persistent cough. If you are taking medications for another condition, your doctor will check how well the medicine is working and change your dosage if needed.

The best way to treat a cough is to identify the cause and get rid of it. A careful history and physical examination can help you find the cause. For example, your doctor will look in your nose and throat for signs of inflammation. He or she will also listen to your chest and lungs for sounds of wheezing and difficulty breathing.

In most cases, cough due to a viral infection will improve without medication and usually goes away within one to two weeks as the virus clears your body. But some patients do not find satisfactory relief with over-the-counter (OTC) medications that suppress the cough. A Cochrane review indicates that anti-tussives have only a limited efficacy in acute cough.

Your doctor may recommend over-the-counter medications, such as decongestants, antihistamines, or mucus thinners, to relieve your symptoms. Your doctor might also prescribe an antibiotic if the cause is an infection. Medications called angiotensin converting enzyme inhibitors, which are used to control high blood pressure, can cause a chronic cough in up to 20 percent of patients who take them. Switching to a different type of medication may improve the cough over a few weeks in these patients.

If you have a long-lasting or chronic cough, your doctor may order tests to diagnose the underlying cause. A chest x-ray and a lung function test, which checks for abnormalities in the movement of air, may be required. A sputum sample is sometimes collected to detect the presence of a fungal or bacterial infection.

Prevention

Coughing is your body’s way of removing irritants from your throat and airways. It starts when an irritant stimulates nerves that send a message to the brain; the cough reflex then forces the irritant out of your airways and down the throat. Some medical conditions, like asthma or chronic obstructive pulmonary disease (COPD), cause the airways to narrow and obstruct airflow in and out of the lungs, causing you to cough.

Keeping your immune system healthy can help prevent some illnesses that can cause cough, such as the common cold or flu. Exercise, getting enough sleep, and eating a variety of foods rich in nutrients can all support a strong immune system. Wash your hands frequently, especially after coughing or sneezing. Avoid contact with people who are sick, and stay away from smoke or vapors from cigarette and cigar smoke.

If you have a respiratory infection that causes a cough, try taking cough suppressant medicine to reduce the urge to cough. Honey is also a popular home remedy for coughs. It has been shown to help children sleep better and decrease how often they cough at night. However, don’t give honey to babies under 4 years of age because they are more likely to develop a bacterial infection from it.

Avoid allergens that may trigger your allergies and a cough, such as dust or pet dander. Use a humidifier in your bedroom or run a cool mist one when you suffer from a dry cough, and consider adding saline nasal rinses to your treatment regimen. To help relieve a wet cough, eat food containing probiotics, such as yogurt with live cultures and sauerkraut, or take a supplement that contains Lactobacillus. You can find probiotics in a variety of foods, including some cheeses and pickles, and many health stores carry them in pill form. Talk to your doctor about whether these supplements are right for you. If you have a chronic condition that triggers cough, such as acid reflux or asthma, talk to your doctor about ways to treat it and manage the symptoms.

Treatment for other diseases also available