A cough is one of the most common reasons that people see a doctor. Coughing is an important reflex that keeps lungs and airways free of secretions or foreign objects that might interfere with breathing. Coughing can be a response to an irritation or obstruction in the throat, larynx, bronchial tubes, or lungs, but in most cases a cough doesn't require medical attention.
Your lungs, sinuses, and throat contain a network of cough receptors—nerve endings that transmit cough messages to the brain. Basically, a cough begins with a deep inhalation of air and closing of the epiglottis and vocal cords, which keeps the air in the lungs. Your diaphragm and chest muscles contract, creating pressure. The epiglottis and vocal cords open abruptly, so that the trapped air bursts out of the lungs, loosening and expelling foreign objects and mucus.
You may not notice it, but people normally cough once or twice an hour—an action that clears the throat. That’s all well and good, until you get the dry hacking type of cough that keeps you awake at night and turns into a social liability by day.
There are two distinct types of coughs, productive and nonproductive. A productive cough brings up sputum from the respiratory tract; this process helps speed recovery from inflammation of the airways and lungs. A nonproductive cough is dry and scratchy, raises no sputum, and is typically a response to allergies or medication.
When you have a cold, a cough is usually dry during the first stages; later you may have a productive cough, which usually means that your cold is on the way out.
Symptoms of Coughs
A cough is a symptom itself rather than an ailment, and coughs can have a number of different patterns and causes, as described below. The production of mucus, phlegm, or blood can indicate an infection. The mucus may be thin or thick in consistency, clear, green, yellow, white, or blood-stained.
Other symptoms that may be associated with cough include runny nose, headache, muscle aches and sore throat.
What Causes Coughs?
Along with colds, flu is a common cause of coughing that can last for several days. Other respiratory tract conditions associated with coughing include asthma, which produces mucus and triggers a productive cough, and bronchitis. It may also be associated with other chronic diseases, such as cystic fibrosis and emphysema. One of the leading causes of chronic coughing is cigarette smoking because it increases the production of mucus in the bronchial tubes, which then has to be moved out by coughing.
Coughing can also be triggered by dust, an object or piece of food trapped in the airways, and pollution or other environmental irritants (including second-hand smoke from cigars and cigarettes, dust, or smog).
Gastroesophageal reflux (heartburn) can also cause paroxysms of coughing. And certain medications can produce coughing bouts. For example, many people who take ACE inhibitors—a type of drug for treating high blood pressure—develop a dry cough.
Coughing, especially when accompanied by chest pain or breathing difficulty, can indicate a more serious medical condition, such as pneumonia, lung cancer, cancer of the larynx, congestive heart failure, or some other severe problem.
What If You Do Nothing?
A cough will generally subside on its own. However, a persistent cough is a telling symptom for a number of serious diseases. If a cough continues for more than five days without any obvious reason or if it interferes with your everyday activities, contact your physician.
Home Remedies for Coughs
The following remedies should help make a common cough more bearable and shorten its duration.
- Drink plenty of water. Water is the best expectorant because it helps thin secretions and makes them easier to bring up. For most coughs, water is often more effective than medications.
- Loosen up with an expectorant. If you’re congested but your cough is not productive, you may wish you had something to loosen up the mucus. Plenty of products, known as expectorants, claim to do just that. All contain guaifenesin, the only expectorant approved by the Food and Drug Administration (FDA), which has classified it as “safe and effective.” You should know, however, that guaifenesin has never been proved effective in clinical trials, nor has the necessary dosage been established. There is also no standard amount of this ingredient in cough medicines.
- Suppress a dry, hacking cough. The most common kind of single-ingredient cough medicine is a suppressant, which acts on the cough center in the brain. Some suppressants contain the narcotic drug codeine or a codeine derivative, which are approved for over-the-counter sales in several states. Codeine is effective, but can cause stomach upset and constipation. A better choice is a suppressant with dextromethorphan, a synthetic relative of codeine that works on the same nerve center to suppress coughing but with much milder side effects. A third type is one containing diphenhydramine (such as Benadryl), the only antihistamine recommended for treating coughs. Like codeine, it may make you drowsy. If you decide to use a cough medicine, remember that generics are as effective as the comparable brand-name product and usually a lot less expensive.
- Steer clear of combinations. Be cautious about combinations of ingredients. If your cough is allergic in origin, an antihistamine can help, but you probably won’t also need an expectorant. Antihistamines dry up secretions, and expectorants are supposed to loosen them, so if you combine these two ingredients, you are working against yourself. And combinations of ingredients may not have sufficient doses of any one of them.
- Read and follow warning labels on all cough medicines. Some cause drowsiness and should not be taken if you’re driving; some can interact with other medications. If you’re pregnant or giving cough medicines to children, it’s a good idea to get professional advice.
- Try cough drops—or hard candy. Despite the medicinal taste and smell of some of the more serious-looking cough drops and throat lozenges, there’s no clinical evidence that they’re better than hard candy. Eucalyptus and menthol oils, topical anesthetics, and other ingredients may not help you any more than a plain old lemon drop. Sucking on a hard candy (or cough drop) probably works by promoting saliva flow, which is soothing; the sugar can also soothe the throat. Cough drops are generally harmless, but aromatic oils can irritate mucous membranes or upset your stomach. Like hard candies, cough drops that contain sugar can contribute to tooth decay.
- Try a vaporizer. If your home is dry and overheated, use a vaporizer in your room to add moisture to the dry air. This is especially important at night when you sleep. The humidified air helps liquefy the mucus and make your cough more productive. Since vaporizers can harbor bacteria and fungi that can aggravate and even cause a cough, be sure to clean your machine regularly.
- Don’t forget ointments and salves. Camphor ointments (such as Vapo Rub) also help ease coughing and are the only topical treatment approved by the FDA. In addition, rubbing your chest with menthol salves or pure peppermint oil and breathing the vapors may also help quell coughing.
- If you smoke, quit. Smoking poisons the breathing tubes, and the chronic cough that results from smoking—the so-called smoker’s cough—is often a precursor of fatal diseases, such as lung cancer.
- If your cough is due to heartburn, treat the heartburn. If you have persistent heartburn along with a cough, stopping the heartburn may clear up your cough.
- Gargle with warm water. Gargling with warm water and salt several times a day can help clear phlegm from the throat.
Avoid tobacco smoke. Coughing may result from exposure to cigarette smoke. Encourage your spouse, family members, or co-workers to quit smoking.
Reduce exposure to irritants. If you are regularly exposed to dust, chemicals, or smoke at work, be sure that you wear a mask and that your work area is properly ventilated.
Avoid air pollution. If you exercise outdoors, be sure to exercise early in the day. In most major cities, air pollution levels are lowest during the early morning hours, until about 10 A.M.
Consider air filters. An air conditioner or special air filter can be useful, especially if you have seasonal allergies or asthma.
Beyond Home Remedies: When To Call Your Doctor
If coughing brings up mucus that is yellow, brown, or green, it may indicate infection that needs to be treated by your physician. If the mucus is blood-tinged or bright red in color, contact your physician immediately. Excessive coughing can cause blood vessels in the throat to rupture and bleed, which is not a serious problem. However, you may have an acute respiratory ailment that causes bleeding, and this needs to be treated immediately.
Also contact your doctor if you are coughing frequently for more than five days or for no obvious reason, or you have a cough attributable to a cold, flu, or some other known cause that fails to get better within three weeks.
You should also call your doctor if coughing is accompanied by a fever, skin rash, thick sputum, an earache, chest pain, shortness of breath, lethargy, or pain in the teeth or sinuses.
What Your Doctor Will Do
After taking a medical history, the doctor may x-ray your chest and sinuses, take a culture of your sputum, and prescribe medication. If it’s warranted, you may be sent to a medical specialist to treat the underlying illness causing your cough.
The Complete Home Wellness Handbook
John Edward Swartzberg, M.D., F.A.C.P., Sheldon Margen, M.D., and the editors of the UC Berkeley Wellness Letter
Updated by Remedy Health Media