Coughing is one of the most common reasons people seek outpatient treatment, accounting for some 30 million visits to doctors’ offices a year in the U.S. Everyone coughs sometimes; it’s one of the body’s most valuable defense mechanisms—an involuntary reflex that protects your lungs from foreign or undesirable substances, whether it’s a piece of food that “went down the wrong way” or a microscopic pollen grain that you inhaled and to which you are allergic. But when coughing moves from episodic to ongoing, it can become a problem—interrupting your sleep, causing discomfort and aggravation, and potentially injuring your throat or other body systems. Ongoing coughing can also indicate an underlying problem that needs treatment.
Here are answers to questions you may have about coughing. Some of the answers may surprise you.
1. Is there a gender difference in coughing?
Yes. Women not only are more likely to seek medical attention for a long-term (chronic) cough, but they also are more likely than men to have a dry (that is, unproductive) cough, to cough at night, and to cough more frequently. Researchers believe this may be in part because women have a more sensitive cough reflex compared with men.
2. What’s the difference between acute and chronic coughing?
A person who has been coughing for less than three weeks is said to have an acute cough, most likely as a result of an acute viral respiratory tract infection, allergies, or pneumonia. Coughing that continues for three to eight weeks or longer is called either subacute or chronic. Such coughs are commonly associated with asthma, gastroesophageal reflux disease (GERD), postnasal drip, or sinusitis; they could also be due to lingering irritation or inflammation in the airway as a result of an upper respiratory infection, or stem from other causes.
In the vast majority of cases, a physician can find a cause for a chronic cough. But sometimes a person may have a cough for years with no known cause. In these cases, an over-sensitive cough reflexmay be the culprit. Treatment may include the prescription medication lidocaine, an anesthetic used off-label for chronic coughs and administered in an inhalable mist, referred to as nebulized lidocaine.
3. What causes coughing at night?
Several situations or conditions can produce nighttime activation of the cough reflex, which is normally suppressed while you’re sleeping. This is called, fittingly, nocturnal coughing. A nighttime dry cough is often associated with being exposed to air pollutants, such as tobacco smoke or ozone. Asthma can also cause nighttime coughing, as can upper respiratory infections, with their characteristic postnasal drip. About 20 percent of people who take the popular hypertension medications known as angiotensin-converting enzyme (ACE) inhibitors experience a chronic cough that gets worse at night. If you’re among them, your pharmacist or physician might suggest switching to another type of hypertension drug, such as a calcium channel blocker.
4. Can coughing cause injuries or other complications?
Yes. Because of the high pressure that builds up in the chest when a cough is initiated, and the rapid velocity with which the air is expelled (up to 500 miles per hour!), a person can experience complications or injuries from coughing. Those include headaches, dizziness, urinary incontinence, and even rib fractures. The latter are most likely to occur in women who have low bone mineral density, but they can happen in anyone.
5. Can menthol or honey help a cough?
They might. Inhaling vaporized air that contains menthol may ease coughingby reducing sensitivity to the coughing stimulus, according to astudypublished in 2012 in Pulmonary Pharmacology and Therapeutics. And there’s evidence that Vicks Vapo-Rub, which is applied topically to the chest and contains a chemical relative of menthol, levomenthol—as well as camphor, eucalyptus, and turpentine oils—reduces nighttime coughing, congestion, and difficulty sleeping better than a control (petrolatum, such as Vaseline) in children ages two to 11. (We couldn’t find any evidence on Vicks in adults.)
Honey may also relieve a cough, though the evidence is limited. A study published in 2012 in Pediatrics involved several hundred young children (ages one to five years) who had an upper respiratory infection with a nighttime cough. The children were given one of three different types of honey (eucalyptus, citrus, or labiatae, an aromatic herb honey) or a placebo (date extract) half an hour before bedtime. The parents evaluated their children, finding that the honeys were better than the control at reducing cough frequency and severity, though both groups improved. The authors hypothesized that the sweetness of the honey (and the control substance) could affect the cough reflex. But that wouldn’t explain why the honeys did a better job than the control. In addition, a small Italian studypublished in 2015 found that giving children two teaspoons of honey with milk before bedtime quelled some coughs just as well as two common cough medicines. (Children younger than a year old shouldn’t be given honey because of the risk of infant botulism.)
6. How about cough medicines—are they effective?
It’s complicated and depends on many things, including the type of medication, whether it’s over-the-counter (OTC) or prescription, whether the cough is acute or chronic, and the reason for the cough, as well as individual variations in people’s cough reflex sensitivity and how they respond to cough medication.
Cough preparations, whether OTC or prescription, can be divided into two categories: antitussives (also called suppressants), which suppress a cough, and expectorants, which loosen it. Suppressants are generally used for dry coughs, and expectorants for productive coughs (those bringing up phlegm). Commonly used suppressant ingredients include dextromethorphan, which is available in numerous OTC cough syrups, and benzonatate (Tessalon), which requires a prescription. If those don’t help, cough syrups containing the opioid codeine can be effective, but they also have more potential side effects. For unexplained chronic coughs, the anti-seizure medication gabapentin (Neurontin) is sometimes prescribed off-label as a cough suppressant.
For a productive cough—meaning it is bringing up phlegm—a suppressant isn’t recommended, since productive coughs help to clear the airway. In those cases, an expectorant that can make the phlegm less viscous and, therefore, easier to expel, may be helpful, at least in theory. A common OTC expectorant ingredient is guaifenesin.
But there’s a big problem with OTC cough syrups of both kinds: There’s no good evidence that they work any better than a placebo. In a review published in 2014 in the Cochrane Database of Systematic Reviews, for example, researchers examined 29 randomized controlled studies of different OTC cough preparations involving almost 5,000 adults and children. They found no good evidence for or against their use for acute cough. (The authors noted that many of the trials were small, were quite different from each other, involved the support of drug companies, or were of poor quality.)
In another paper, published in 2016 in BMJ Open Respiratory Research, the researchers reviewed the evidence on antitussive (suppressant) drugs used in Europe for acute coughs stemming from the common cold. They concluded that many of the studies had methodological problems that made it difficult to determine if people with an acute cough derived any benefit from using these products, in part because most acute coughs eventually abate on their own. And any soothing effect the syrups do have may be due simply to their texture. The researchers suggest that making a cup of hot water with honey and lemon at home may be just as good an option.
The benefit of OTC cough syrups is especially questionable in children, for whom the products are also more risky.The FDA has warned parents not to give such drugs to children under age two because serious side effects can occur; the drugs’ labels say they shouldn’t be used in children under four. Safer alternatives include honey (see above), agave nectar, and grape-flavored water.In astudypublished in 2014 inJAMA Pediatrics, researchers found that children under four who were given a teaspoon of agave nectar or grape-flavored water at bedtime had greater improvements in cough-related symptoms than those who got no treatment.
7. What about using a humidifier?
It may be worth trying. Cold dry air dries mucus, making it harder to clear from your nasal passages. Moist air helps loosen it. So it makes sense that a humidifier may ease symptoms of a cold, sore throat, or cough—though there’s no actual evidence that using a humidifier reduces coughing. Whether proper humidity can help prevent colds and other conditions that cause coughing is hard to say. Some experts think that dry air irritates nasal passages, making you more susceptible to colds. People with asthma often find it more difficult to breathe dry cold air. On the other hand, very high humidity (over 60 percent) can provide a good environment for viruses and bacteria. And it promotes the growth of mold, which can cause allergies in sensitive people. For tips on safely choosing and using a humidifier (including cleaning advice), see Humidifiers: Helpful or Harmful?
8. When should you seek medical attention for a cough?
If you’ve been treating your cough at home but you find it getting worse or lasting more than a week or so, you should call your physician’s office. Other signs or symptoms that warrant seeking medical care include having difficulty breathing, wheezing when you cough, experiencing chest pain or a fever, coughing up blood or thick yellow or green mucus, having night sweats, or losing weight without intending to.