Nasal passages are lined with hair and a thin layer of mucus. Sinus cavities contain mucus and tiny hairlike projections called cilia. These components are designed to trap viruses, bacteria and foreign matter. Cilia beat in sequence to propel mucus to the back of your throat, where it is swallowed. Most people are not aware of this, even though the typical person swallows up to a pint of mucus every day.
When you catch a cold, the body's immune system responds to fight the virus. One aspect of this battle is an increased production of mucus. At some point, there is so much mucus in your nasal passages that you can't breathe through your nose.
Expectorants are supposed to thin mucus and make it easier for you to expel it from your body. According to a 2008 Cochrane review, research in adults showed mixed results on whether mucus thinners were effective, and there is no evidence so far to show that they work in children.
Coughing is a protective reflex designed to keep liquid and solid material out of your lungs. Research has shown that cough suppressants in children and adolescents are no better than a placebo. Interestingly, research published last summer found that honey may reduce the coughing that accompanies a cold. Presumably, it works by coating your throat and "calming" the nerve signals that produce the cough. Because there are no significant side effects to honey, it's worth a try. (Honey should never be given to a child younger than 12 months because it could cause infantile botulism.)
Zinc, herbals and vitamin C
Zinc slows replication of some of the viruses that cause colds. In doing so, it can shorten the course and severity of a cold. Research has shown that zinc is effective with adults, but the data are insufficient to recommend its use in children.
There are mixed results concerning the effects of echinacea and vitamin C on cold symptoms in adults. There is no definitive evidence that they help children.
Whenever someone takes medication, it's important to weigh the positive effects against the negative effects. The most common side effects of cold medicine include drowsiness, nausea, abdominal pain, irritability and dizziness. Less commonly, a person may experience tremors, a rapid heart rate and elevated blood pressure. In rare circumstances, convulsions and death have been reported with the use of these medicines, particularly in children younger than 2.
In 2007, the Food and Drug Administration recommended that cold medicines not be used by children younger than 2. At the time, the agency supported the actions taken by many drug companies to voluntarily stop selling cold medicine for this age group. The FDA is reviewing its policy on the use of cold medicine in older children.
What does help?
So what's the parent of a sniffling, congested child with an achy throat to do? Several steps can help make a child more comfortable as his or her body naturally sheds a cold.
Vaporizers and cool-mist humidifiers moisturize the air in a room. They have no direct impact on the symptoms of a cold, but dry air can make a sore throat feel worse. Hot-air vaporizers that create steam should never be used around children because they boil water. If a child knocks over the vaporizer, it could result in a serious burn.
Aromatic vapors have been used to treat colds for centuries, but few studies have been done to assess their effectiveness. A 2010 article in the journal Pediatrics showed an improvement in cough, congestion and sleep difficulty in children treated by applying a vapor rub containing camphor, menthol and eucalyptus to their chests. (More than a third of patients had side effects such as skin redness or a burning sensation of the eyes, skin or nose.) The study has been controversial, in part because the lead author was a paid consultant to a company that makes such a rub.
Saline (salt water) in the form of nose drops, sprays and solutions can also provide temporary relief in some people. There is no evidence that saline washes, which loosen mucus, reduce irritation and lessen dryness, shorten the duration of a cold. Keep in mind, though, that most small children hate having anything put in their noses, and fighting with them to instill drops or sprays could lead to a bloody nose and worse congestion.
No one has proved that drinking lots of fluids loosens mucus or makes a cold resolve more quickly. But it's common sense that keeping a child hydrated will make him feel better. I read a study years ago that showed that among the best fluids is chicken soup, because it loosened nasal mucus in adults. It has never been studied in children, but generations of grandmothers (including my own) have been firm believers in the medicinal value of chicken soup.
So the next time your child has a cold, walk past the cold-medicine aisle at the supermarket and pick up some soup instead.
Howard J. Bennett, a Washington pediatrician, is a regular contributor to KidsPost and an author of numerous books for children. His website, howardjbennett.com, includes a blog on common pediatric problems.