o you know why we have sinuses? Don’t feel bad if you don’t. The experts also are puzzled about why we have four pairs of empty, air-filled cavities in the face, and why they cause so many problems.

But doctors do know how sinuses function. Lined by the same type of mucous membranes that coat the back of your throat, your sinuses take in air and drain out mucus containing germs and debris. Children often are plagued by sinus problems. Factors that affect your child’s sinuses include:

Allergies
Family history
Infection
Pollution
Second-hand smoke

These problems may contribute to each other. For instance, a child is more likely to develop sinus trouble if one or both parents tend to be congested, explains Dr. Vanthaya Gan, a pediatrician on staff at Children’s Medical Center of Dallas. “If a child is prone to allergies, being around second-hand smoke will worsen the condition.”

Exposure to allergens and second-hand smoke can make your child more susceptible to sinusitis, an inflammation and infection that can cause pain and swelling on the side of the face, the bridge of the nose and under the eyes. Look for a fever of over 101 degrees; thick, colored discharge; fatigue; or a cold that is not getting better after 10 to 14 days, says Dr. Gan.

“If your child has these symptoms you should take him or her to a doctor,” says Dr. Gan.

The common cold usually causes clear nasal discharge and low-grade fever. The clear discharge from a viral cold can turn green after three to four days and usually gets better in seven to 10 days (viral colds often cause a green nasal discharge and the colored drainage is not necessarily indicative of sinusitis, which is a bacterial infection). Allergies also will not cause fever or colored discharge, and allergies become worse when your child is around the offending substance.

Treatment for a sinus infection includes antibiotics, decongestants and nasal irrigation with saline and nasal sprays to help open up the nasal blockage. Dr. Gan warns not to use nasal decongestant sprays for more than three to five consecutive days, since they can worsen swelling after that. “It’s also very important to drink more water,” says Dr. Gan.

For persistent or chronic sinusitis, surgery may be necessary to widen the sinus channels.

It’s important for your child’s sinuses to remain moist. This keeps secretions thin and allows them to flow easily, improving breathing and reducing the chance of infection. Here’s a recipe to keep your child’s nasal passages from becoming too dry:

1 cup of water.
1/2 teaspoon of kosher salt or pickling salt.
Mix, boil and use when cool.
Spray or drop this solution in nasal passages several times a day.
Don’t allow the mixture to sit around too long, as this is a source of bacterial overgrowth.