But doctors do know how sinuses function. Lined by the same type of mucous membranes that coat the back of your nose and 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
• Secondhand smoke

These factors may contribute to each other. For instance, a child is more likely to develop allergies and sinus trouble if one or both parents tend to be congested, explains Dr. Vanthaya Gan, a pediatrician on the medical staff at Children’s Medical Center Dallas. “If that child is allergic or exposed to secondhand smoke, the condition could worsen.”

Exposure to allergens and secondhand 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 above 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. Your child simply won’t feel as ill from a cold as from sinusitis. And, 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.