For many families, a new school year means new cases of the sniffles.

Knowing how and when to treat children with colds is a constant struggle for most parents. "Kids get colds more often than adults on the order of once every month or the average of eight to 10 per year. And that's because their immune systems aren't as strong as ours," says Pediatrician Dr. Jennifer Shu.

Colds are caused by viruses, and the all-too-familiar symptoms can include a runny nose, cough, fever, sneezing and irritability. Dr. Shu says a cold can last for two or three weeks, however the worst symptoms tend to pass after a few days.

According to the American Academy of Pediatrics, parents shouldn't give kids under age four over-the-counter cough and cold medicines because they can be harmful. For a fever , the AAP recommends acetaminophen for infants from birth to six months of age.

Once they're six months or older, it says it's OK to give them acetaminophen or ibuprofen. "Over the age of two, kids tend to handle fevers a little bit better. So I tend to say treat the child and not the fever, so if there's a really high fever, but the child is acting well then you don't have to get too concerned," says Shu.

Even though colds aren't curable, Shu says the bright side is that every time that your child does get a cold, it does strengthen their immune system.