What to Do About Recurring Illnesses

 system that's been coddled by a hyperclean home. "That's the hygiene hypothesis," says Dr. Kimberlin. "Children's immune systems are designed to learn from exposure to all sorts of things. But researchers increasingly

 believe that our modern environment may be too clean. As a result, kids aren't building the immunity needed to resist certain illnesses."3

Kids with upper respiratory allergies may also get more colds than normal, he adds. The reason? Inflammation of the upper respiratory system can make a child more susceptible to cold germs, or make cold symptoms more pronounced.

Some endless rounds of runny noses may simply be a case of bad timing: Newborns inherit short-term common-cold immunity from their birthing parent, but it wears off after about six months. This leaves summer-born babies without protection just as the winter sneeze season kicks into gear.

Advice for Parents

Make sure kids get lots of sleep. If they're eating solid foods, include plenty of fruits and veggies in their diet. In adults, low levels of vitamin C might possibly be linked to harsher colds.4

Also, don't smoke in the house, or even better, try to quit. Exposure to

 secondhand smoke—even the burnt-tobacco by-products that cling to clothing and furniture—irritates airways and dulls immunity, raising the

 risk of a child's cold becoming something worse. According to the Centers for Disease Control and Prevention (CDC), secondhand smoke causes numerous health problems in infants and children, including more frequent and severe asthma attacks, respiratory infections, and ear infections.5

It's important for parents to keep in mind that COVID-19 can be a cause of cold symptoms, especially in young children. If your child is presenting with cold symptoms, it's a good idea to perform an at-home COVID test before sending them to school or daycare.

Croup

Croup is a viral infection that leads to swollen airways and a scary-sounding "barking" cough. The characteristic cough is a result of constriction of the airways in the upper respiratory system. Up to half of all kids who've had one episode of croup will go through it again, researchers estimate.6 Why? Reasons range from physical anatomy to genetics to prematurity. While croup sounds quite scary, it's typically a mild virus.

What's Normal

At least one bout of croup by age 3.

What's Not Normal

When breathing becomes a serious struggle for your child.

Why Your Child Might Be Vulnerable to Croup

Croup is more likely to strike in the fall and early winter, and it's slightly more common in boys than in girls.

One risk is being born with a narrower-than-usual voice box (larynx) and windpipe (trachea). The tiniest portion of the windpipe, the subglottic trachea, swells during croup. Pediatricians are also realizing that the