Allergies and asthma are on the rise among children in the US, which has parents and the medical community scratching (haha) their heads as to why, and what can be done about it. As many as half of all 3-year-olds in the United States suffer from wheezing illnesses. Recurrent wheezing and allergies are considered a risk factor for asthma in later life. According to the American Lung Association, asthma remains one of the most common pediatric illnesses, affecting about 7 million American children.

Physicians specializing in asthma, allergies and immunology agree that a body’s immune system plays an important role in either reducing, or increasing, a child’s likelihood of developing allergies or asthma.

Infants have a weak immune system, which develops with exposure to the environment. Other factors that affect children’s immune systems are: genetics, diet, and health/socio-economic stress factors.

So what should parents do to help their children’s immune systems develop in the most heathy way? Apparently, given recent research, be a little dirtier….

Infants are much less likely to suffer from allergies or wheezing if they are exposed to common household germs and bacteria, a recent study from John Hopkins Children’s Center in Baltimore confirms.

The findings have been dubbed the “hygiene hypothesis,” which holds that children in overly clean houses are more apt to suffer allergies because their bodies don’t have the opportunity to develop appropriate responses to allergens.

This research supports what we’ve known for a while: that asthma and allergies are less common among children who: grow up on farms, have early contact with other children (siblings/day care), or live in a house with furry animals. While kind of gross, it would appear that stimulating a child’s immune system with a little exposure to dirt (bacteria) and allergens (animal dander, bug droppings) is a good thing.

So should parents let their kids eat dirt?

The science isn’t complete, and the medical community isn’t in total agreement about what this means for parents. But some guidelines we can agree to depend on your child’s age.

Infants: because of how immature their immune systems are, cleanliness is important. It’s important to wash hands before allowing folks to hold a newborn, or asking others who are sick to stay away.

By the time your baby is a couple of months old, you won’t need to be quite as vigilant. As your baby grows, the immune system strengthens, and continues to do so through the toddler stage and beyond.

Also, parents should be careful about the cleaning products they use. Aerosols are particularly concerning: spray de-greasers, bleach solutions, and air fresheners are more likely to trigger respiratory symptoms, such as coughing and wheezing, that people associate with allergies.

The take-away

While it may sound counterintuitive, parents can stress less about cleanliness. If your child picks up a bug, or pacifiers at daycare get mixed up, or the family dog licks your child’s face, we know they’ll live – and maybe, live with a stronger immune system. A couple of germs might just be what the doctor ordered.