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What's Behind the Increase in Childhood Allergies?

How environmental factors might cause childhood allergies

Scripps Health immunologist, Jennifer Namazy, MD, on the noted increase in childhood allergies.

How environmental factors might cause childhood allergies

Hand sanitizers and household cleaners have changed the way we prevent the spread of germs. But in the quest to avoid the common cold, are we priming younger generations to develop allergies?

“That’s the million dollar question and what has sparked what we call the hygiene hypothesis,” says Jennifer Namazy, MD, an immunologist at Scripps Clinic. “When you look at the issue of allergies globally, people in Western countries tend to have more allergies than those in developing countries. So is there something we’re doing to our environment that’s making us more susceptible? Maybe we’re being too clean and our immune systems, with nothing else to do, are starting to fight the wrong things.”

An allergy is when your immune system responds to something that would otherwise be harmless such as food, pollen or pet dander. Reactions can range from a rash, itching and a runny nose to more severe symptoms such as mouth swelling, tongue swelling and anaphylaxis.

The prevalence of allergies has been steadily increasing with an estimated one in five Americans suffering from any sort of allergy. A report by the CDC found that from 1997 to 2007, food allergies among children under 18 years of age rose by 18 percent.

Could early exposure reduce allergies?

A recent study investigated the hygiene hypothesis, examining how parents chose to clean their child’s pacifier. Parents who placed the pacifier into their own mouth to “clean” it before giving it to their child had children that were less likely to develop asthma, eczema or food allergies than parents who used other cleaning techniques.

“A lot of our immune system is in our gut, and together with the bacteria that live there, help develop tolerance to potential allergens,” explains Dr. Namazy. “When you look at kids that grow up on farms, they have a low amount of allergies. This could be because they drink unpasteurized milk, which has bacteria in it. So it makes sense that from drinking unpasteurized milk to a mother’s oral bacteria, exposing the gut to the right bacteria could help prevent the onset of allergies.”

Early exposure to other potential allergens could have similar benefits. Recent studies have shown that children who live with indoor pets for the first year of life are less likely to develop pet allergies.

Exposing kids to pets or changing their diet isn’t a sure-fire way to prevent allergies. In fact, reducing cleanliness or eating unpasteurized foods could expose your child to potentially dangerous germs. “There aren’t any clear answers right now on how to prevent allergies from developing,” says Dr. Namazy. She notes that there are several factors—including genetics—that can make a child prone to developing allergies.

Managing allergy symptoms

Fortunately, there are many treatment options to help children including medications to reduce symptoms and allergen immunotherapy.

“Immunotherapy is a series of injections that are designed to help retrain the immune system to not produce an allergic response,” notes Dr. Namazy. "This treatment option is more effective the younger you are, and it could potentially help a child reduce the chance of developing new allergen sensitivities.