Shots - Health Blog
1:31 am
Mon June 11, 2012

To Sniff Out Childhood Allergies, Researchers Head To The Farm

Originally published on Tue June 12, 2012 8:11 am

Allergies are on the rise these days, especially in children. Nearly half of all kids are now allergic to something, be it food, animals, or plants. Federal health officials say that rate is two to five times higher than it was 30 years ago.

And as researchers are trying to understand why, they're increasingly looking at kids who grow up on farms.

The leading theory behind the uptick in childhood allergies, says Andy Nish, a physician with a private practice in Gainesville, Ga., is the hygiene hypothesis. Paradoxically, the theory goes, we're too clean.

"It looks like with our modern conditions and cleanliness that we have fewer and fewer germs to fight off," Nish says. Our immune systems protect us by learning to fight off foreign invaders, whether they're harmless or not. We can't train our defenses if we don't get exposed. And if you're allergic to one thing, you're likely allergic to a number of things.

Take 16-year-old Casey, one of Nish's patients, who recently went in for a routine check-up. Nish says Casey has a host of allergic diseases, including hay fever, asthma, and eczema that's gotten milder as he's aged. "He's definitely an example of someone who is allergic," Nish says.

Nish peers into Casey's ears and mouth, and checks his neck for lymph nodes. He's looking for the telltale signs of allergy: runny nose; itchy, watery eyes; sneezing. Casey's nose is a bit congested, but it's not too bad.

Casey's allergies include dust mites, cats, and certain grasses and weeds. The hygiene hypothesis suggests that Casey's immune system never learned how to deal with those natural substances – hence the allergies. And the theory is bolstered by evidence from farms.

Studies show children who live on farms have low rates of allergies. Dr. Mark Holbreich, an allergist in Indianapolis and a fellow of the American Academy of Allergy, Asthma and Immunology, calls it "the farm effect."

Holbreich recently did a study, published in the Journal of Allergy and Clinical Immunology, which found very low rates of allergies among Amish children living on farms in Indiana. He says the reason may be because the children get exposed very early on to dirty environments, and to a variety of dust and germs. Even young kids are often in the barn, working with animals, and drinking raw milk.

"We think there's something about milk," Holbreich says. "That's key, along with exposure to large animals, particularly cows."

Scientists don't know exactly what it is in raw milk, or in the barn, or on the cows, that helps boost the immune system. They're researching that now. But Holbreich cautions against drinking raw milk or serving it to your child. It contains too many dangerous, disease-causing bacteria.

There are other theories about why allergies are rising. Taking antibiotics early in life may be a factor. Tightly constructed homes with little ventilation may foster allergies. And today people stay inside for longer periods of time, not exposing themselves to the great outdoors.

But if you have allergies, Nish says, you shouldn't despair. "There's good treatment out there and there's no need to suffer," he says.

There's a host of medications to treat symptoms. Antibiotics are commonly prescribed. There are over the counter anti histamines and decongestants. And there's a nasal steroid spray, which Nish says can help to decrease inflammation in your nose. Studies show the spray benefits some patients.

But the closest thing to a cure, says Nish, is allergy shots – that is, injections of the actual allergic substance. They're given in small doses, he says, "to sneak it past the immune system," and slowly build up the body's tolerance to the substances that cause allergies.

After a few months, allergies are usually under control. And, after a few years, patients can usually stop the shots altogether.

Copyright 2013 NPR. To see more, visit http://www.npr.org/.

Transcript

RENEE MONTAGNE, HOST:

And another health problem on the rise - allergies, especially in children. Nearly half of all children are now allergic to something, whether it's food, animals or plants. NPR's Patti Neighmond has that story.

PATTI NEIGHMOND, BYLINE: Dr. Andy Nish is in private practice in Gainesville, Georgia. Today he's seeing 16-year-old Casey, who's here for a routine check-up.

DR. ANDY NISH: So ears look good. Open mouth real big, say ahh.

CASEY: Ahh.

NISH: OK. Good.

NEIGHMOND: Nish is looking for telltale signs of allergy - runny nose, itchy, watery eyes, sneezing. Casey's nose is a bit congested but it's not too bad.

NISH: All righty. Don't feel any lymph nodes in your neck. That's good. Take a listen to your breathing - big breaths.

(SOUNDBITE OF DEEP BREATHING)

NEIGHMOND: Casey's allergic to dust, mites, cats, certain grasses and certain weeds.

NISH: He definitely has the three main, what we call atopic diseases, which would be allergic rhinitis or hay fever, asthma. And then he had more eczema when he was younger. And now he has more dry skin and these little bumps called keratosis pilaris. So, yes, he's definitely an example of somebody who is allergic.

NEIGHMOND: If you're allergic to one thing, chances are you're allergic to a number of things. Federal health officials say the rate of allergies among children in the U.S. today is two to five times higher than it was 30 years ago. Researchers are trying to understand why. The leading theory: the hygiene hypothesis.

NISH: It looks like with our modern living conditions and cleanliness that we have fewer and fewer germs to fight off.

NEIGHMOND: Which means our immune system doesn't get trained to recognize and fight foreign invaders, whether they're harmless or not. The theory is bolstered by evidence from farms. Studies show children who live on farms have low rates of allergies.

Dr. Mark Holbreich is an allergist in Indianapolis and a fellow of the American Academy of Allergy, Asthma and Immunology.

DR. MARK HOLBREICH: The farm effect is the fact that children seem to live on traditional farms have a lower prevalence of allergic diseases such as asthma and allergies.

NEIGHMOND: Holbreich recently did a study which found very low rates of allergies among Amish children living on farms in Indiana. He says the children may be protected because they get exposed early on to dirty environments and variety of dust and germs.

HOLBREICH: Actually when the mother's pregnant with the child and living working on the farm, working in the barn, drinking raw milk and then once the child is born on Amish farms, the children are very often at barn at young age, and when they're weaned from the breast, then they start drinking raw milk. And we think that there's something about unpasteurized and un-homogenized milk that is the key, along with exposure to large animals, particularly cows.

NEIGHMOND: Scientists don't know exactly what it is in raw milk, or in the barn, or on the cows that may boost the immune system. They're researching that now. But Holbreich cautions against drinking raw milk or serving it to your child. He says it contains far too many disease-causing bacteria.

There are other theories about why allergies are on the rise. Taking antibiotics early in life may be a factor. Tightly constructed homes with little ventilation may foster allergies. And today people stay inside for longer periods of time, not exposing themselves to the great outdoors.

But if you have allergies, Dr. Andy Nish says, you shouldn't despair.

NISH: There's good treatment out there and there's no need to suffer.

NEIGHMOND: There are lots of medications to treat symptoms of effectively. Antibiotics are commonly prescribed. There are over-the-counter anti-histamines and decongestants. And there's a nasal steroid sprays.

NISH: They help to decrease inflammation in your nose and they work over time so should be taken daily.

NEIGHMOND: But the closest thing to a cure, says Nish, allergy shots, injections of the actual allergic substance.

NISH: And so the allergy shots are to specifically to what that person is allergic and they're given in very small doses to - if you will - sneak it past the immune system.

NEIGHMOND: And slowly build up the body's tolerance. After a few months, allergies are usually under control. And after a few years, patients can usually stop the shots altogether.

Patti Neighmond, NPR News.

(SOUNDBITE OF MUSIC)

MONTAGNE: You're listening to MORNING EDITION from NPR News. Transcript provided by NPR, Copyright NPR.