The news is full of articles about allergy in children. What is happening? Is allergy more common today and why? In today’s pedcast, Dr. Smolen gives you some of his and other physician’s thoughts on the increasing frequency of allergy in today’s world.
To my new listeners, thank you.
To my seasoned listeners, welcome back.
I was reading the Wall Street Journal of all place and having coffee with the Mrs..
I came across a report about an article in New England Medical Journal, which points out that farm life exposes children to far more microbes and this early exposure significantly reduces a child’s chance of asthma or eczema.
This observation is a big help to researchers since they are struggling to explain the obvious increase incidence of all allergic disorders, especially in children.
The subject of allergy is a hot, hot issue in medicine and one of the important questions when it comes to children’s health: why so much allergic disease???
I am not an allergist but I am someone who deals with matters of children’s health on a daily basis and I have the perspective of time to observe changes.
I therefore feel that I may have something to contribute to the discussion.
I thought it is important to make parents aware of some research that might have practical implications to their day-to-day lives.
So, lets get started with a our discussion of allergy. Let’s review some research I found interesting, and give you The DocSmo view of the allergy epidemic of the 20th and 21st centuries in the western world.
Somehow our bodies know what is us, and what is foreign.
Somehow our bodies figure out how to sort out what foreign things to react to and which to ignore.
Reacting to germs is an essential part of that process. Particularly important for children.
A strong immune system is paramount to a child’s existence. Their very survival depends on a functioning immune response.
From the beginning of mankind, the children who survived were those who could mount a targeted, brisk immune response to invasion. A strong and targeted immune function was essential to survival.
Fast forward to modern times, when immunizations, clean water and food etc. have eliminated most of these threats to survival.
Today most children grow up in a very clean world, very different from his or her parents just a few generations ago.
Just because the germs are mostly gone doesn’t mean their bodies have forgotten what to do! Could the kid’s immune system simply be bored?
Maybe since children don’t have to defend against as many microbes, they are having responses to more minor irritants.
What we call allergy is an inappropriate immune responses to things that children should be tolerant!
These immune responses are so critical to a child’s survival 200 years ago, but are now targeting nonsense threats like peanuts and grass pollen.
With that as background, let’s look at the numbers when it comes to allergic diseases…food allergy,. Asthma, eczema, and allergic rhinitis (hay fever) ESTIMATES vary widely.
Food allergy… up 400%
Asthma… up 1000%
Eczema ….up 300%
Hay fever …up 200 %
I was taught that these disorders are genetic, Either you get them or you don’t.
Certainly our genes haven’t changed radically in the past 100 years.
What is up? Why is this happening?
Here are a few recent research studies that might shed some light on this question.
Lets go back in time a few decades when the Berlin wall in Germany was built.
One side Germans living the Western lifestyle, modern, wealthy, clean, artificial ventilation for both heat and cold, and all the other stuff that we enjoy today.
On the communist side were Germans living the lifestyle that existed in the late 19th century: dirty industry, primitive heating systems such as burning coal or wood, dirty air and water, and fairly ubiquitous poverty.
Fast-forward until the year 1989. The wall comes down Mr. Gorbachov, tear this wall down. Well, the people on both sides did just that.
Perfect natural experiment to look at the affect of environment on people. Same genetic populations, living side-by-side…totally different environments.
What did researches find? Rates of allergic disease (asthma, hay fever, eczema) were much higher on the clean side of the wall rather than the dirty. The OPPOSITE of what you would have expected! Maybe the West Germans were TOO clean.
Lets get back to that NEJM article this week. Children who are exposed to barns at an earlier age and more frequently have a significantly LOWER incidence of Asthma and eczema.
What’s going on in a barn: dirt, animal wastes and a lot of pollen, especially grass pollen.
Being exposed to dirt and germs , especially at a young age, seems to be protective when it comes to allergies.
The opposite of what was expected.
Again, maybe the city kids are too clean?
These observations and many others have led to what is called the Hygiene Hypothesis. A child’s immune responses and tolerance to the world are altered negatively by lack of exposure to dirt and germs early in life.
Could it be that western children are growing up in a world that is TOO clean and this is causing the rather precipitous rise in allergic disease seen especially in the past 50 years.
Maybe we are creating the problem of allergy by staying inside with artificial heat and cold so much, eating super clean water and food, sleeping on clean artificial bedding , constantly scrubbing dirt off as fast as it touches our children, our obsession with clean hands, not living with animals, and changing the natural grasses, trees and other vegetation in our constant quest to change the natural order around us.
Makes sense to me that if allergy shots can alter immune response and make us tolerant. So could natural exposure.
The answers are not in yet but we are beginning to get an understanding of the complexity of our immune system .
–Question coming in;
Question: Doc Smo, This is your friend Her Dieter from Germany. I have a question. If I am hearing you right, you are saying that my little venarschnitzels are too clean, and that they need more time getting exposed to microbes, especially the kind found outside. Is that right?
You got it. Lot less allergic disease in those children who slop them pigs, shuck some corn, and spend time on the old farm. The same is probably true for any child who spends a lot of time outside.
Question: How do the experts feel about dogs and cats in the house. Do they help or hurt allergic children?
Good question. From my reading the answer is both. Exposure to furry creatures like dogs and cats in the house in the first year of life seems to diminish the chance that a child will develop asthma. On the other hand, exposure to animals such as dogs and cats in older, already allergic children often makes their allergic symptoms much worse. I know that answer is as clear as mud but that’s the best I have.
Question: Is the same thing true for food allergy? I thought early exposure was bad! Is there a way to keep my little snitzels from being allergic to certain food?
That is a subject for an entirely different Pedcast but let’s just say that avoiding early exposure to very allergenic foods have not reduce the incidence of food allergy.
The truth is, We just don’t know the best age to introduce allergenic foods
We do know that breastfeeding reduces allergic disease especially eczema
(In fact, in another natural experiment with peanut exposure…conclusion was early exposure is preferable!)
Summary- “When it comes to Allergy”
Early experiences change the way our immune system develops.
New research indicates that early exposure to a variety and high quantity of germs lessens the chance of allergic disease, if the exposure is done early!
-Growing up in a too clean environment may harm a child’s health.
Her are some steps parents can take that might help reduce allergic disease in their children.
Breastfeeding as long as possible.
Get your children outside as often as you can.
Turn of the A/C and heat whenever possible and open those windows.
Hand hygiene is really important when your children are spending lots of indoor time with other kids but not when they are at the park. Outdoor dirt won’t hurt. Calm down about outside dirt.
When it comes to allergy, furry pets in the house seem to be harmful to older already allergic children but may, and I emphasis may actually be of benefit to very young non-allergic children.
Allergies are probably similar to other biologic phenomena—a complex interaction of genetics and environment. Back to that nature /nuture question-again
Hope you enjoyed that discussion
Please feel free to make comments on iTunes or Face book are welcome
Invite your friends to subscribe.
If you are a medical professional and would like to send comments-highlight on blog
More reading can be found in SmoNotes
Dr Paul Smolen, broadcasting from studio 1 E, Queen City, Charlotte, NC
Hoping your children get just the right amount of dirt on their toes and pollen in their nose
Until next time.
NICOLAI, T.. “Epidemiology of Pollution-induced Airway Disease: Urban/rural Differences in East and West Germany.”
Allergy : European Journal of Allergy and Clinical Immunology 52.38 (1997): 26-29. Web. 10 Mar. 2011.
Ring, J. et al “Environmental Risk Factors for Respiratory and Skin Atopy: Results from Epidemiological Studies in Former East and West Germany.” International Archives of Allergy and Immunology 118.2-4 (1999): 403-407. Web. 10 Mar. 2011. <
Bacharier, Leonard B., and Robert C. Strunk “Pets and Childhood Asthma—How Should the Pediatrician Respond to New Information That Pets May Prevent Asthma?” Official Journal of the American Academy of Pediatrics 112.4 (2003): 974-976. Web. 10 Mar. 2011. <http://pediatrics.aappublications.org/cgi/content/full/112/4/974>.
Wang, Shirley S. “Greater Germ Exposure Cuts Asthma Risk.” Wall Street Journal 23 Feb. 2011: 1A. Web. 10 Mar. 2011 <
Greer, Frank R., Scott H. Sicherer, and Wesley Burks “Effects of Early Nutritional Interventions on the Development of Atopic Disease in Infants and Children: The Role of Maternal Dietary Restriction, Breastfeeding, Timing of Introduction of Complementary Foods, and Hydrolyzed Formulas.” American Academy of Pediatrics 121.1 (2008): 183-191. Web. 10 Mar. 2011. <
Toit, G. et al “Different Prevalence of Peanut Allergy in Children in Israel and UK Is Not due to Differences in Atopy.” Allergy and Clinical Immunology 117.2 (2006): S33. Web. 10 Mar. 2011. <http://www.jacionline.org/article/S0091-6749(05)02857-5/fulltext>.
Ege, Markus J. et al “Exposure to Environmental Microorganisms and Childhood Asthma.” New England Journal of Medicine364.1 (2011): 701-709. Web. 10 Mar. 2011. <http://www.nejm.org/doi/full/10.1056/NEJMoa1007302>.
Subscribe on iTunes!
*By listening to this pedcast, you are agreeing to Doc Smo’s terms and conditions.