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Comment by outlace | Hacker News Reader

Per the hygiene hypothesis, I wonder if your allergies got better because you’re exposing yourself to more (generally harmless) microorganisms and hence challenging your immune system more. Since I’m sure lactic acid doesn’t sterilize as well as some strong bleach or other chemical.

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Anecdata: my wife’s allergies come and go quite predictably switching between regular and hypoallergenic soaps and laundry detergents. Especially with laundry detergent a single load with the wrong detergent can have her sneezing all day. That doesn’t fit the micro organism exposure theory.

Myself I have an allergy to grass pollen, but the catalyst that really brings it out is car exhaust. Personally I believe that the chemicals in our environment are catalysts for natural sensitivities, turning them into allergies.

Sounds just like me. One thing at a time can be ok but combinations really triggers. Sneezing constantly for hours is not fun. Antihistamin helps a lot by removing the pollen side and then I can stand the bad air pollution from cars.

Friends washing their clothes in perfume however there is no cure for yet.

This is still compatible with the hygiene hypothesis. It could be that your wife grew up in a “too clean” environment and hence her immune system became hypersensitive to substances that anybody in a less clean developing country would have no issues with. She has legitimate allergies; the hygiene hypothesis just tries to explain why many people get allergies in the first place.

A hypothesis which permits compatibility with any reality it is of limited practical value.

If it's ultimately not falsifiable, it's not science.

It’s a completely testable and falsifiable hypothesis. The original commenter seemed to be dismissing the hypothesis based on an anecdote that he thought falsified the hypothesis and I was pointing out that it does not. Of course any hypothesis that cannot be falsified is not worth entertaining.

How would you falsify your hypothesis that the wife's allergies are from a "too clean" environment?

You can’t, in general, test something that already happened. Moreover, given the immune system is a complex system with some degree of randomness involved, it would probably be impossible to prove that any particular person’s allergies were caused by a too clean environment. But we can certainly study it at a population level and it can be falsified with populations.

This is similar to smoking. Smoking is a good explanation for a large amount of the cases of lung disease at the population level and is falsifiable at that level. But it is impossible to say that smoking caused a particular person’s lung cancer.

So my original comment of “I wonder if...” is just that. A musing, not a hypothesis. I can’t prove anything for a particular person. But maybe more people will be aware of the hygiene hypothesis and might take it into consideration.

So how would you falsify “the population with his wife’s allergy often get it from sources other than a too clean environment”?

I recently (in the last 3 weeks) developed an allergy to heavily fragranced laundry detergent. It's the first persistent allergic reaction I've really ever had. We usually use a very mild unscented detergent but my mother in law was staying with us for a little while and uses Tide and she washed some of my clothes. I generally have sensitive skin and so it was quite a shock. I was bruising all over my body just from light but compulsory scratching. It seems to have passed but it's given me a new found appreciation for using mild chemicals for cleaning, etc...

The idea that allergies somehow are caused by our sterile lifestyle is suspicious at best. It's might just be an appeal to nature - "all natural ingredients" fallacy.

I claim that an individual has never before - in the history of mankind - been exposed to so many and different microorganisms as we are now.

Comparing my daughter to my granddad, born 99 years before her, she probably meets as many "new" people per week - if not day, as he did in a whole year when growing up in a reasonably average community not far from a large city.

Me and my wife works in large organisations, and it's representatives are visiting or are visited by hundreds of people from around the world - every week, as do many - most in fact - of the other parents in her school of about 1000 students.

I have lunch in a canteen where approximately 3000 people eat every day, and we all are slopping around in the food warmers and salad bar sharing the utensils and pawing the bread with our halfheartedly washed hands.

On the way to our offices and schools we commute with thousands and thousands of people, all sniffling and coughing it seems.

The interconnectedness of it all is just - mind boggling. We are never more than 2 steps away from someone that were on the other side of the world, yesterday. Hopefully not in an Ebola zone.

A hypothetical "natural" state, where you sleep in a stack of hay with your pigs, and meet one "outsider" twice a a year doesn't seem to tax the immune system even a fraction of what we have to deal with today. Even it's a lot of microorganisms, it's yours (and the pigs) - unless some pigeons shit in your haystack/bed.

The body of scientific evidence supporting the hygiene hypothesis is pretty strong.

I am reading An Epidemic of Absence (http://www.moisesvm.com/) which explores the hypothesis and it presents a plethora of cases and studies that support it. I have not searched for counter points but it seems pretty solid to me. I can recommend the book by the way.

One major thing we are no longer exposed to are parasites. Those were common before but they are now pretty much inexistant in western civilization.

i doubt you exchange bodily fluids with 1000s of people around you. maybe some, but not 1000s. AC and recycled air, on the other hand, are completely devoid of microorganisms that travel through the air. allergies is a north american thing, virtually unknown to other parts of the world.

EDIT: AC and the recycled air is the actual point of this comment. fluids was the joke, apologies to offended. north america breathes AC recycled air. no one else does. at least not to this extent. at the same time, one of the standard conversation topics amongst immigrants (to NA) is "wtf does everyone here have allergies and what are they anyway?". until they develop their own after living here for a number of years.

I never cleaned much before. I think the key is that I now get rid of some nasty allergens very efficiently (e.g dust mites or diesel fumes with my air filter) and I don't spread around artificial fragrances.

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