# Do we know for sure that allergies were under-diagnosed in the past ?

**URL:** <https://boards.straightdope.com/t/do-we-know-for-sure-that-allergies-were-under-diagnosed-in-the-past/854472>\
**Category:** Factual Questions\
**Created:** [May 26, 2020, 1:18am UTC](https://boards.straightdope.com/t/do-we-know-for-sure-that-allergies-were-under-diagnosed-in-the-past/854472 "2020-05-26T01:18:12Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![am77494](https://avatars.discourse-cdn.com/v4/letter/a/d2c977/32.png) [@am77494](https://boards.straightdope.com/u/am77494)\
**Post date:** [May 26, 2020, 1:18am UTC](https://boards.straightdope.com/t/do-we-know-for-sure-that-allergies-were-under-diagnosed-in-the-past/854472/1 "2020-05-26T01:18:12Z")

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Per my understanding, the cause for allergies is not fully understood. There was the cleanliness theory which has been debunked.

Do we know for sure that there is real increased instances of allergies in the population ? Or was the same percent of population had allergies in the past but were under diagnosed ?

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**Author:** ![Wendell\_Wagner](https://avatars.discourse-cdn.com/v4/letter/w/8491ac/32.png) [@Wendell\_Wagner](https://boards.straightdope.com/u/Wendell_Wagner)\
**Post date:** [May 26, 2020, 1:48am UTC](https://boards.straightdope.com/t/do-we-know-for-sure-that-allergies-were-under-diagnosed-in-the-past/854472/2 "2020-05-26T01:48:35Z")

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As far as I’ve been able to determine in a quick online search, the hygiene hypothesis has only been partly debunked:

> **[Time to abandon the hygiene hypothesis: new perspectives on allergic
disease,...](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4966430/)**
>
> To review the burden of allergic and infectious diseases and the evidence for
> a link to microbial exposure, the human microbiome and immune system, and to
> assess whether we could develop lifestyles which reconnect us with exposures
> which could reduce...

> **[The hygiene hypothesis is out of date and is undermining public health](https://medicalxpress.com/news/2019-03-hygiene-hypothesis-date-undermining-health.html)**
>
> Researchers are concerned that attitudes to hygiene are being undermined by the hygiene hypothesis, and that this misleading misnomer could contribute to the spread of infectious disease.

> **[Hygiene hypothesis](https://en.wikipedia.org/wiki/Hygiene_hypothesis)**
>
> In medicine, the hygiene hypothesis states that early childhood exposure to particular microorganisms (such as the gut flora and helminth parasites) protects against allergic diseases by contributing to the development of the immune system. In particular, a lack of exposure is thought to lead to defects in the establishment of immune tolerance. The time period for exposure begins in utero and ends at school age.
> While early versions of the hypothesis referred to exposure to microbes in general...

The sorts of things that exposure to is good for one’s health is more limited than was proposed in the earlier versions of the hypothesis. Some things are good to be exposed to. Some aren’t.

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**Author:** ![nearwildheaven](https://avatars.discourse-cdn.com/v4/letter/n/90db22/32.png) [@nearwildheaven](https://boards.straightdope.com/u/nearwildheaven)\
**Post date:** [May 26, 2020, 3:34am UTC](https://boards.straightdope.com/t/do-we-know-for-sure-that-allergies-were-under-diagnosed-in-the-past/854472/3 "2020-05-26T03:34:19Z")

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When my mother was a kid in the 1940s, she had a friend who regularly saw a chiropractor for her allergies. Hey, it worked as well as anything they had available at the time.

I do wonder how many of the “frail, sickly children” of past generations actually had some variant of allergies or food or environmental intolerances.