Talk:Multiple chemical sensitivity

Sense of smell that disturbs people

@Daniel Santos, your profanity-laced edit summary indicates that you think "a disturbingly acute sense of smell" is unencyclopedic language. This isn't yellow journalism: it's a straight-up description of the facts. Some MCSers have – or are dismissed as "only" having by healthcare providers – a sense of smell that goes beyond the ordinary level of acute (e.g., "mother can smell cigarette smoke on her teenager at 20 paces"), but is so acute that it disturbs their everyday lives, hence "disturbingly acute". How would you prefer to indicate that this is not "merely" an acute sense of smell, but an extreme version of that? WhatamIdoing (talk) 03:34, 23 October 2024 (UTC)

Chemicals that have no smell can also cause MCS reactions. For example masking fragrance has given me hives, headaches, and dizziness.

Fortunately, my MCS has been significantly helped since I started taking N-Acetyl Cysteine (NAC).

NAC: "NAC supports the liver in detoxifying harmful substances. It restores glutathione levels."

Glutathione:

• "Antioxidant Function: Glutathione neutralizes free radicals and reactive oxygen species, preventing oxidative stress that can damage cells, DNA, and tissues.
• Detoxification: It helps the liver detoxify harmful substances, including drugs, pollutants, and heavy metals, by binding to toxins and aiding their excretion.
• Immune Support: Glutathione supports immune function by maintaining the activity of immune cells and reducing inflammation."

108.18.208.58 (talk) 06:15, 16 April 2025 (UTC)

Masking fragrance has a smell; that's how it works. WhatamIdoing (talk) 16:47, 16 April 2025 (UTC)

"unrecognized" but bulk seesm to disagree

The article say (correctly) that5 this is unrecognized, but the bulk of the article has a rather different tone. jae (talk) 09:56, 13 June 2025 (UTC)

Thanks for your note, @Jae. I'm sure the article needs work. It has been difficult to get outdated sources and mindsets out of the article – it's like we all read up on MCS two or three decades ago, and we haven't updated our understanding since then. Maybe I'll be able to make some time to work on it this summer.

The general difficulty with this subject is that the answer depends on what you mean when you say "MCS". If you mean, e.g., that the guy in the 1950s was right and it's a true immune-mediated allergy, then that was proven completely wrong decades ago.

If you say that your neighbor seems to get sick when she smells certain things, then conventional Western medicine accepts that. However, if this same neighbor says that the symptoms were originally caused by "chemicals", then that's uncertain. It's more likely that MCS is actually caused by your neighbor's unlucky brain [e.g., a type of post-concussion syndrome] but the symptoms are exacerbated or triggered by smells.

For an analogy, migraine is caused by the brain but may be triggered in different people by stress, hormonal changes, bright/blinking lights, etc. If you don't have a migraine-susceptible brain, then blinking lights may be annoying (or you might love, e.g., a laser show at a concert or a strobe light in a club), but the blinking lights won't trigger a migraine. If you do have a migraine brain, then the blinking light doesn't really cause you to have a migraine brain; it just makes your pre-existing migraine brain produce migraine symptoms. WhatamIdoing (talk) 18:31, 13 June 2025 (UTC)

Could you please explain your reversions in more detail ?

boncourage

I don't understand how it misrepresents MedRS as it does not explicitly state say anything about amending an accessed date after verifying that the information is still correct as presented in the use of the source

And it seems like your reversion of my removing the {{obsolete source}} markers is agreeing with my removal of them. if more recent sourcing exists, then it should have been added unless you were unable to find more recent sourcing ?

if you could please explain in more detail so I can better understand as I'd like to use this as an opportunity to become a more competent editor

Thank you in advance and kind regards, tiredkitty (talk) 17:32, 25 March 2026 (UTC)

Refer to WP:MEDDATE. Yes, we do want sources < 5 years old when they are available (N.B. "These instructions are appropriate for actively researched areas") but for many more niche topics they simply aren't. For historical information older sources are obviously fine. Are there newer MEDRS for this topic? Bon courage (talk) 17:38, 25 March 2026 (UTC)

I have the 2021 (6th edition) of Harrison's "Multiple Chemical Sensitivity" chapter in Current Occupational & Environmental Medicine. It is largely the same as the 2014 version, though there have been a few updates. WhatamIdoing (talk) 17:44, 25 March 2026 (UTC)

Cool. You know what to do Bon courage (talk) 17:47, 25 March 2026 (UTC)

Um, e-mail a copy of the text to you? WhatamIdoing (talk) 18:24, 25 March 2026 (UTC)

I can add it to my to-do list . Bon courage (talk) 18:29, 25 March 2026 (UTC)

If you can set aside a couple of hours for WP:ATODAY, I'd trade you for a couple of hours on this article. Netha's tool works pretty well, and you can ask it to scan 500 health-related articles at a time. WhatamIdoing (talk) 18:34, 25 March 2026 (UTC)

So would referring to an expert panel that was held in 1996 not constitute historical information when it pertains to the definition of a proposed disorder or should the reference to the expert panel be removed or replaced with a more recent opinion from an expert panel or review ? tiredkitty (talk) 17:50, 25 March 2026 (UTC)

That content starts with "In 1996 ...". So assuming the text is okay the source is apt. Bon courage (talk) 18:21, 25 March 2026 (UTC)

That 2004 source supports historical facts, namely that the WHO had a panel in 1996 that said some things. But we need to put the things they said in the context of current scientific consensus.

The Current textbook only appears to address a small part of it ("A panel of the World Health Organization (WHO) recommended that the terms MCS and EI be replaced by idiopathic environmental intolerance (IEI), arguing that use of the word sensitivity may be construed as connoting an allergic cause and that the link between symptoms and exposure is unproven"). We would ideally have an up-to-date source discussing this, so we can be confident that there shouldn't be a sentence saying that the WHO definition is now widely rejected, etc. WhatamIdoing (talk) 18:33, 25 March 2026 (UTC)

Proposal: add legal/disability recognition status (distinct from diagnostic recognition)

Disclosure: I maintain mcsdisability.com, an independent MCS information resource. I'm posting here rather than editing the article directly because of that connection. I'd like editors without a COI to evaluate the sources below and implement any part of this they find due weight for.

The issue: The lead currently states MCS is an "unrecognized and controversial diagnosis." That's sourced and I'm not proposing to change it — it accurately reflects that MCS is not a distinct disease entity in the WHO's ICD-11 and remains disputed among bodies like the AMA and OSHA. But "recognition" is doing double duty in medical articles like this one: diagnostic/nosological recognition (does the entity exist as a validated disease with agreed criteria and mechanism — no, per current sourcing) and legal/disability recognition (do government bodies treat it as a qualifying condition for benefits and accommodation — yes, in specific documented instances, and the article currently doesn't mention this at all outside a brief note on the German ICD-10 index and the 2011–2016 US ICD-10-CM episode).

I'd like to propose two additions, both narrow and separately sourced:

1. A short clarifying sentence in the lead (proposed addition, placed after the existing first paragraph, not replacing anything):

"While MCS is not classified as a distinct disease by the World Health Organization's ICD-11, it is included as a specific diagnostic entity in the national disease classifications of Germany, Austria, Spain, Canada and Japan, and the U.S. Social Security Administration has stipulated that it recognizes MCS as a medically determinable impairment for disability purposes."

2. A new subsection, tentatively titled "Legal and disability recognition," placed after the existing "International Statistical Classification of Diseases" subsection (Society and culture section) since it's closely related territory:

"In the United States, the Social Security Administration does not list MCS among its enumerated impairments, but has stipulated in federal litigation that it recognizes MCS as a medically determinable impairment for Social Security Disability Insurance purposes. Disability determinations involving MCS are made on a case-by-case, functional-limitation basis rather than through diagnosis-specific criteria, consistent with how the Americans with Disabilities Act treats MCS generally. This is separate from, and should not be conflated with, diagnostic recognition: the American Medical Association, the CDC, and the American Academy of Allergy, Asthma and Immunology do not recognize MCS as a distinct physical disorder, and a 2025 qualitative study found that policy and institutional misconceptions about MCS continue to create barriers for affected individuals seeking accommodation in practice.

Outside the United States, MCS is formally included as a distinct diagnostic entity in the national disease classification systems of Germany and Austria (via the German ICD-10-SGB-V index, in use since

2000), Spain (recognized since 2014 under ICD-10 code 78.40), and Japan, which maintains its own clinical diagnostic criteria."

Why I think this clears due-weight and MEDRS concerns: none of this is a biomedical/causation claim (which would need the strictest MEDRS sourcing) — it's a claim about what specific government bodies and legal systems have done, which is closer to WP:RS territory than WP:MEDRS. I've deliberately included the qualitative-misconceptions source and the AMA/CDC/AAAAI non-recognition point in the same subsection so it doesn't read as one-sided — legal recognition in specific instances, continued non-recognition by major US medical bodies, and continued practical difficulty for claimants, are all true at once and I think the section should say so.

One citation above is marked [verify before use] — I have a source characterizing the AMA/CDC/AAAAI position but it's a disability-claims-advice website, not something I'd want to be the sole citation for that sentence on a medical article. If another editor has a stronger secondary source for that specific claim (AMA/CDC/AAAAI not recognizing MCS as a distinct physical disorder), please swap it in; if not, I'd rather the sentence be trimmed than rest on a weak source.

Happy to adjust wording, drop anything editors feel doesn't clear due weight, or hold off entirely if there's a reason this shouldn't move forward. Thanks for reviewing. ~2026-40909-23 (talk) 01:43, 21 July 2026 (UTC)

Thank you for raising this issue, @~2026-40909-23. I am unhappy with the "unrecognized" language because of this potential to confuse scientific recognition as a distinct nosological entity versus whether people have real symptoms that can produce real disability and can therefore receive money from disability insurance programs.

However, GPTZero tells me that your comment is AI-generated (which is against Wikipedia's WP:LLMTALK rules), and AI appears to have made some factual mistakes that make your suggested text essentially useless.

For example, can you provide more information about this "German ICD-10-SGB-V index"? The de:Fünftes Buch Sozialgesetzbuch ("SGB-V") isn't an ICD coding system, and, if the German-language Wikipedia is to be believed, it went into use in 1989, not 2000. The German national adaptation of the ICD-10 coding system is called ICD-10-GM (GM for "German Modification").

Furthermore, Harter says "There is some controversy as to whether the correct ICD-10 code for MCS should be T78.4 (“allergy, unspecified”) or rather code F45.0 (“somatization disorder”). While the DIMDI institute (German Institute for Medical Documentation and Information) codes MCS using code T78.4 in its list of diagnoses 36, MCS is also mentioned in the S3 guidelines “Management of patients with nonspecific, functional and somatoform physical symptoms” ", which for the present purpose is basically a long-winded way of saying that MCS is not a separate diagnosis in Germany, because it's getting lumped under "allergy, unspecified".

Looking at this briefly, I think that what would be possible to put in this article is essentially the opposite of what I think you'd like. Neither Germany nor Austria nor Spain actually recognize MCS as a distinct medical condition, no matter what that old letter from the Austrian government got mis-translated as claiming years ago. People with MCS in those countries are recorded in their system only as having an 'unspecified allergy'. In Germany, the Arbeitsgemeinschaft der Wissenschaftlichen Medizinischen Fachgesellschaften (the highest Germany medical organization in charge of developing practice guidelines) alternatively suggests listing MCS as a functional disorder. WhatamIdoing (talk) 02:46, 21 July 2026 (UTC)