Complaints & connections · borters.ch
Multiple Chemical Sensitivity
The symptoms are real and can narrow daily life considerably; what is open is the path by which they arise.
Also known as: Multiple chemical sensitivity · MCS · idiopathic environmental intolerance · IEI · fragrance intolerance · odour hypersensitivity
Open in the tool — with search and all the links →This compilation is for information and replaces neither medical diagnosis nor treatment. If you have symptoms, see a doctor.
People describe reacting to smells and chemicals in amounts others do not even notice: cleaning products, perfume, fresh paint, exhaust fumes, fabric softener. The symptoms hit several systems at once — headache, nausea, dizziness, exhaustion, trouble concentrating, irritation of eyes and airways, a racing heart. The picture has been described since the 1980s; the summary in common use names six points: a chronic course, reproducible symptoms, triggered by very small amounts, by several chemically unrelated substances, improvement when the triggers fall away, and involvement of several organ systems. These points describe the picture — they do not explain it. The difficulty starts with the name. A number for billing exists: in the German version of the international classification MCS sits under T78.4, a catch-all for “allergy, unspecified”. It has no entry of its own; applications for one have been filed several times and not granted. The major professional bodies do not list MCS as a disease in its own right. An international workshop proposed in 1996 that it be renamed “idiopathic environmental intolerance” — precisely because the word “chemical” asserts a cause that has not been shown. What is well established: in double-blind trials people do react, but not to the substance itself. As soon as it can no longer be told whether the real thing or a sham is presented, symptoms arise equally with both. What is equally true: smells are very hard to mask, and a test chamber does not reproduce a working day. Both objections deserve to be taken seriously. What is not in dispute is the suffering: the limits in daily life — home, workplace, public transport — can be considerable, and frequency figures run from a few per cent to a third, depending on how the question is put. In practice this means two things. First, what produces the same picture and can be treated belongs ruled out: asthma and hay fever, sinuses, thyroid, anaemia, sleep apnoea, migraine, anxiety and panic disorder. Second, treatment follows the symptoms, not an assumed poisoning. Avoiding triggers where it costs little makes sense — but an avoidance that keeps widening narrows life without the sensitivity improving in return.
Asthma, hay fever, sinuses, thyroid, anaemia, sleep apnoea, migraine, anxiety and panic disorder produce the same picture — and each can be treated. That is not distrust, that is the order of things.
Note it for two to three weeks: where, when, how long, what followed — and the days without symptoms too. In hindsight memory always drifts towards the striking days.
Fragrance-free washing and cleaning products, air the rooms well, let new purchases off-gas, raise ventilation at work. That comes at no cost.
Every further avoided situation takes away a piece of daily life without the sensitivity easing. Where the line lies is a personal judgement — it should be made deliberately and not drift on its own.
Of everything in this pattern, sleep has the strongest effect. Regular movement and fixed times lower the overall load, whatever its origin.
In studies it lowers the symptom burden and helps regain daily life. It treats the handling of the symptoms — not their cause, and it does not claim to know it.
Ventilation, choice of desk, fragrance-free cleaning, some days at home — much of this is negotiable and cheaper than an absence. The earlier it is raised, the more is possible.
Giving up visitors, errands and outings loses exactly what lowers the burden. Keeping contact is not a side issue here.
There is no drug for MCS, and detoxification procedures and chelating agents changed nothing in studies — they bring extra burdens for some. What works in studies is aimed not at the substances but at the reaction to them: behavioural therapy over eight to twelve weeks lowers the impairment measurably. Complete avoidance narrows daily life and lowers the threshold further over months — that is the point at which the thing takes on a life of its own.
About twelve to thirty in a hundred people report heightened sensitivity to everyday smells; about one to three in a hundred are markedly limited in daily life. The complaints usually set in within minutes of contact and last hours to days. In blinded provocation tests the reaction occurred just as often when no substance was present — the smell as a trigger was not refuted by that, but the amount in the room was.
Head, airways, stomach, circulation, concentration — not one organ but many at once. That is what sets the picture apart from an allergy.
Amounts others do not notice, far below anything considered toxic. Usually the smell is what registers first.
Perfume, exhaust, paint, cleaning products, printer paper — substances with nothing in common. That fits no allergy either.
On holiday, at the weekend, in another flat it gets better. That points to the surroundings — but says nothing about which part of the surroundings it is.
Shopping, taking the bus, having visitors, working — step by step more falls away. This narrowing is often the heaviest part.
Not proof of MCS. To exclude a true allergy, which causes the same symptoms and is treated differently.
To exclude: a thyroid disorder explains exhaustion, poor concentration and sensitivity to cold or warmth well — and is treatable.
To exclude: iron deficiency causes fatigue, headache and poor concentration, often long before the blood count changes.
To exclude an inflammatory cause. In MCS it is usually unremarkable — which speaks neither for nor against.
A lack causes exhaustion, problems concentrating, low mood and forgetfulness — and it is one of the few causes that can be found and put right with a single blood draw.
Low values are common with low mood. Whether correcting it lifts the mood is not settled; that it makes sense in winter at our latitudes is.
An empty store causes tiredness, lack of drive and problems concentrating long before any anaemia becomes visible. In women of childbearing age the most common single reason.
A building block of the cell coverings in the brain. The studies on mood are inconsistent; as part of a good diet it belongs there anyway.
Needed for making the messengers in the brain. It runs short with alcohol and under certain medicines — and it is always judged together with B12.
In this field a striking amount is sold — detox courses, binders, infusions. For none of them has an effect on the complaints been shown, and some bind in the gut what is needed as well. What is worth it is the simple round: ferritin, vitamin D, B12, thyroid — because the same complaints can come out of those holes and are then fixable.
Very widespread in this setting. They bind in the gut — only they bind unspecifically, so iron, zinc and medicines as well. With daily use over months that is the described harm; a benefit it is not. If at all, then several hours apart from everything else.
Someone who avoids smells and rooms is often outdoors less — and a low level makes tiredness and muscle pain, which is exactly what is there anyway. One of the few measurements here that can really change something.
Clearly worthwhile and well supported when deficient — vegan, older adults, certain drugs. No energy boost without a deficiency.
Clearly effective with proven deficiency, useless without. Take only with a documented deficiency — excess is harmful.
Effects on inflammation and triglycerides established; cardiovascular prevention is mixed. Watch quality and freshness.
In pregnancy clearly established against neural-tube defects, otherwise mainly with deficiency. Can mask a B12 deficiency — watch both.
As with electrosensitivity the complaints are real and, in blinded trials, the triggering is not bound to the substance. That does not make the suffering smaller — it only shifts the question of where help begins.
Before a picture is classed as MCS, the values that cause the same complaints belong checked: thyroid, ferritin, B12. A cause found saves years.
In chemical sensitivity more and more foods are often cut out. That leads to deficiency and increases tension around eating. Anyone cutting should do it in a limited and supported way.
The complaints are real, regardless of the path that leads to them. Methods for coping with stimuli are studied and help some — they do not question the perception.