My OH runs from one allergic sinusitis and otitis into the next when she is at home in the Midwest of the USA, very bad bouts that practically paralyze her for weeks, with intermissions of only two or three weeks between two spells. As soon as she flies to Switzerland, she's fine. There may be the odd sniffle once in a few months, but only a small fraction of what she suffers in Michigan.

In other words, it's not the country or whatever, it's the kind of allergies you have.

Yes, of course this is true! However, I find it strange/interesting/annoying that after 10 years of doing BEST in Switzerland, I'm now doing worst here .

Annoying yes, but not strange. An allergy always is something you acquire. You are not born with it. You need some previous contact with the allergen, "some" meaning anything between "once" and "several decades," depending on many factors. So it's not unusual to develop an allergy after 10 years of having been exposed to an allergen.

Not disagreeing...in case my tone gets lost in internet translation, but...

Why then does immunotherapy (at the doctor's office) make things better? I would think my repeated exposures to whatever Swiss allergens is bothering me would actually make it better.

I would like to point out that many people go to switzerland for the clean air to recover from such ailments. I dont think your allergic to swiss nature although if you live outside of the cities you could be getting hay fever

Immunotherapy (in this case suppression immunotherapy, a.k.a. desensitization) usually consists of a carefully calculated increasing exposure of the immune system to the allergen(s) in question in order to make the immune system adjust to the allergen, thus reducing or eliminating an immune response in case the body gets into touch with the allergen in the wild. (Now that was a long sentence....)

The essential thing is the increasing dosage over a long period of time. Recurrent exposure of random periodocity, random intensity and random duration, as occurring in the wild, is not the same. It makes the immune system jump from zero to full throttle and back, without giving it a chance to get used to the allergen.

You can get hayfever even in the middle of Chicago. Airborne pollen travels over dozens, often even hundreds of kilometers.

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