Writing about smell will get you thing about nuisance odors and about folks who think that smells are making them sick. A lot of this has to do with allergies, and allergies can be a tricky thing. There is no threshold for the amount of a thing that will elicit a reaction, and so allergies tend to be modulated by our own minds, at least to some extent. In other words, if you’re stressed, or if you’re thinking way too much about these allergies and their allergens and the environment where they come from, you may amplify the effects, and you may start sneezing or scratching at the most miniscule of exposures.
The way allergies work in the body is pretty damn confusing. There’s different kinds of allergies, some are hardwired, we might say, and some are ‘learned’ by the body. Some allergies can be deadly, like a shellfish allergy that closes your throat. Some can be just annoying, but won’t kill you or send you to the hospital (unless your body gets so hijacked by your own histamines that you smash your head into a wall).
All this being said, when I came across this short explanation on how allergies work, and I found it to be somewhat comprehendible, I thought I should repeat it here.
Most chemicals and their metabolic products are not sufficiently large enough to be recognized by the immune system as a foreign substance and thus must first combine with an endogenous protein [something that comes from inside the body not outside, endo- vs exo-] to form an antigen (or immunogen). Such a molecule is called a hapten. The hapten-protein complex (antigen) is then capable of eliciting the formation of antibodies. Subsequent exposure to the chemical results in an antingen-antibody interaction, which provokes the typical manifestations of allergy that range in severity from minor skin disturbance to fatal anaphylactic shock.
-Essentials of Toxicology, Casarett and Doull
Got all that? The “allergic reaction” is really an antigen-antibody reaction. It is your body fighting an intruder, and you are the collateral damage.
Please take a look at another post called “The Dangers of Smell and Perfumes in the Workplace” (forthcoming), but it’s based on this article: perfume in the workplace, which is an interesting look inside the work of an HR worker who has to deal with employees complaining about their smelly coworkers, and soothing the hypersensitive worker who thinks their coworker’s perfume is making them sick (it’s not; unfortunately, it’s your own mind doing that).