[ELI5] Why can we gain resistances to medicine, alcohol, poison, etc. but not so much for allergies or pollutants?
In: 1276
We can gain resistance to allergies. Many people are allergic to cats but they own a cat which they become less allergic to.
Allergy shots work in a similar way by helping your body get used to the allergen. Since it is not a harmful foreign body your immune system learns that it’s not dangerous over time.
We can, we just have to do it over a long time. Starting off with very small doses and working our way up like people who drink a lot do, or people on opiates do. It’s more of a thing of titration (that starting small and moving up), consistent doses and all that.
In fact there’s this girl on tiktok (link [here)](https://vm.tiktok.com/ZML3xnTWV/) that ate a small piece of carrot every day, slowly increasing the amount snd she slowly became less and less allergic.
But in situations where allergens cause a large reaction like anaphylaxis, the potential damage to the body (death, serious injury and bodily damage) out way the positives of being able to eat/be in contact with your allergen.
With severe allergies, and I hope someone corrects me cause I’m not 100% sure on this, each reaction gets increasingly severe. Like the opposite of building a resistance, each time a reaction occurs subsequent reactions will most likely be worse.
Gaining resistance to allergens is definitely possible and is now becoming more and more widespread. The official name for the treatment is Oral Immunotherapy.
I started several years ago, and am now able to eat food containing ingredients I’m allergic to. To get to this stage, you start at a dose of almost nothing, then every few weeks or so slowly increase how much you tolerated. The largest downside is to keep up your immunity you must take a dose of you allergen pretty much every day forever.
All in all, Its amazing stuff. I use to be so allergic that I could react simply off the smallest contamination.
I’ve heard of it being done for: dairy, nuts, tree nuts, peanuts, sesame, and egg, but I’m pretty sure at least my allergies will work with you to set up any allergen you want.
Former football player AJ hawk defeated his shellfish allergy by slowly exposing himself to increasing levels of shellfish over a long period of time
Same reason why you don’t gain resistance to bullets by being slowly exposed to bullets over a long period of time. Take a pollutant like asbestos, it causes cancer because the tiny fibers get stuck in the mesothelium and damage the surrounding cells. You can’t immunize to that, it is a structural issue. The more exposure to asbestos (or lead or UV radiation or whatever) you have the worse it is for you – period and end of story. The body is a giant chemistry experiment held up by a lego set, you can adjust the chemistry (so medicines, poisons etc) gently but if you tear apart the legos you are just left with a pile of junk.
Poisons, toxins, and allergens are a fundamentally different thing. They don’t damage, as such, the structure of the body as much as they interrupt biological processes or similar. The body *can* adjust to that over time.
A lot of it has to do with chemistry and biology.
Your immune system, oversimplified, can be trained to recognize bacteria and viruses and create cells capable of killing them. This is a complicated dance between if it notices, when it notices, and how fast it can produce germ-killing cells vs. how fast the “invader” can reproduce. This can get complicated when the “invader” evolves around this and/or can infect your immune cells. For example, that’s behind the “cytokine storm” deaths you’d hear about from COVID: it’s capable of damaging your immune system to the point where your immune system attacks *your body* and that’s not a great situation.
Allergies, as best as we can tell, are a glitch in your immune system. It sees some random trigger like cat dander and for some reason some peoples’ immune systems see that as a major threat. So it rallies a ton of germ-killing cells and… well, cat dander isn’t really a bacteria or virus so it’s not exactly effective. The immune response can cause tissue to become inflamed, which leads to a lot of other symptoms and worse, if it happens in the tissues around your airways you start having symptoms of asthma and other bad things.
We can sort of build tolerances to some things that cause allergies (“allergens”). A lot of people get allergy shots, which is literally injecting them with the things they are allergic to in very careful doses. Sometimes if this happens enough, the immune system starts to decide maybe those things aren’t invaders after all and it stops responding so strongly. This can be a dangerous game, and if someone is severely allergic to something it’s not possible. (For example, some people are so allergic to peanuts just breathing some dust can kill them. There’s just not a “safe” dose for them. I’ve had full-blown asthma attacks in response to allergy shots on multiple occasions.)
Same thing with alcohol, we only get half-resistant to it. Alcohol does two things: one is it changes how your body produces a lot of chemicals which is what causes you to get drunk, the other is processing it can cause some damage to your liver and some other organs. The way the body works, if you drink frequently then the systems that produce and detect your body chemicals will change, and you’ll be less likely to get drunk from the same amounts of alcohol (within reason.) But it never stops doing damage to your organs and if you drink more to get more drunk you do even more damage.
The poisons we can tolerate fall under that umbrella: they do some kind of physical damage to your organs, but maybe mess with some other chemicals. If your body adjusts those chemical systems, you won’t feel the bad effects of the poison as much, but if it was doing physical damage there’s not much you can do about it.
The extreme case of that is supposing you drink a really caustic acid. That is something that chemically destroys your cell membranes and burns tissue. You can’t really “build up” your cell membranes to resist it. It’s like trying to say, “I want to build a tolerance to lava”. There are some situations you just can’t make your body get used to.
Some poisons work by just getting in the way of how important things work. Like they might cause a chemical change in nerves that makes them unable to transmit signals, and if they do that to the nerves that control your heart it will stop. You can’t build a tolerance to this because there’s often a chemistry and physics explanation for why your body can’t do things another way or put up with “less” of something.
For example, carbon monoxide. Your red blood cells work because they have a structure that is very “sticky” to oxygen molecules. What they really want to pull out of the air is “O^2” or what we call pure oxygen. That’s 2 oxygen atoms bonded together. The body wants that because we have chemical processes that can break O^2 down into its atoms and use them. Carbon Monoxide is “CO”, one carbon atom bonded with one oxygen atom. Because of its shape, it’s ALSO “sticky” to the red blood cells. But because of the way carbon bonds with oxygen, your cells can’t break it apart and use the oxygen. In fact, they have a hard time getting the blood cells to let go of CO! So more and more CO sticks to your red blood cells over time, which means you’re getting less oxygen from the air, and eventually no matter how deep a breath you take your body can’t get any usable oxygen from the air and you die.
There’s no way to build a tolerance to that. It’s chemistry. We’d have to have red blood cells that somehow reject bonds with CO molecules, but for chemistry/physics reasons that’s not really possible.
So this is a really complicated question and the answer boils down to: “We can’t always build a tolerance to things. The body isn’t a video game character where everything that doesn’t kill us makes us stronger. Some things, like HIV and COVID-19, don’t kill us directly but make us significantly weaker and more likely to die from other things by screwing up the systems that would help us build tolerances.”
Because allergies are caused by your body being over reactive and not from an external source.
It varies according to the thing you are exposed to for example ethyl alcohol is an organic chemical compound meaning it is carbon based, part of the branch of chemistry that describes living things. Ethyl alcohol is created by certain bacteria living in your stomach and some amount passes into your blood stream naturally.
Many industrial pollutants are not organic compounds and are instead composed of heavy metal compounds. These compounds have a tendency to interact with the body in much more permanent way. Often when compounds like these get into the body there isn’t any way for the body to move them across the various membranes to be expelled as waste. This build up means the body cannot become more efficient at expelling the whatever.
So yeah, the more natural a thing is to your body the more you’ll be able to develop a resistance to it.
As other people have said, it is actually possible to gain resistance to allergens. Doctors tend to recommend it most often for severe allergies or if their patient is at risk for developing asthma. The most commonly used medical method are allergy shots. I spent most of high school years getting weekly allergy shots because I fell into the second category.
That being said, though, I want to correct another slight misconception in this question. Building tolerance to drugs are temporary, not permanent; as in, they only lasts if you’re taking the drug on a regular basis.
And that can be quite dangerous because if someone has withdrawn from a drug for a long enough period of time and then goes back to it, they are likely to take it at the higher dose they were used to back when they were using regularly and [then overdose and die](https://time.com/5350490/demi-lovato-drug-relapse-dangers/?amp=true). The fatal overdoses of Whitney Houston, Peaches Geldof, Cory Monteith, Sid Vicious, Wayne Static, Dwayne Goettel, and Philip Seymour Hoffman were probably caused in part by this phenomenon.
Latest Answers