There’s such a variety: asthma, contact rash, hives, sneezing, anaphylactic shock, autoimmune disorders, and who knows what else. And they have to do with the immune system (right?), that provides immunity to viruses and bacteria that would otherwise cause disease.
You can become sensitized or desensitized to an allergen by repeated contact. It depends. Depends on what?
The basic question here is, how to understand allergies in order to manage your life sensibly.
I did do a search on “Allergies” and got 16 pages of threads, and there are a lot of bits and pieces in there. This is one of the more useful. But I’d like to see a once-over in one place if possible, as picking specifics out of that many threads is a struggle.
Let me take a stab at this…
While it does have to do with the immunue system, it’s not the part that deals with viruses and bacteria. That’s a different part of the immune system.
The immune system is a very complex thing, and no one fully understands it. It has cells that are generalists (like white blood cells) that consume all sorts of body “trash” as well as specific things like antibodies. Some antibodies are specialized to fight bacteria, some viruses, some fungus, some other things…
“Classic” allergies involve the IgE antibody. That’s immune globulin E. Yes, there are Ig’s A-D, too - they do other things.
IgE is also involved in fighting off parasites like intestinal worms.
The matter is further complicated by the fact that some non-allergic conditions have symptoms similar or identical to allergies … but aren’t allergies, arising out of some other immune response other than IgE
Let’s look at some of the conditions you mentioned:
asthma - this is currently defined as a type of inflammation of the airways. If this inflamation is caused by allergies, it’s allergic asthma. If it’s caused some sort of chemical or toxin that causes inflammation, then while it’s still asthma, it may have nothing to do with allergies at all.
contact rash - you touch something, you get a rash. Now, that might an allergy to a food, involving IgE in the reaction. You might touch poison ivy (and the rash you get from it is one of the more common allergies, though many people don’t know that). However, you could touch a chemical that causes tissue damage, which then causes an immune response - but one that doesn’t involve IgE and for which allergy medications do little or nothing. It’s still a rash, but it’s not an allergic rash however itchy it might be. These rashes might all be called contact dermatitis, which is doctor talk for “You touched it and it make your skin itchy and irritated”
sneezing - which usually is accompanied by running nose and swelling nasal tissues. Well, snot and sneezing is a major first-line defense of your airways. The snot sort of oozes (or pours) out of the cells to literally wash away bacteria, viruses, fungus, debris, dust, and other nasty stuff, and the sneezing keeps it moving along. Well, a little pollen comes along, your body starts the red alert/battlestations mode going, thinking it’s under attack, and the next thing you know, you need a bucket to catch all the mucus. All an over-reaction, of course. The body is trying to flood out the irritant - which is why treatments include steroid nose sprays - which reduce the sensitivity and lower the immune reactions - and nasal washes, which use saline to literally wash things like pollen out of your nose.
Hives and anaphylactic shock - yes, these are actually somewhat related. Here’s my understanding of what’s going on (docs, feel free to correct me if I misstep): Not all immune system components are in the blood - some are in the lymph system, a network of clear fluid that does connect in some spots to the blood, but is also largely separate. Normally, we only pay attention to it when our “glands” get swollen from infection. Anyhow, in normal life lymph and it’s components are not very noticable, but when you get an infection the lymph system also transports immune components and - please remember this next bit isn’t an exact description, more of a metaphor to avoid lots and lots of jargon and complexity - in order for those components to get into the blood and tissues the vessel walls (blood and lymph both) get a little “leaky”, allowing the fluid, cells, and other chemicals to pass more freely between cells than they would otherwise. This results in swelling, among other things (like itchy). Know how when you have a badly infected cut it gets red, swells up, mabye oozes and itches? OK, that’s the mechanism.
Now, in an allergy, the body thinks it’s under attack. Massive, massive all-over attack. So this reaction occurs all over the body (at least potentially). If it’s a minor thing, you get spots where the leaking-swelling-itchy is localized. Maybe a lot of them. That’s called hives. And they itch. You can also get swelling and leaking in the airways - which can lead to an athmatic reaction with lots of mucus/fluid. In a severe case, so much fluid leaks out of the blood and vessels to fight this “threat” that your blood pressure drops dangerously low and you go into shock. Meanwhile, everything is swelling up (that fluid has to go somewhere). If the interior of your mouth and throat swell enough your breathing is blocked and death can ensue. If so much fluid leaks out of the cells of your lungs that your airways literally fill with fluid you really can drown in your own bodily fluids. If your blood pressure drops too low your heart can’t effectively pump blood (which is already lacking oxygen due to compromised lung function) and your brain dies from lack of oxygen. Or your heart won’t get enough oxygen and will just stop. All of which should make it clear why anaphylactic shock is so damn dangerous and nothing to play around with. If someone starts swelling up, wheezing, itchy, and gets dizzy/lightheaded call 911 immediately because they are headed to deep, deep trouble very quickly.
autoimmune diseases - huh. Well, allergies are “autoimmune” in that these reactions can cause tissue damage, but they aren’t like lupus or rheumatoid arthritis, where the body is actively destroying it’s own tissues. Different antibodies are involved. However, in both cases you have a malfunctioning/oversensitive immune systems. People with allergies are more prone to autoimmune diseases, and vice-versa. So there is a relation there, but they aren’t quite the same thing.
Depends on the person.
Some people have a tendency to become allergic to whatever they’re most exposed to. Others don’t.
Some people can be desensitized to allergens. Some can’t.
Why? Because people are different. There’s no way to test a person to know what category they fall in to, although past medical history can give an indication. For example, in my case I responded very well to desesitization therapy for pollens, so if I develop a new pollen allergy it would make a lot of sense to try desesitization again. However, I’ve known people whose bodies just would not learn to calm down, so trying another course of the therapy just wouldn’t make a whole lot of sense. It could potentially make things worse.
This I’ll have a go at later, as now I have to get my allergic butt to work. Or maybe someone else can have at it.
And remind me to talk about eczema, which is a rash but not always contact rash.
The short version is that your immune system needs to be introduced and exposed to stuff it will encounter later on. Especially at an earlier age, and it seems that the first year is especially important. Hygiene is important for obvious reasons, but too much hygiene sets a baseline/threshold for the immune system that is too low, causing it to too quickly respond to all sorts of stuff. Your immune system is capable of learning throughout practically your whole life, however, so this goes for later ages also.
I can’t back it up with cites atm, but I have always believed that anti-biotics contribute to this. If possible, the body should deal with infections itself, so that its immune system gets a workout. As said, the immune system can learn throughout its whole life to respond to certain agressors (if I recall properly this information I think is partly stored in the liver, where many specific types of T-cells are created depending on the stimulants)
Once you’ve developed allergies anyway, however, it’s important to realise how certain allergens reinforce each other, sometimes very strongly. Cat-allergies and certain pollen allergies, for example, can exist both at a level that you don’t notice individually, but when combined you can get some serious reactions, running eyes and sneezing, etc. This sometimes makes it hard to diagnose the exact cause of an allergy.
Well, I can speak to rashes and such:
Part of the problem with some rashes and other ‘allergic’ reactions is that there is alot that is just not understood. For example, you could develop a reaction or a rash one day to something that you never had a reaction to before.
Also, you could take something and test it on various parts of your body, without trouble. Then, in one area, you get a flare up.
My research does indicate that stress and its effects on the immune system play a vital role in the frequency and the severity of reactions. Additionally, maintaining proper weight (via balanced nutrition) and avoiding rapid losses and gains can keep the immune system stable, minimize stress and suppress flare ups.
But you’ll still find alot of guesses and unanswered questions, because there is much to be understood yet.
My suggestion - and I’m not a doctor, just a long-term allergy sufferer - is that a person with allergies find out what, exactly, they are allergic to as a first step. And that can be harder than you think.
For instance, if a child - let’s call him Timmy - is eating a bowl of raisin bran and suddenly suffers a massive allergic reaction you’re going to want to know what in that bowl set him off. Obviously, you don’t want Timmy eating that again! And the knee-jerk reaction of most doctors (in my experience) is going to be “it’s the milk”. Well, maybe - dairy is a common allergy, but not everyone with allergies is allergic to dairy. It might be the raisins. It might be the wheat. Or, if it’s “multi-grain” raisin bran it might be corn or rice or barley or — You get the idea? You don’t want to ban milk unless it really is the problem. If you pull the wrong thing out his diet he’ll miss out on healthy food and STILL be getting these terrible reactions.
But the first step is to find out what you’re allergic to. The second step is to try to avoid that thing. If you’re allergic to a food, don’t eat it. If a brand of soap gives you a rash, don’t use it. And so forth. Read the labels on everything
Sometimes, you can’t avoid an allergen - such as pollen during the hayfever season. This is when we go to drugs. Mediciations for allergies have improved a great deal in the last 10-20 years or so - more choices and fewer side effects. It may take some experimentation to find out what works best for a particular person. I’d also be wary of doctors who like to over-medicate, because that happened too often to me when I was a kid.
A few people need to take medication on a daily basis to control the reactons. In particular, asthma sufferers may need to take daily medication but, again, the drugs available today have fewer and less severe side effects than those from 50 years ago. Untreated asthma can lead to permanent lung damage - and that is a bad thing. I’ve encountered too many parents who are upset that little Timmy is “on those powerful drugs” - assuming proper diagnosis, Timmy needs those drugs to grow up into a healthy young man and he’s not being a wimp for taking them.
Desensitization is an option for some things, not all. Bee venom, for instance. Pollen. But it only works about 70% of the time, one person in four this will not help. Know that going in. And it doesn’t work for food allergies. Yes, it’s getting poked in the arm, which freaks some parents out - Oooo, but it’s HURTING little Timmy! It’s causing my Precious Child pain! - but they never consider the poor darling is already suffering. I got jabbed four times a week for five years and found that 1) the jab is an insignificant pinprick, far less than a papercut or stubbing my toe and 2) because it worked it was worth every damn jab and 3) if I thought it would help me further I’d get jabbed EIGHT times a week for TEN years because the relief was blissful… once I started seeing an effect. It takes a couple months, or it did for me. I just wish I’d gotten the shots years earlier. Yes, there are a some potential side effects and risks (beyond just a sore arm) - but for the most part it’s managable. MUST be done under a doctor’s supervision.
I’d agree with this - the healthier I am in general, the fewer problems I have. It doesn’t make the allergies go away, just moderates them (but that’s a good thing, too). I’d also like to mention getting enough sleep, which is something our society does not encourage. If I get short on sleep my allergies flare up. Seven to eight hours a night, no cheating.
A little bit more about allergic rashes and food allergies. Food allergies don’t always manifest as wheezing and shock. Sometimes they appear as diarrhea and rashes. The “squirts” and intestinal upset that food allergies can provoke is akin to the runny nose effect - the body is trying to flush out an irritant. And this can cause problems with diagnosis, because so many things can cause diarrhea, and the symptom may appear a day or two after you eat the offending food, which makes identification difficult.
Rashes are a different matter, and maybe not as well understood. The theory I favor is that this allergens that set a person off get absorbed into the blood stream (that’s the point of digestion, after all - to get things from the gut into the rest of the body) and distributed around the body. So a food-allergy induced eczema (that is, rash) might appear 2-3 days after the offending food is eaten, and appear anywhere on the body, or everywhere on the body.
And the food allergy thing can be very difficult to manage. If you’re allergic to, say, corn and start reading food labels you’ll find it’s in just about everything these days, or so it seems. And you can’t have any - even an amount too small to taste can pose risks. Picking it out of soup won’t work - you’ll get the large pieces but not the microscopic ones. Most bagels these days seem to have cornmeal on their bottoms. It’s in multigrain bread. Pringle’s potato chips. And so on.
THEN you have to deal with the nutjobs - the people who say your allergies will be cured if you just accept Jesus into your life, the people who claim it’s the filling in your teeth, the flouride in the water, the phase of the moon… THAT’s as annoying as the physical symptoms.