eli5: why do humans have allergies (hay fever, pollen, etc)


eli5: why do humans have allergies (hay fever, pollen, etc)

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Imagine a fire alarm system but for when it smells like Bread in the building, or when it smells like bacon, or carbon monoxide.

Alergies are your body reacting to what it sees as a poison danger. The good this is that it shows that it works agressively, the problem is it reacts agressively to the wrong substances.

So the reason it has not been taken out is that it is not a condition that can keep someone from living and have kids (if they are lucky and careful with their exposure once they know.)

Allergies are hypersensitivity of the immune system to the substances. Typically, early exposure to the allergens helps avoid them, and common therapy includes exposing the body to very small doses of the allergens hoping for the body to get used to it without the overresponse.
As for why this happens, well, it’s a body disorder similar to other ones

The body’s immune system thinks that something harmless is actually a dangerous germ and tries to attack it. As with any war, there is some collateral damage, which is why you feel yucky or might even die, depending on the allergy.

The immune system needs “practice”, especially at a young age, at recognizing bad stuff. It is believed that immune systems that don’t get enough practice are more likely to “freak out” at harmless stuff.

One issue specifically with hay fever is that we’ve establishes a policy in cities of planting males trees (dioecious male) that don’t bear fruit that would need to be cleaned up very often. Instead we’ve surrounded ourselves with many, many, many very lonely pollen producers.

Another issue is with our increased use of anti-inflammatories. Most Over The Counter anti-inflammatories are COX / COX-2 inhibitors. A side effect of these inhibitors is that they halt the production of mucus for the protection and proper functioning of your stomach and intestines. Overuse leads to Leaky Gut Syndrome where food particles that aren’t normally absorbed can now enter the blood stream directly which can then cause an immune response and long term oversensitivity.