I could not explain this to you in medical terms, nor is that the objective but what I can say is that an allergy is an overreaction of the immune system to certain organisms such as plants, animals and even the environment.
Call it as a horror film that there are people that can get to see without any reaction and others can not even sleep for a few knights of fear.
The body is so wonderful that tries to heal by itself or respond automatically to counteract everything that hurts us, this function of the body is what is known as the immune system, the body’s ability to try to remove itself of all bad things that happen in the body.
Dust mites, pollen from certain plants, the hair of some animals, are agents outside the human body.
There are people to whom this kind of thing does not really affect them. As their immune system perceives them as something simple to discard.
It was a film X, but allergic people have an exaggerated response to this sort of thing. It is like who are shaking form the horror film. The effect of these agents is so great that the body works like crazy trying to dispose of them.
That’s why vaccines are a good way to eliminate allergies because they do is introduce gradually into the body to which all that overreacts to it will identify as something that can easily be discarded.
Say it’s like therapy for you to watch horror movies without being removed sleep.