How do young kids become allergic to stuff?

Question

Hi all! I work in a daycare/preschool center and a few of our kiddos, even our infants and toddlers have an allergy (eggs, dairy, etc.)

What I’m curious about is how they can be so young and already be allergic to something? You could say it’s because of their environment.. but at that age they are either at home or at daycare. How exactly do they get exposed? And how does our body know certain foods or substances are dangerous?

Please and thank you!

In: Biology

Answer 1

Allergies are caused by our immune system responding to non-dangerous substances as if they were actually very dangerous. This means that sometimes you can develop an allergy after repeated exposure to something (though in some cases you can actually build up a tolerance after repeated exposure), but it also means that it can happen spontaneously or be caused by genetic factors.

To simplify things somewhat, your immune system makes a type of immune cell called a B Cell. B Cells only have one job: they make antibodies. An antibody is a protein shaped a bit like a fork, where the tip of the fork will recognize and bind to one specific type of thing, be it the outside of a virus or a bacteria, or something that is normally benign like peanut oil. Your body is constantly producing new B Cells, each of which makes just one type of completely unique antibody that recognizes something totally random. B Cells that recognize things your body naturally produces are killed off (and if they aren’t you can develop an autoimmune disease), but the rest are simply released into your body to maybe someday meet their specific target and start the larger process of an immune response.

For an ordinary person, when their immune system detects something like peanuts, it will quickly recognize that there isn’t a danger. But sometimes your immune system can get confused, and think that something terrible is happening. When this happens your body tries to fight off the ‘invader’ by rushing a lot of blood to the area (which brings things like white blood cells and other types of immune cells), which causes swelling. If this happens in your throat, it can cause breathing problems, but if it happens somewhere else like your skin it can cause a large itchy rash or other similar symptoms.