Being ‘allergic’ to something or ‘having an allergy‘ is quite common. You might have an allergy yourself or you might know someone who has one.
But what is an allergy and what does it mean to be allergic to something?
An allergy is a kind of illness that happens when your body thinks that something you’ve come into contact with is unusual or dangerous. It causes a biological reponse inside your body that is a bit like what happens when you get an infectious disease. (You might remember I talked about infectious diseases in my previous post on vaccination.)
Allergies have some common symptoms: they might make you sneezy, itchy, wheezy or give you a rash. Usually, these symptoms will go away or get better after a short time, especially if you take some allergy medicine and move away from whatever it is that you are allergic to.
If you have an allergic reaction to something, your body tries to fight off the thing it thinks is dangerous by making cells called antibodies which release a chemical called ‘histamine’ into your blood. The histamine travels around your body and causes the allergy symptoms, like itchiness and sneezing.
There are lots of things that can cause allergy: animals, plants, foods and chemicals. A common allergy is hayfever, which is caused by pollen from trees, grasses and flowers.
If you know you have an allergy, it is a good idea to try to avoid the thing that you are allergic to. That’s because a bad allergic reaction could make you very, very poorly.