Our immune systems help us to keep healthy by protecting us from germs and other foreign bodies that could harm us. But some people's immune systems don't work the same as others. In these people, when their bodies detect something that is normally harmless, their immune system overreacts. An allergic reaction can take many different forms. It may affect the skin, the ears, nose, throat and lungs and even digestion.

What is an allergic reaction?
Last updated: 2019.05.08