Question: What causes allergies?

Alex Evans answered on 16 Mar 2017:

Allergies are caused by our bodies becoming sensitive to something and reacting to it as if it was bad for us – even if it’s not!

This is mainly caused by our immune system making antibodies that respond to ‘allergens’ that can come from all sorts of places like pollen, pet hair or food. These antibodies then trigger an immune response that can include the release of chemicals that cause symptoms including itchiness and swelling – which can sometimes be life-threatening!