Allergies

Allergies occur when your immune system reacts to a foreign substance — such as pollen, bee venom or pet dander - or a food that doesn't cause a reaction in most people. Your immune system produces substances known as antibodies. When you have allergies, your immune system makes antibodies that identify a particular allergen as harmful, even though it isn't. When you come into contact with the allergen, your immune system's reaction can inflame your skin, sinuses, airways or digestive system. Allergies are when your immune system overreacts to something called an allergen. An allergen is a foreign substance that's not harmful to most people, such as pollen or pet dander (skin cells from animals with fur or feathers). But when you have allergies, your immune system tries to fight it off as it would a germ or virus.