Allergy means ‘change in activity’. It also known as hypersensitive reaction and happens when body defense system reacts to foreign substance that enters the body through the skin, lung, swallowed or pricked skin. This reaction does not need to happen everyone. It happened more often to those who have family’s history who suffered allergy. Common allergic reactions include eczema, hives, hay fever, asthma attacks, food allergies, and reactions to the venom of stinging insects such as wasps and bees.