Sometimes the system goes wrong, and is triggered by some quite normal food, or flares up when the family pet comes into the room. That is what the ordinary person calls an 'allergy'.
When people come in contact with something they are allergic to, there can be many different reactions. Their eyes may become very itchy, and their noses may become drippy or stuffy. They may cough and sneeze. They may develop a rash called hives. Their faces may swell up. If it is a food allergy, the person may get an upset stomach.
Sometimes a person's oesophagus, or throat, may swell up so much that the person can no longer breathe. This is called anaphylaxis. When this happens, a doctor must give the person a medicine called epinephrine to make the swelling go down. Some people with allergies to very common things, like bee stings or fish, carry this medicine with them so it can be used quickly in an emergency. The device they use to inject the medicine is called an epinephrine autoinjector.
Some common food allergies are:
- Nuts, especially peanuts
- Fish or shellfish
- Dairy products
- Soy products
- Fruits (kiwis and bananas)
Some common environmental allergies are:
- "Are you aware of your allergic symptoms?". Retrieved 28 November 2007.