An allergy is something which triggers an allergic reaction. This is the immune system defending the body against attack by bacteria and viruses.
Sometimes the system goes wrong, and is triggered by some quite normal food, or flares up when the family pet comes into the room. This 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. These reactions include itchy eyes, drippy or stuffy noses, swollen faces, hives, sneezing, and coughing. 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.