An allergy is when your immune system reacts to something that is harmless to most people. This might be chemicals from foods (peanuts, shellfish, nuts, eggs, wheat); animals (dogs, cats); and other materials (grasses, dust, dust mites, medicines).
When the substance enters the body, an allergic reaction occurs. For most people, the allergic reaction is hay fever (runny nose and itchy eyes) or hives (a bumpy skin rash). In some people this reaction is severe and causes anaphylaxis, which is an emergency needing immediate injection with adrenaline from an adrenalin autoinjector. If you think someone is having an anaphylaxis, give them adrenalin if it is available and call an ambulance on triple zero (000) right away.
The Australasian Society of Clinical Immunology and Allergy (ASCIA) recommends that for a severe allergic reaction adrenaline is the initial treatment. For further information, visit the Choosing Wisely Australia website.
Allergies can be treated with antihistamine medicines, and allergy tests might find the cause of the hypersensitivity. If so, it may be possible to have regular injections of small amounts of what you react to in order to stop the body overreacting.
ASCIA also recommends that you should speak to your doctor or specialist about the benefits and safety of allergen immunotherapy or before attempting any allergy testing or treatment. For further information, visit the Choosing Wisely Australia website.
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Last reviewed: February 2020