Allergies are very common and increasing in Australia and New Zealand, affecting around 1 in 5 people at some time in their lives. There are many different causes of allergy and symptoms vary from mild to potentially life threatening. Allergy is also one of the major factors associated with the cause and persistence of asthma. Effective prevention and treatment options are available for most allergies. Allergy - a definition Allergy occurs when a person's immune system reacts to substances in the environment that are harmless for most people. These substances are known as allergens and a