Allergies Are Becoming More Frequent. Why?

By Adam Collison, Elizabeth Percival, Joerg Mattes, and Rani Bhatia of the University of Newcastle. This story was originally published by The Conversation.

Allergies are reactions caused by the immune system as it responds to environmental substances that are usually harmless to most people. They may occur in response to a range of different material (called allergens), such as food, pollen, dust mites, animals, insect stings, or medicines.

An allergy can affect different parts of the body. Allergic rhinitis, or hay fever, for instance, affects the nose and eyes, while eczema affects the skin. Food allergies affect the gut, skin, airways, lungs, and sometimes the entire body through the blood vessels.

Other conditions such as asthma, which affects the lungs, and eosinophilic oesophagitis, which affects the tube from the throat to the stomach, are closely related to allergy. But they have slightly different underlying causes.

A range of reactions

While most reactions are only mild to moderate in severity (and can be treated with antihistamines), some can be life-threatening and require emergency medical treatment. The most severe, systemic allergic reactions are known as anaphylaxis. People with known severe allergies should have an emergency management plan that includes an adrenaline auto-injector for emergency use.

We can confirm whether someone has an allergy by doing a skin-prick testing or a blood test that checks whether their immune system has produced antibodies to an allergen. If the immune system has developed antibodies, it will remember the allergen as a potential threat and is likely to mount a strong immune response on subsequent exposure.

The likelihood of someone having an allergic reaction from future exposures to the allergen is determined by taking their clinical history and these test results into account.

Allergic rhinitis, or hay fever, affects the nose and eyes. parrchristy/Flickr, CC BY-SA

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