What are allergies?

Allergies are your body’s natural response to certain medications or substances (allergens) such as pollen or dust mites that it doesn’t recognise^1^. This response may lead to itchy skin, a runny nose, or red, itchy eyes, among other symptoms^1^. Your allergy might occur during particular seasons of the year, or year round, depending on the cause.


When your body comes into contact with an allergen, this triggers the release of histamine from mast cells, resulting in an allergic response^1^. Mast cells are found in the tissues that are in contact with the external environment, such as the eyes, nose, mouth, throat and skin^1^. So when pollen, for example, lands on the eye, mast cells identify it as an intruder, producing histamine, which then leads to allergy symptoms^1^.
Common allergens affecting the eyes include, but are not limited to, pollen, ragweed, grass, moulds, weeds, dust and pet dander^2^.



1. Allergy UK. (2012) What is an allergy? Available at: [] 
2. Allergy UK. (2013) What is causing your allergy? Available at: [] 
3. American College of Allergy, Asthma & Immunology (2014) Allergy Medication. Available at []
4. WebMD. Mast Cell Inhibitors for Allergy Symptoms. (2016) Available at: []


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