What Causes Eye Allergies?
An allergy is when the body’s immune system reacts to an allergen that is normally harmless. When an allergen comes in contact with your eye, certain cells within your eye (called mast cells) release histamine and other substances to fight off the allergen. This reaction causes your eyes to become red, itchy and watery.
Allergens in the air — both indoors and out — cause many eye allergies. These allergens include:
- pollen from grass, trees and ragweed
- pet dander
Allergic reactions to perfume, cosmetics or drugs can also cause the eyes to have an allergic response. Some people may be allergic to the preservative chemicals in lubricating eye drops or prescribed eye drops. They should use preservative-free drops instead if possible.
Sometimes, the eyes can react to other allergens that don’t necessarily come in direct contact with the eye. These can include specific foods or insect bites or stings.
Some people inherit eye allergies from their parents. You’re more likely to have allergies if both of your parents have them than if only one does.