And that’s only on the outside. Inside, allergens run amok throughout the year, triggering allergy symptoms like coughing, sneezing, stuffy and runny nose — and swollen eyes. Allergies can cause the eyes to swell and become red, itchy, watery,
The reason people have swollen eyes from allergies is they’re getting contact in the eyes from airborne allergies. Basically, what happens is that when the allergens hit your eyes, they sort of dissolve in your tears. They have contact with the lining of the eye [the conjunctiva], and they react with antibodies that are bound to cells in your eyes. These antibodies cause the body to release histamine — which also causes nasal congestion that often accompanies swollen eyes.
The allergens doing this damage include outdoor allergens like pollen and molds and indoor allergens such as cat and dog allergens, and indoor molds.