Can allergies cause itchy eyes?

How allergies cause it

The itch of an eye allergy starts in the conjunctiva, the membrane that covers the white of the eye and the inner side of the eyelid.³ When the immune system identifies an otherwise harmless substance as an allergen, it makes antibodies called immunoglobulin E (IgE).³ In the eye, the allergen comes in contact with antibodies attached to mast cells, and the cells release histamine and other chemicals that cause tiny blood vessels to leak and the eyes to become itchy, red and watery.² Symptoms usually appear soon after the eyes come in contact with the allergen.⁴

Itching is a hallmark sign of eye allergy.¹ It can be intense.⁷ Seasonal eye allergy symptoms include itching, redness, burning and a clear, watery discharge, and eye symptoms usually accompany the sneezing, sniffling or stuffy nose of nasal allergies, though they can also occur on their own.² The itch may be so bothersome that people rub their eyes often, which makes the symptoms worse.²

Seasonal allergic conjunctivitis is by far the most common type, and its symptoms come in spring, summer or fall, depending on the type of plant pollens in the air.² Indoor allergens such as dust mites and pet dander can cause eye allergies year-round, and you may notice your symptoms get worse while cleaning the house or grooming a pet.³ Vernal keratoconjunctivitis, a more serious eye allergy that mainly affects boys and young men, can impair vision if left untreated; atopic keratoconjunctivitis, which mainly affects older people, mostly men with a history of allergic dermatitis, can scar the cornea if left untreated.²

Allergies or something else?

Allergies usually cause redness and itching in both eyes, not just one.⁵

Pink eye from other causes can look similar, because pink eye of any kind can turn the white of the eye pink or red and make it itch.⁷ Viral pink eye can come with a cold, flu or respiratory infection and usually starts in one eye, spreading to the other within days.⁷ Bacterial pink eye usually produces thick pus that can make the eyelids stick together.⁷ Unlike pink eye, symptoms caused by an eye allergy are not contagious.⁴

Other conditions overlap with eye allergy, such as infections and dry eye, which can make it hard to arrive at the right diagnosis.¹ Because eye allergies share symptoms with some other eye diseases, an accurate diagnosis matters.²

When to see a doctor

Pink eye can affect vision, and CDC advises seeing a healthcare provider for eye pain, light sensitivity, blurred vision or intense eye redness.⁷

An allergist has the training to find out which allergens are causing your symptoms.³ Tests can include a microscopic exam of the eye and a gentle scraping of the conjunctiva to look for a certain type of white blood cell.²