One Eye Allergic Conjunctivitis: What to Know

Allergic conjunctivitis happens when the surface of the eye reacts to an irritant or allergen such as dust, pollen, mould or animal dander. It commonly produces prominent itching, watery discharge, puffy lids and redness. One eye may be affected first, especially after rubbing the eye or touching it after contact with an allergen; the other eye can become involved later. Thick discharge, marked tenderness, light sensitivity or reduced vision is less typical of a simple allergy. A blocked tear duct, a foreign body, dry eye, or infectious conjunctivitis can look similar.

Avoid rubbing the eye and wash your hands before touching your face. A cool, clean compress over closed eyelids can ease itching and swelling. Reduce exposure to the suspected trigger and keep windows closed when outdoor allergens are high. Do not share towels, cosmetics or eye drops. Remove contact lenses until the eye feels normal and discard eye makeup used during the episode. A pharmacist or clinician can advise whether an appropriate allergy medicine or lubricating drop is suitable; do not use someone else’s prescription drops. If episodes recur, discuss allergy testing to identify useful avoidance steps.

Arrange prompt assessment if pain, strong light sensitivity, blurred or reduced vision, a sensation that something is stuck, or increasing swelling develops. Seek urgent eye care after an injury, chemical splash, or if the pupil looks unusual. Contact a clinician when discharge becomes thick, the eyelids stick together, symptoms spread, or redness does not settle after removing the suspected trigger. Contact-lens wearers should be assessed promptly for a painful red eye because the cornea may be involved.

Could this be allergic conjunctivitis, infection, dry eye or a foreign body? Which features would mean I need an eye examination? Is an allergy medicine or lubricating drop suitable for me? Should I have allergy testing if this keeps returning?