How common is red eye in allergic conjunctivitis?

Allergic conjunctivitis happens when the clear membrane over the white of the eye and inside the eyelids reacts to an allergen. Both eyes are often affected, with itching, watering, puffiness, burning, or stringy mucus. Rubbing can make redness and swelling more noticeable. Red eye has several possible causes, including infection, dryness, a foreign body, injury, or inflammation inside the eye, so redness alone cannot establish an allergy as the cause.

Avoid rubbing your eyes and wash hands after being outdoors or handling a likely trigger. A clean cool compress over closed eyelids can soothe itching and swelling. If you wear contact lenses, stop wearing them while the eye is red or uncomfortable until a clinician or optician advises that it is safe to restart. A pharmacist can suggest suitable lubricating or allergy eye drops and explain how to use them without contaminating the bottle tip.

Get urgent eye assessment for eye pain, sensitivity to light, reduced or changed vision, a severe headache with nausea, injury, a chemical splash, or a pupil that looks unusual. Seek prompt clinical advice if there is thick discharge, eyelids stuck together, symptoms in only one eye that persist, or no improvement after avoiding triggers. Contact-lens wearers with a painful red eye should be assessed promptly.

Ask whether your symptoms fit an allergy pattern, which drops are compatible with your contact lenses, and whether you should be checked for infection or dry eye. Tell the clinician about seasonal timing, new cosmetics or eye products, and any vision symptoms.