What should you know about allergies causing conjunctivitis?

It is not contagious. Symptoms may appear alongside sneezing, a runny nose or nasal itching, and may flare after contact with pollen, dust mites, mould or animal dander.

Intense itching is a strong clue to an allergic cause. The eyelids can become puffy, tears may be plentiful, and the white of the eye may look pink or red. A thin, watery or stringy discharge can occur, but thick pus-like discharge, eyelids stuck together, or symptoms affecting only one eye may point to another cause.

Eye redness also occurs with infection, dry eye, a trapped foreign object and other eye conditions. An examination is useful when the pattern is unclear, symptoms keep returning, or your usual allergy treatment is not working.

Avoid rubbing your eyes because friction can worsen swelling. Apply a clean, cool compress to closed eyelids, use preservative-free lubricating eye drops if suitable for you, wash your hands after touching pets, and rinse your face after outdoor allergen exposure. Keep windows closed when airborne triggers are troublesome.

Remove contact lenses until the eyes feel normal and any discharge has cleared; use glasses in the meantime. A pharmacist, GP or eye-care professional can advise whether antihistamine or mast-cell-stabilising eye drops suit your symptoms and other medicines. Antibiotics do not treat an allergic reaction, although they may be prescribed if a clinician finds a bacterial infection instead.

Seek urgent assessment for eye pain, reduced or blurred vision that does not clear with blinking, marked light sensitivity, an eye injury, chemical exposure, or the feeling that something is stuck in the eye. These features are not typical of straightforward allergic conjunctivitis.

Contact-lens wearers with a red or painful eye should remove the lens and obtain prompt professional advice because corneal infection needs to be excluded. Arrange a routine appointment if symptoms persist, repeatedly disrupt daily life, or you cannot identify or avoid the trigger.

Ask whether your symptom pattern fits allergy or needs an eye examination, which drops are compatible with contact lenses and existing medicines, how long to use them, and whether recurring episodes suggest a trigger that can be reduced. Mention pain, vision change, light sensitivity, discharge, recent eye injury and every product already tried.