Written for Stock My Medicine and clinically reviewed by Hajra Dhanchora, MPharm (GPhC 2216990).
A red, gritty, watering eye that's glued shut in the morning is one of the commonest reasons people walk into a pharmacy, and most of the time it's conjunctivitis, inflammation of the thin membrane over the white of the eye. The useful question isn't "what is it" but "which kind", because the three kinds spread, last and respond differently.
What causes conjunctivitis?
Viral, usually with or after a cold: watery discharge, often both eyes, very red, sometimes a tender lump in front of the ear. Bacterial: thick yellow or green discharge, lashes stuck together on waking, often starting in one eye and spreading to the other. Allergic: itchy above all, both eyes, watery, with sneezing and a runny nose, in pollen season or around a cat. Irritants such as chlorine and smoke cause a short-lived version too.
Is conjunctivitis contagious?
Viral and bacterial conjunctivitis are, very; allergic isn't. It spreads on fingers, towels, pillowcases and make-up, for as long as the eye is producing discharge. Wash hands after touching the eye, use a separate towel, bin the mascara, and don't share eye drops. Children do not need to be kept off school or nursery under UK public health guidance unless there's an outbreak, though nurseries sometimes have their own rules.
How long does conjunctivitis last?
Viral: one to two weeks, sometimes three, and it gets worse before it gets better. Bacterial: usually clears within a week on its own, faster with antibiotic drops. Allergic: as long as the trigger is around. Yes, most conjunctivitis goes away on its own; treatment is about comfort, speed and stopping it spreading.
How to treat conjunctivitis at home
Clean the lids with cooled boiled water on cotton wool, one piece per wipe, from the nose outwards. Cool compresses ease the grittiness; lubricating eye drops help a viral eye feel less raw. Leave contact lenses out until it's completely better, and for 24 hours after any drops. Wash pillowcases and towels on a hot wash, and throw away any eye make-up or lenses used since the eye went red; both are common reasons it comes straight back a week later. For allergic conjunctivitis, an antihistamine eye drop or tablet is the treatment; our hay fever guide covers the choice.
When antibiotic eye drops help
For bacterial conjunctivitis with obvious discharge, chloramphenicol drops or ointment from the pharmacy shorten it by a day or two and cut the spread. They're for adults and children over 2, after a short questionnaire: Optrex Infected Eyes and Brolene Antibiotic as drops, Golden Eye ointment for overnight cover. It's a five-day course, finished even once the eye looks clear. For a milder, early infection, an antiseptic propamidine drop such as Brolene Eye Drops is the antibiotic-free first step. Antibiotics do nothing for viral or allergic conjunctivitis, which is why a pharmacist asks about the discharge first. The eye care range is here.
When a red eye needs a doctor
Conjunctivitis is uncomfortable but not painful and doesn't affect vision. See a pharmacist, optician or GP the same day for eye pain, sensitivity to light, blurred or reduced vision, a very red patch, or a feeling that something is in the eye; these can mean something more serious than conjunctivitis. A newborn with a sticky eye in the first month needs a GP promptly, contact lens wearers with a red eye should stop wearing lenses and get checked, and anything not improving after two days of antibiotic drops, or a week overall, needs a look. Our pharmacist can help you decide.
Conjunctivitis in babies and children
A newborn with a sticky, watering eye usually has a blocked tear duct, not conjunctivitis: the eye is white rather than red, and gentle massage and cleaning clear it over the first months. A red, sticky eye in a baby under a month old needs a GP promptly, because some newborn infections are serious. In toddlers and children, conjunctivitis spreads through nurseries on hands and toys; clean the eyes with cooled boiled water, wash hands before and after, and give each child their own towel and flannel. Chloramphenicol drops and ointment are licensed from age 2, and a pharmacist can supply them after a few questions; under-2s go to the GP.
Allergic conjunctivitis: how to tell and treat it
If the main complaint is itching, both eyes are involved, the discharge is watery, and it comes with sneezing or a runny nose, it's allergic, not infectious. Antibiotic drops won't help. Antihistamine eye drops calm the itch within minutes, sodium cromoglicate drops used four times a day prevent it, a cool compress soothes, and an oral antihistamine treats the nose at the same time. Avoid rubbing, which releases more histamine, and keep windows closed on high-pollen days. Our hay fever guide covers the choices.
Contact lens wearers
A red eye in a contact lens wearer is treated as an emergency until proved otherwise, because lenses can trap bacteria that damage the cornea. Take the lenses out, don't put them back in until the eye has been clear for at least 24 hours after finishing any drops, throw away the current pair, and see an optician or GP the same day if there's pain, light sensitivity or blurred vision. Clean or replace the lens case as well.
How to put in eye drops properly
Wash your hands. Tilt the head back, pull the lower lid down with a finger to make a pocket, look up, and squeeze one drop into the pocket without the dropper touching the eye or lashes. Close the eye gently for a minute, pressing lightly on the inner corner by the nose so the drop stays in the eye rather than draining into the throat. Wipe away any excess. For a child, lie them down with eyes closed and put the drop in the inner corner; when they open the eye it runs in. Ointment goes as a small ribbon inside the lower lid at bedtime.
Stopping it spreading at home
Wash hands every time you touch the eye, use a fresh tissue or cotton pad per wipe and bin it, change pillowcases and towels daily until it's cleared, don't share make-up, and discard eye make-up used since it started. The infectious period lasts as long as the eye is producing discharge, typically a few days into treatment.
Frequently asked questions
Can I use chloramphenicol drops on my child?
From age 2, for bacterial conjunctivitis. Under-2s need a GP, and a baby under a month with a sticky eye needs one promptly.
Should I stay off work?
Not usually. Wash your hands often, don't share towels, and avoid rubbing the eye. Close-contact jobs with vulnerable people may have their own rules.
Why does my conjunctivitis keep coming back?
Reinfection from make-up, lenses or towels; blepharitis, an inflammation of the lid margins that needs daily lid cleaning; or an allergy nobody has identified. A GP or optician can sort out which.