Conjunctivitis or pink eye

Conjunctivitis, commonly called pink eye, is inflammation of the conjunctiva. This is the thin, clear membrane covering the white part of your eye and the inside of your eyelids.

Inflamed blood vessels make the eye look pink or red. The eye may water, itch, burn, feel gritty, or produce a sticky discharge.

Conjunctivitis has several causes. Viruses and bacteria can cause infectious conjunctivitis. Allergies, chemicals, smoke, contact lenses, and other irritants can cause non-infectious forms. Treatment and the chance of spreading it depend on the cause.

Most cases are mild and clear without lasting damage. However, a red eye is not always conjunctivitis. Pain, sensitivity to light, reduced vision, or redness in someone who wears contact lenses can point to a more serious problem involving the cornea, the clear front surface of the eye.

Conjunctivitis may affect one eye or both. An infection sometimes begins in one eye before spreading to the other.

Common symptoms include:

• Pink or red eyes
• Watery, sticky, or pus-like discharge
• Itching, burning, or a gritty feeling
• Crusting around the eyelashes, especially after sleep
• Mild eyelid swelling
• More tears than usual

The pattern can give clues to the cause, but symptoms alone cannot always tell viral and bacterial conjunctivitis apart.

Viral conjunctivitis usually causes watery discharge and may occur with a cold, sore throat, or swollen glands near the ear. It often spreads from one eye to the other.

Bacterial conjunctivitis is more likely to produce thick yellow, white, or green discharge. The eyelids may stick together. However, discharge colour does not confirm that bacteria are responsible.

Allergic conjunctivitis usually affects both eyes. Intense itching is common, along with watering, sneezing, or a runny nose. It is not contagious.

Pain inside the eye, strong sensitivity to light, or vision that remains blurred after blinking is not typical of simple conjunctivitis. These symptoms need prompt medical assessment.

Viruses are a common cause. Adenoviruses, which also cause respiratory infections, are particularly associated with pink eye. Viral conjunctivitis can spread easily through hands, shared objects, and close contact.

Bacteria can also infect the conjunctiva. Some bacterial infections are mild, while others need prompt treatment. Gonorrhoea and chlamydia can cause conjunctivitis through sexual exposure or during childbirth. Gonococcal infection can progress quickly and threaten the cornea.

Allergic conjunctivitis happens when the immune system reacts to a trigger such as pollen, animal dander, dust mites, or mould. Symptoms may be seasonal or continue while exposure lasts.

Smoke, chlorine, air pollution, cosmetics, and other irritants can inflame the conjunctiva. A chemical splash is different from mild irritation and requires immediate rinsing and emergency advice.

Your risk of infectious conjunctivitis may be higher if you have close contact with someone who has it, touch your eyes without washing your hands, or share towels, cosmetics, or eye products.

Contact lens wear increases concern because bacteria can infect the cornea as well as the conjunctiva. Sleeping in lenses, using poor cleaning practices, or exposing lenses to water can increase this risk.

Dry eye, inflamed eyelids, and some immune conditions may cause ongoing redness that resembles conjunctivitis.

A healthcare professional can often diagnose conjunctivitis by asking about your symptoms and examining your eyes. They may check your vision, eyelids, pupils, discharge, and the pattern of redness.

A slit lamp is a microscope with a bright light that allows a closer examination of the eye. Fluorescein, a temporary orange dye, may be used to reveal damage to the cornea.

Laboratory testing is not needed for most mild cases. A sample of discharge may be tested when symptoms are severe, keep returning, do not respond to treatment, or suggest gonorrhoea, chlamydia, or another unusual infection. Testing may also be considered for newborns and people with reduced immune function.

Other eye conditions can look similar. These include dry eye, inflammation inside the eye, a corneal scratch, a corneal infection, and sudden pressure problems such as acute angle-closure glaucoma. The examination helps separate these conditions.

Treatment is based on the likely cause and the seriousness of the symptoms.

Simple comfort measures can help many forms of conjunctivitis. A cool, clean compress may reduce itching and swelling. A warm compress can loosen crusted discharge. Artificial tears may ease burning or grittiness.

Wash your hands before and after touching the area around your eyes. Use a clean cloth or cotton pad to remove discharge, wiping from the inner corner outward. Do not share the cloth.

Viral conjunctivitis usually improves as the immune system clears the infection. Antibiotics like amoxicillin or doxycycline do not treat viruses. Some viral infections, including herpes infections of the eye, need antiviral treatment and specialist assessment.

Mild bacterial conjunctivitis can sometimes clear without antibiotics. Antibiotic eye drops or ointment may shorten some bacterial infections and can be important when symptoms are more severe or complications are more likely. A healthcare professional can decide whether they are appropriate.

Do not use leftover antibiotic drops or another person’s medicine. Avoid eye drops containing steroids like prednisone or hydrocortisone unless they have been prescribed after an eye examination. Steroids can worsen certain infections and delay healing.

Conjunctivitis caused by gonorrhoea or chlamydia needs antibiotic treatment for the infection throughout the body, not only eye drops. Sexual partners may also need testing and treatment.

For allergic conjunctivitis, reducing contact with the trigger may help. Lubricating drops can rinse allergens from the eye. Antihistamine or combined antihistamine and mast-cell stabilising eye drops may control the allergic response. Persistent or severe allergy symptoms may need specialist care.

Stop wearing contact lenses while an eye is red or producing discharge. Disposable lenses and their case may need to be replaced, while reusable equipment must be cleaned according to professional and manufacturer instructions. Avoid eye makeup until the symptoms have cleared.

Most conjunctivitis does not cause lasting harm.

The main serious concern is inflammation or infection of the cornea, called keratitis. A deeper bacterial infection may form a corneal ulcer. Without timely treatment, this can lead to scarring and reduced vision.

Corneal involvement is more likely when there is significant pain, light sensitivity, reduced vision, a cloudy spot on the eye, or contact lens use. These symptoms need urgent assessment.

Some severe viral infections can leave small areas of inflammation in the cornea. This may cause glare or blurred vision for weeks or months, although it often improves gradually.

Newborns can develop serious eye damage from certain infections acquired around birth. Redness or discharge in a baby during the first month of life needs urgent medical assessment.

Not every case can be prevented. Allergic conjunctivitis may return when you are exposed to a trigger, and some infections spread before symptoms are obvious.

You can reduce the spread of infectious conjunctivitis by:

• Washing your hands regularly with soap and water
• Avoiding rubbing or touching your eyes
• Not sharing towels, pillows, cosmetics, or eye drops
• Cleaning frequently touched surfaces
• Using a separate clean cloth for each eye
• Following safe contact lens cleaning and replacement instructions

Never share contact lenses or lens equipment. Keep lenses away from tap water, swimming pools, and hot tubs unless you are wearing suitable protective eyewear and following lens guidance.

If pollen triggers symptoms, closing windows during high-pollen periods and washing your face after outdoor activity may reduce exposure. These steps may help but cannot guarantee prevention.

Many uncomplicated cases improve over several days. Viral conjunctivitis often lasts one to two weeks and sometimes longer. Symptoms may become more noticeable before they begin to settle.

Bacterial conjunctivitis may improve within days, with or without antibiotics, but this is not guaranteed. Seek follow-up if symptoms are worsening or are not responding to prescribed treatment.

Allergic conjunctivitis can continue or return while the trigger is present. Symptoms may follow a seasonal pattern. Ongoing problems can usually be managed by identifying triggers and using suitable allergy treatment.

During an infectious episode, frequent handwashing and avoiding shared personal items help protect people around you. You do not always need to stay away from work or school solely because of conjunctivitis. Whether you can attend depends on how well you feel, your ability to follow hygiene measures, and local workplace, school, or childcare policies.

Repeated episodes are worth discussing during routine care. Recurrent redness may be related to allergy, dry eye, eyelid inflammation, contact lens problems, or another eye condition rather than repeated infection.

Get emergency help now after a chemical splash. Begin rinsing the eye immediately with plenty of clean, lukewarm water and continue while arranging emergency advice. Do not delay rinsing to identify the chemical.

Emergency assessment is also appropriate for sudden major vision loss, a serious eye injury, or severe eye pain with headache, nausea, or vomiting.

Arrange urgent, same-day assessment if you have:

• Moderate or severe eye pain
• Strong sensitivity to light
• Blurred or reduced vision that does not clear with blinking
• A red, painful eye while wearing contact lenses
• A cloudy or white spot on the cornea
• A foreign object or recent eye injury
• A large amount of pus-like discharge
• Blisters around the eye or a history of eye herpes
• Rapidly increasing redness or eyelid swelling

A newborn younger than one month with red eyes or discharge needs urgent medical assessment.

Arrange routine medical follow-up if symptoms keep returning, are getting worse, remain unexplained, or are not improving as expected. You should also seek follow-up if prescribed treatment is not helping.

How can I tell whether pink eye is viral or bacterial?

Watery discharge and cold symptoms suggest a virus, while thick discharge may suggest bacteria. These clues are not reliable enough to confirm the cause. An eye examination may be needed, especially when symptoms are severe or unusual.

Is conjunctivitis contagious?

Viral and bacterial conjunctivitis can spread to other people. Allergic and irritant conjunctivitis are not contagious. Handwashing and not sharing towels, cosmetics, or eye products reduce the chance of spread.

Do I need antibiotic eye drops?

Not always. Antibiotics do not help viral or allergic conjunctivitis, and some mild bacterial cases clear without them. They may be recommended for certain bacterial infections or when the risk of complications is higher.

How long does pink eye last?

Many cases improve within several days to two weeks. Viral conjunctivitis can sometimes last two to three weeks. Allergic symptoms may continue or return while you remain exposed to the trigger.

Can I go to work or send my child to school?

Many people can return when they feel well enough and can manage hand hygiene and discharge. Fever or other illness may require staying home. Schools, childcare settings, and workplaces may have their own policies.

When can I wear contact lenses again?

Do not wear lenses while your eyes are red, painful, or producing discharge. Wait until symptoms have cleared and any recommended treatment is complete. If the red eye occurred while wearing lenses, seek prompt assessment before using them again.