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Conjunctivitis (Pink Eye): Types, Symptoms, Causes and Treatment
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Conjunctivitis (noun, also called pink eye): inflammation of the conjunctiva, the thin, clear membrane that covers the white of the eye and lines the inside of the eyelids. It is caused by a virus, bacteria or an allergy, and makes the eye red, watery, itchy or sticky. Most cases clear up on their own within one to two weeks, but a painful eye or blurred vision is never normal conjunctivitis and needs a doctor the same day. At Laser Istanbul Clinic, eye infections are assessed by Doç. Dr. Muhammet Derda Özer (Doç. = Associate Professor), our cornea specialist.
Conjunctivitis: key facts
- What it is
- Inflammation of the conjunctiva, in one or both eyes
- Main types
- Viral (most common), bacterial, allergic; less often chemical, contact-lens-related or other causes
- Typical symptoms
- Red or pink eye, gritty or burning feeling, watering, itching, sticky discharge
- How long it lasts
- Usually 1–2 weeks (AAO); the NHS says "a couple of weeks"
- Contagious?
- Viral and bacterial: yes. Allergic: no
- Antibiotics needed?
- Only for bacterial cases; they do not work on viral or allergic conjunctivitis
- Urgent signs
- Eye pain, light sensitivity, blurred vision, very red eye, or a baby under 30 days old with red, sticky eyes
- Specialist
- Ophthalmologist; at Laser Istanbul Clinic, Doç. Dr. Muhammet Derda Özer
What are the types of conjunctivitis?
Conjunctivitis has three main causes, and telling them apart matters because the treatment is different. The American Academy of Ophthalmology (AAO) and the US Centers for Disease Control and Prevention (CDC) describe the same three groups.
| Type | Typical picture | Contagious? | Treatment in short |
|---|---|---|---|
| Viral conjunctivitis | Burning, red eyes with a watery discharge, often alongside a cold or sore throat | Yes, highly | No specific treatment; cool compresses and artificial tears while it clears |
| Bacterial conjunctivitis | Sore, red eyes with thick, sticky discharge; lids may be stuck together on waking | Yes | Antibiotic eye drops when a doctor decides they are needed |
| Allergic conjunctivitis | Itchy, red, watery eyes with puffy lids, usually both eyes, often with hay fever | No | Avoid the trigger; allergy eye drops or antihistamines |
Less common forms include chemical conjunctivitis (from a splash or irritant), conjunctivitis linked to contact lenses, and forms caused by herpes viruses or sexually transmitted bacteria. Conjunctivitis that starts in the first month of life is a separate, urgent problem (see below).
What are the symptoms of conjunctivitis?
Conjunctivitis symptoms, according to the NHS, are eyes that are red, burn or feel gritty, itch, water, or produce pus that sticks to the lashes. One eye is often affected first and the other may follow. The details help point to the cause:
- Viral: watery discharge, a burning or gritty feeling, often with cold symptoms.
- Bacterial: more sticky, yellow-green discharge; eyelids that are glued shut after sleep. Some soreness is common.
- Allergic: itching is the main sign; both eyes are red and watery, often with a runny nose or sneezing.
Conjunctivitis should not cause real pain, marked light sensitivity or blurred vision that does not clear when you blink. If it does, the cornea (the clear front window of the eye) may be involved, which is a more serious problem than conjunctivitis. See "When to see a doctor" below.
What causes conjunctivitis?
Viruses. Viruses cause most infectious conjunctivitis in adults. EyeWiki, the AAO's clinical encyclopaedia, puts viral causes at about 80% of infectious cases, and adenoviruses (the family that also causes colds) at 65–90% of the viral ones. The CDC also lists other viruses, including herpes viruses.
Bacteria. Bacterial conjunctivitis is the second most common infectious cause. The CDC lists Haemophilus influenzae, Streptococcus pneumoniae and Staphylococcus aureus among the bacteria involved; some sexually transmitted bacteria (chlamydia and gonorrhoea) can also infect the eye.
Allergy. Pollen, dust mites, pet dander, mould, cosmetics and contact lenses can trigger allergic conjunctivitis. EyeWiki estimates allergic eye disease affects 15–40% of people. Seasonal and year-round forms are the most common; rarer chronic forms (vernal, atopic and giant papillary conjunctivitis) need specialist care.
Other causes. Chemical splashes, smoke, chlorine, foreign bodies and contact lens problems can irritate the conjunctiva. In parts of the world with limited water and sanitation, repeated infection with the bacterium Chlamydia trachomatis causes trachoma, a leading infectious cause of blindness. The World Health Organization (WHO) reported in March 2026 that 92 million people live in trachoma-endemic areas.
Is conjunctivitis contagious, and for how long?
Viral and bacterial conjunctivitis are contagious; allergic conjunctivitis is not. The infection spreads through direct contact: touching an infected eye then touching your own, or sharing towels, pillows, make-up and other items. The CDC says viral and bacterial pink eye spread easily from person to person.
- Viral conjunctivitis: EyeWiki gives an incubation period of 5–12 days and a contagious period of about 10–14 days.
- Epidemic keratoconjunctivitis (EKC): a severe adenovirus form. People can be contagious for two weeks or longer after symptoms begin, and in roughly 70% of cases it spreads to the second eye.
- Bacterial conjunctivitis: contagious while there is discharge.
- Allergic conjunctivitis: not contagious at all, even when both eyes are red and watery.
How long does conjunctivitis last?
Conjunctivitis usually goes away on its own within one to two weeks (AAO), and the NHS says it "usually gets better in a couple of weeks without treatment." See a GP if it has not improved after 7 days. Allergic conjunctivitis lasts as long as you are exposed to the trigger, so it can return every season.
EKC can leave small spots of inflammation on the cornea around day 10 (called subepithelial infiltrates). EyeWiki notes these can cause glare, light sensitivity and blurred vision that last for months or even years in some people, which is why symptoms that persist after the redness has gone deserve a proper check.
How is conjunctivitis diagnosed?
Doctors diagnose conjunctivitis mainly from your history and an examination, because the signs differ by cause.
History
The doctor asks about discharge, itching, contact lens wear, recent colds, allergies and contact with anyone with red eyes.
Vision and eye check
Your vision is checked, and the lids, conjunctiva and cornea are examined, usually with a slit lamp (a microscope with a bright, thin beam of light). This is how a specialist spots corneal involvement that a quick look would miss.
Signs that point to the cause
Watery discharge and a swollen gland in front of the ear point to a virus; thick pus points to bacteria; small bumps under the upper lid and a velvety conjunctiva point to allergy.
Swab or culture
EyeWiki notes that a culture is advised for purulent discharge, and referral is advised for contact lens wearers and for symptoms that last beyond 7–10 days.
How is conjunctivitis treated?
| Cause | Main treatment | Antibiotics? |
|---|---|---|
| Viral | Cool compresses and artificial tears; wait for it to clear. Antiviral treatment only in specific cases, such as herpes viruses | No: they do not work on viruses |
| Bacterial | Clean the lids, then antibiotic drops or ointment if the doctor judges them necessary | Yes, when bacterial infection is likely or confirmed |
| Allergic | Avoid the trigger; cold compresses; allergy eye drops or antihistamines; stronger treatment from a specialist when severe | No |
| Chemical | Rinse the eye thoroughly with clean water at once, then see a doctor urgently | No |
Home care. The NHS suggests washing the eyelids with clean water and holding a cold flannel over the eyes for a few minutes to cool them. Do not wear contact lenses until you have recovered.
Antibiotic drops. Antibiotics are only for bacterial infections, and the NHS says they are ineffective against viral and allergic conjunctivitis. Children under 2 need a prescription for treatment. Contact lens wearers with pus-like discharge should stop wearing lenses and be seen promptly by an eye doctor; the CDC advises antibiotic drops and prompt assessment by an ophthalmologist.
Steroid drops. Steroid drops are prescribed only by an eye specialist, for example for severe allergic disease. EyeWiki notes that steroids can prolong epidemic keratoconjunctivitis, so never use leftover steroid drops without being told to.
Treatment with us: infections that will not settle, repeated attacks and corneal complications such as scarring are assessed by Doç. Dr. Muhammet Derda Özer, who leads cornea, uveitis and ocular infection care. If you are in Istanbul and your eye is painful or your vision has dropped, seek same-day care locally first; a second opinion can follow.
Conjunctivitis in newborns
Conjunctivitis in the first 30 days of life is an emergency. The NHS tells parents to get an urgent GP appointment, or call NHS 111, for any baby under 30 days with red, sticky eyes. EyeWiki explains why: some causes can damage the cornea and, if not treated quickly, lead to scarring and blindness. The timing hints at the cause:
| Cause | Typical start after birth |
|---|---|
| Chemical irritation (from preventive drops) | Within 24 hours |
| Gonorrhoea | 3–5 days |
| Chlamydia | 5–14 days |
| Herpes simplex virus | 1–2 weeks |
How can you stop conjunctivitis spreading?
The CDC and NHS give the same practical advice for anyone with infectious conjunctivitis:
- Wash your hands often with soap and water for at least 20 seconds, especially after touching your eyes.
- Avoid rubbing or touching your eyes; with clean hands, wipe away discharge several times a day.
- Do not share towels, pillows, washcloths, make-up, eye drops or glasses.
- Wash pillowcases, sheets and face cloths in hot water and detergent.
- Stop wearing contact lenses until symptoms have gone and your eye doctor says it is safe. Throw away disposable lenses and the lens case you used during the infection.
- Avoid swimming pools while the eye is infected.
Work and school. The NHS says you do not need to stay away from work or school unless you or your child feel very unwell. The CDC advises that people who cannot avoid close contact with others should stay home until any needed treatment has started. Follow any local rule for your school or workplace.
No single vaccine prevents all conjunctivitis, according to the CDC, although vaccination against illnesses such as measles and chickenpox prevents some eye infections that come with them.
When to see a doctor about conjunctivitis
Seek same-day care from an eye doctor, your GP, NHS 111 or an emergency eye service if you have:
- eye pain, not just irritation or grittiness
- sensitivity to light
- blurred vision, or changes in vision such as wavy lines or flashing lights
- a very red eye (one or both)
- contact lenses and a red eye with pus-like discharge (take the lenses out and do not put them back in)
- a recent eye operation, eye injury or chemical splash
- a baby under 30 days old with red, sticky eyes
Book an appointment if:
- symptoms have not improved after 7 days (NHS advice)
- the redness keeps coming back
- itching and redness come every season and simple treatment has not helped
- blurred vision, glare or light sensitivity continue after the redness has gone
If you have a diagnosis from home and want a specialist's second opinion on an infection that keeps returning, or on scarring on the cornea, you can send your reports for review.
Frequently asked questions
Conjunctivitis, or pink eye, is inflammation of the conjunctiva, the clear membrane over the white of the eye and inside the eyelids. It is caused by a virus, bacteria or an allergy, and it usually clears up on its own within one to two weeks.
The main symptoms are red or pink eyes, a gritty or burning feeling, itching, watering, and a sticky discharge that can glue the lashes together. Allergic conjunctivitis is mostly itchy and watery. Pain, light sensitivity or blurred vision are not typical and need urgent assessment.
Viruses cause most infectious conjunctivitis in adults, followed by bacteria. Allergies to pollen, dust mites, pets or cosmetics cause the non-infectious form. Chemical irritants, contact lens problems and some sexually transmitted infections are less common causes.
Viral and bacterial conjunctivitis are contagious, and spread by touch and shared items such as towels and pillows. Viral cases can be infectious for about 10–14 days, and the severe adenovirus form EKC for two weeks or longer. Allergic conjunctivitis is not contagious.
Most cases clear within one to two weeks. See a GP if there is no improvement after 7 days, or earlier if you have pain, light sensitivity or blurred vision. Allergic conjunctivitis lasts as long as the trigger is present.
Only if it is bacterial. Antibiotic drops do nothing for viral or allergic conjunctivitis, so a doctor or pharmacist decides whether they are needed. Children under 2 need a prescription, and contact lens wearers should be seen promptly by an eye doctor.
According to the NHS, you do not need to stay off work or school unless you feel very unwell, but good hygiene is essential. Some schools and workplaces have their own rules, and the CDC advises staying home if you cannot avoid close contact with others.
No. The NHS and CDC both advise stopping lenses until you have recovered, throwing away lenses and cases used during the infection, and following your eye doctor's instructions before restarting. If you wear lenses and your eye is red and painful, get seen the same day.
Conjunctivitis affects the membrane over the white of the eye; a stye is a painful lump in the eyelid, and blepharitis is inflammation of the eyelid edges. They can occur together, and either can make an eye look red. See our guides on stye (hordeolum) and blepharitis.
Sources for the facts on this page
- NHS. Conjunctivitis (overview, symptoms, treatment). https://www.nhs.uk/conditions/conjunctivitis/ · https://www.nhs.uk/conditions/conjunctivitis/symptoms/ · https://www.nhs.uk/conditions/conjunctivitis/treatment/
- American Academy of Ophthalmology. Pink Eye (Conjunctivitis). https://www.aao.org/eye-health/diseases/pink-eye-conjunctivitis
- US Centers for Disease Control and Prevention. About Pink Eye (Conjunctivitis). https://www.cdc.gov/conjunctivitis/about/index.html
- CDC. Clinical Overview of Pink Eye. https://www.cdc.gov/conjunctivitis/hcp/clinical-overview/index.html
- CDC. Preventing and Managing Pink Eye. https://www.cdc.gov/conjunctivitis/about/prevention.html
- EyeWiki (AAO). Conjunctivitis. https://eyewiki.org/Conjunctivitis
- EyeWiki (AAO). Epidemic Keratoconjunctivitis. https://eyewiki.org/Epidemic_Keratoconjunctivitis
- EyeWiki (AAO). Neonatal Conjunctivitis. https://eyewiki.org/Neonatal_Conjunctivitis
- World Health Organization. Trachoma fact sheet (data as of March 2026). https://www.who.int/news-room/fact-sheets/detail/trachoma
Red eye that will not settle, or keeps coming back?
Send us your eye report or describe your symptoms. Doç. Dr. Muhammet Derda Özer, our cornea specialist, will review them and tell you what the next step should be, with no obligation. If your eye is painful or your vision is dropping, see a doctor today, wherever you are.
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