Conjunctivitis (pink eye): symptoms and treatment (UK guide)

Conjunctivitis — 'pink eye' — is the most common eye infection in the UK. Most cases settle without treatment within 1–2 weeks, but knowing the type matters: viral and bacterial conjunctivitis are contagious, while allergic conjunctivitis is not. This guide covers all three.

Viral conjunctivitis

The commonest cause in adults. Usually triggered by adenovirus, often alongside a cold or sore throat.

- Watery discharge, redness, gritty feeling

- Starts in one eye and often spreads to the other within a few days

- Highly contagious for 10–14 days — avoid sharing towels and stay off work/school until discharge stops

- Antibiotics do **not** help. Cool compresses and preservative-free lubricants ease symptoms.

See a specialist if vision blurs, light sensitivity develops, or symptoms last more than 2 weeks — some adenoviral strains cause corneal inflammation (subepithelial infiltrates) that responds to steroid drops.

Bacterial conjunctivitis

Less common in adults; more common in children.

- Thick yellow or green discharge, lashes stuck together in the morning

- Usually one eye first

- Settles in 5–7 days without treatment in most adults

- Chloramphenicol drops (over the counter in the UK) shorten symptoms and are reasonable if discharge is heavy

- Contact lens wearers should stop lens wear immediately and be seen the same day, as bacterial keratitis can present similarly and threatens sight

Allergic conjunctivitis

Not an infection. Caused by pollen, dust mite, animal dander or contact allergens (eye drops, make-up, hair dye).

- Itchy, watery, both eyes affected simultaneously

- Often with lid swelling, sneezing or a runny nose

- Peak season in the UK: May–July for grass pollen

- Treatment: mast-cell stabiliser drops (sodium cromoglicate) daily through the season, or antihistamine drops (olopatadine) for episodes

- Oral antihistamines help systemic symptoms

Neonatal conjunctivitis — always urgent

A discharging eye in a baby under 28 days old is a medical emergency. It can be caused by gonorrhoea, chlamydia or herpes acquired at birth and needs same-day hospital assessment.

When to see an eye specialist urgently

Same-day review is needed if you have:

- Pain (not just grittiness)

- Blurred or reduced vision

- Marked light sensitivity

- A contact lens in place with a red eye

- Symptoms after eye trauma or surgery

- A cloudy patch on the cornea

These features suggest keratitis, uveitis or angle-closure glaucoma rather than conjunctivitis.

How long am I contagious?

Viral conjunctivitis: contagious as long as the eye is discharging or streaming, typically 10–14 days.

Bacterial conjunctivitis: contagious for the first 24 hours of antibiotic drops, or 48 hours without.

Allergic conjunctivitis: not contagious at all.

Next steps

If you have a red eye that is painful, light-sensitive, blurring your vision, or lasting more than two weeks, please book a consultation or call **020 3137 3237**. For a broader overview, see our eye conditions guide.