Conjunctivitis (bacterial)


Self-limiting bacterial infection of the conjunctiva, typically by:

  • Staphylococcus species (Gram +ve)
  • Streptococcus pneumoniae (Gram +ve)
  • Haemophilus influenzae (especially in children) (Gram –ve)
  • Moraxella catarrhalis (Gram-ve)

Predisposing factors

Children and the elderly have an increased risk of infective conjunctivitis
(NB Bacterial conjunctivitis in the first month of life is a serious condition that must be referred urgently to the ophthalmologist. See Clinical Management Guideline on Ophthalmia Neonatorum)

  • contamination of the conjunctival surface
  • superficial trauma
  • contact lens wear (particularly poor lens hygiene) (NB infection may be Gram –ve)
  • secondary to viral conjunctivitis (NB refer also to Clinical Management Guideline on Conjunctivitis (viral, non-herpetic)
  • diabetes (or other disease compromising the immune system)
  • steroids (systemic or topical, compromising ocular resistance to infection)
  • blepharitis (or other chronic ocular inflammation)

Symptoms of bacterial conjunctivitis

Acute onset of:

  • redness
  • discomfort, usually described as burning or grittiness
  • discharge (may cause temporary blurring of vision)
  • crusting of lids (often stuck together after sleep and may have to be bathed open)

Usually bilateral – one eye may be affected before the other (by one or two days)

Signs of bacterial conjunctivitis

  • lid crusting
  • purulent or mucopurulent discharge
  • conjunctival hyperaemia – maximal in fornices
  • tarsal conjunctiva may show mild papillary reaction
  • cornea: usually no involvement (occasionally superficial punctate keratitis – mainly in lower third of cornea). If cornea significantly involved, consider possibility of gonococcal infection
  • pre-auricular lymphadenopathy: usually absent

Differential diagnosis

Other forms of conjunctivitis

Other causes of acute red eye

Management by optometrist

Practitioners should work within their scope of practice, and where necessary seek further advice or refer the patient elsewhere

GRADE* level of evidence and strength of recommendation always relates to the statement(s) immediately above

Non pharmacological

Bathe/clean the eyelids with proprietary sterile wipes, lint or cotton wool dipped in sterile saline or boiled (cooled) water to remove crusting
(GRADE*: Level of evidence = low, Strength of recommendation = strong)

Advise patient that condition is contagious (do not share towels, etc.)

Public health guidance in all UK Nations states that school or nursery exclusion is not required for children with this condition


Often resolves in 5-7 days without treatment

Treatment with topical antibiotics may modestly improve short-term clinical remission and render patient less infectious to others; however the potential benefit of antibiotics needs to be balanced against the risk of antibiotic resistance
(GRADE*: Level of evidence = high, Strength of recommendation = strong)

Topical antibiotics (with no evidence of superiority of particular antibiotics) may include: chloramphenicol 0.5% eye drops, chloramphenicol 1% ointment, azithromycin 1.5% eye drops, fusidic acid 1% viscous eye drops (NB high cost and narrower spectrum of activity than chloramphenicol)

Evidence for the benefit of antibiotics is based on the conclusions of a Cochrane Review (Sheikh and Hurwitz 2012) which included trials conducted in primary and secondary care. However, an individual patient meta-analysis of studies exclusively based in primary care (Jefferis et al 2011) found only a marginal benefit of antibiotics over placebo. Predictors of bacterial culture positivity at presentation include purulent discharge and age less than 5 years. The NICE Clinical Knowledge Summary (CKS) suggests that a delayed treatment strategy may be appropriate i.e., advise the person to initiate topical antibiotics only if symptoms fail to resolve within 3 days of onset.

Contact lens wearers with a diagnosis of bacterial conjunctivitis should be treated with a topical antibiotic effective against Gram –ve organisms, such as an aminoglycoside (e.g. gentamycin) or a quinolone (e.g. levofloxacin or moxifloxacin) Contact lenses should not be worn until the condition has resolved.
(GRADE*: Level of evidence = low, Strength of recommendation = strong).

Advise patient to return/seek further help if symptoms persist beyond 7 days

Management category

B3: management to resolution. Refer if condition fails to resolve, or if there is corneal involvement.

A3: If condition fails to resolve, or if there is corneal involvement, urgent referral (within one week) to ophthalmologist

Possible management in secondary care or local primary/community pathways where available

Additional guidance may be available

If resistant to treatment, or recurrent:

  • conjunctival swabs taken for microscopy and culture and/or PCR analysis
  • treatment with other antibiotics, based on culture results

Evidence base

* GRADE: Grading of Recommendations, Assessment, Development and Evaluation (

Sources of evidence

Jefferis J, Perera R, Everitt H, van Weert H, Rietveld R, Glasziou P, Rose P. Acute infective conjunctivitis in primary care: who needs antibiotics? An individual patient data meta-analysis. Br J Gen Pract. 2011;61(590):e542-8

NICE. Clinical Knowledge Summary. Conjunctivitis – infective. 2022

UK Health Security Agency. Guidance. Managing specific infectious diseases: A to Z. 2022

Sheikh A, Hurwitz B, van Schayck CP, McLean S, Nurmatov U. Antibiotics versus placebo for acute bacterial conjunctivitis. Cochrane Database of Syst Rev. 2012;9:CD001211


What is bacterial Conjunctivitis?

Acute bacterial conjunctivitis is an infection of the eye in which one or both eyes become red, watery and sticky, often with discomfort but not pain. The condition is not normally serious and in most cases clears up in a few days. However, it is contagious and care needs to be taken to avoid spread of the infection amongst family members (e.g. not sharing towels etc.). 

How is bacterial Conjunctivitis managed?

People with acute conjunctivitis may be given antibiotics, usually in the form of eye drops or ointment, to speed recovery. However, the benefits of antibiotics for the treatment of acute bacterial conjunctivitis have been questioned. Evidence from clinical trials in GP practices suggests that antibiotic drops may not be very helpful, since these patients tend to have a less severe form of conjunctivitis than patients who are referred to a hospital eye clinic.

Conjunctivitis (bacterial)
Version 14
Date of search 17.10.22
Date of revision 20.12.22
Date of publication 20.02.23
Date for review 16.10.24
© College of Optometrists 

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