AKT · Ophthalmology/Lids & surface

Bacterial conjunctivitis

Acute bacterial infection of the conjunctiva (Staph aureus, Strep pneumoniae, H. influenzae; Neisseria/Chlamydia in specific settings)

Overview

Acute infective conjunctivitis with purulent discharge, usually self-limiting (5–7 days). Most need no antibiotic; topical chloramphenicol if severe or rapid resolution required. Hyperacute purulent conjunctivitis in a sexually active adult/neonate raises gonococcal/chlamydial causes (ophthalmia neonatorum).

Recognise

Acute red eye with PURULENT (yellow-green) discharge; lids stuck together on waking
Often starts unilateral then spreads to the other eye; gritty discomfort, NOT true pain
Normal vision and pupils; no photophobia (if present, suspect keratitis/uveitis)

Red flags

Hyperacute copious purulent discharge with rapid corneal involvement → gonococcal — emergency (corneal perforation risk)
Neonate (ophthalmia neonatorum) → urgent: gonococcus (day 1–5) or chlamydia (day 5–14)
Contact-lens wearer with a red painful eye → exclude microbial keratitis (refer)

Differentials & how to tell them apart

Viral conjunctivitiswatery discharge, preauricular node, recent URTI, follicular reaction

Allergic conjunctivitisbilateral itch with stringy mucus and chemosis, atopic history

Anterior uveitis / keratitistrue pain, photophobia, reduced vision, circumcorneal injection — a red flag, not simple conjunctivitis

Acute angle-closure glaucomapainful red eye with haloes, fixed mid-dilated pupil, hazy cornea, nausea

Bacterial conjunctivitis — purulent discharge, injected conjunctiva
Adriano / CC BY-SA 4.0 — Wikimedia Commons

Investigations

Clinical. Swab (bacterial culture ± viral PCR/chlamydia) if severe, recurrent, neonatal, or treatment-resistant.

Management

Self-care + hygiene; topical chloramphenicol only if severe or rapid resolution needed

1Reassure (self-limiting, 5–7 days). Lid hygiene and avoid sharing towels. Delayed-antibiotic strategy: chloramphenicol if not settling in 3 days, or immediately if severe.Gate: Do NOT treat as simple conjunctivitis if there is true PAIN, PHOTOPHOBIA, reduced VISION, or it is a CONTACT-LENS wearer — these need referral (keratitis/uveitis); hyperacute purulent discharge = gonococcal emergency; neonatal conjunctivitis is urgent
2Persistent >7–10 days → swab and ophthalmology referral. Gonococcal → IM ceftriaxone + ophthalmology. Chlamydial → oral azithromycin/doxycycline + partner treatment.

Self-care + hygiene — bathe lids, separate towels; most resolve without antibiotics

Chloramphenicol 0.5% drops / 1% ointment — first-line topical antibiotic if treatment chosen (delayed strategy: start if not resolved in 3 days)

Fusidic acid 1% drops — alternative (twice daily); useful in pregnancy

Aminoglycoside/quinolone drops — contact-lens-associated, to cover Gram-negatives (Pseudomonas)

Key points

Discharge type sorts it: purulent=bacterial, watery=viral, stringy+itch=allergic. Pain/photophobia/visual loss means it is NOT conjunctivitis.

Monitor & prognosis

Resolution by 7 days; review if not.

Excellent; self-limiting in immunocompetent adults.

Source: NICE CKS Conjunctivitis – infective