Bacterial Conjunctivitis
Acute purulent conjunctival infection — most often self-limited; topical antibiotics shorten course.
Also known as: bacterial conjunctivitis, pink eye bacterial, mucopurulent conjunctivitis, hyperacute conjunctivitis
Overview
Acute infection of the conjunctiva characterized by mucopurulent discharge, conjunctival hyperemia, and crusted/'stuck shut' eyelids. Distinguished from viral and allergic conjunctivitis by the character of discharge and clinical context.
Epidemiology
Most common in children; ~50-75% of pediatric conjunctivitis is bacterial. Adults more often viral. Hyperacute (gonococcal) and chlamydial conjunctivitis affect sexually active adults and neonates of infected mothers.
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Risk factors
- Direct contact with infected secretions
- Contact lens wear (Pseudomonas, especially with poor hygiene or extended wear)
- Recent upper respiratory infection (otitis-conjunctivitis syndrome — H. influenzae)
- Crowded settings (schools, daycare)
- Neonates born to mothers with untreated chlamydia or gonorrhea
- Sexual transmission (gonococcal, chlamydial)
- Immunocompromise
Pathophysiology
Bacterial inoculation of the conjunctival surface triggers a neutrophilic response, producing the characteristic purulent discharge. Common organisms in adults: Staphylococcus aureus, Streptococcus pneumoniae; in children: H. influenzae (often non-typeable), S. pneumoniae, M. catarrhalis. Pseudomonas aeruginosa in contact lens wearers. Neisseria gonorrhoeae produces hyperacute infection that can perforate the cornea within 24-48 h. Chlamydia trachomatis causes neonatal inclusion conjunctivitis and chronic adult inclusion conjunctivitis.
Clinical presentation
Symptoms
- Eye redness, often beginning unilateral and spreading to fellow eye in 1-2 days
- Mucopurulent (yellow/green) discharge throughout the day
- Eyelids matted/stuck shut on awakening
- Foreign body or 'gritty' sensation
- Minimal or no itching (helps differentiate from allergic)
- Mild discomfort; significant pain, photophobia, or vision loss suggests another diagnosis
Signs / physical exam
- Diffuse bulbar and palpebral conjunctival injection
- Purulent discharge — copious in hyperacute (gonococcal)
- Lid edema and crusting
- Cornea clear; visual acuity preserved
- No preauricular lymphadenopathy (unlike viral or gonococcal)
- Severe chemosis and lid edema in hyperacute gonococcal infection
Classic findings
Bilateral mucopurulent discharge with eyelids matted shut on awakening and normal vision in a school-age child.
Differential diagnosis
- Viral conjunctivitis — Watery discharge, preauricular lymphadenopathy, recent URI; often bilateral after starting unilateral; supportive care
- Allergic conjunctivitis — Itching is hallmark, bilateral, watery discharge, chemosis, atopic history; antihistamine/mast cell stabilizer drops
- Hyperacute (gonococcal) conjunctivitis — Copious purulent discharge accumulating within minutes of wiping, severe lid edema, preauricular adenopathy; vision-threatening — Gram stain and culture, IM ceftriaxone PLUS topical therapy
- Adult chlamydial inclusion conjunctivitis — Chronic >2 weeks, mucopurulent, follicular reaction, sexually active; NAAT; treat with azithromycin or doxycycline + partner therapy
- Neonatal conjunctivitis (ophthalmia neonatorum) — Day of onset clues: chemical (day 0-1), gonococcal (2-5), chlamydial (5-14), HSV (1-2 weeks); gonococcal needs IV ceftriaxone — do not miss
- Keratitis (bacterial, HSV, contact lens) — Pain, photophobia, decreased vision, corneal infiltrate on slit lamp; same-day ophthalmology
- Iritis/uveitis — Pain, photophobia, ciliary flush, miotic pupil, cells/flare on slit lamp; ophthalmology referral
- Acute angle-closure glaucoma — Severe pain, vomiting, halos around lights, mid-dilated fixed pupil, hazy cornea, IOP >40; emergency
- Subconjunctival hemorrhage — Painless flat red blood under conjunctiva; no discharge or visual change; self-resolves
Diagnostic workup
Labs
- Most cases: clinical diagnosis; no testing needed
- Gram stain and culture if: hyperacute presentation, contact lens wearer, severe disease, neonate, immunocompromised, treatment failure
- NAAT for Chlamydia trachomatis and Neisseria gonorrhoeae in adults with suspected STI conjunctivitis or in neonatal conjunctivitis
Imaging
- Slit-lamp examination if any pain, photophobia, decreased vision, contact lens wear, or treatment failure — exclude keratitis or iritis
- Fluorescein staining if corneal involvement suspected
Diagnostic algorithm
| Feature | Bacterial | Viral | Allergic |
|---|---|---|---|
| Discharge | Mucopurulent (yellow-green) | Watery | Stringy/mucoid, watery |
| Itching | Minimal | Mild | Hallmark (severe) |
| Laterality | Often bilateral | Often starts unilateral | Bilateral |
| Preauricular node | Absent (present in gonococcal) | Present | Absent |
| URI features | Sometimes | Often | No |
| Atopic history | — | — | Yes |
| First-line treatment | Topical antibiotic | Supportive (cool compress) | Antihistamine/MCS drops |
Treatment
First-line
- Most uncomplicated bacterial conjunctivitis is self-limited; topical antibiotics shorten course and reduce transmission
- Topical ocular antibiotic — erythromycin ophthalmic ointment 0.5%, polymyxin B/trimethoprim drops, or moxifloxacin/ofloxacin drops × 5-7 days
- Avoid topical aminoglycosides (gentamicin, tobramycin) as first line — corneal toxicity and limited gram-positive coverage
- Frequent warm compresses to remove crusts; hand hygiene and dedicated towels to reduce spread
- Contact lens wearers: discontinue lenses, use a topical fluoroquinolone (ciprofloxacin or moxifloxacin) for pseudomonal coverage, refer if any corneal involvement
- Discard contaminated cosmetics and replace lenses/case after resolution
Second-line / adjunct
- Hyperacute (gonococcal) conjunctivitis: ceftriaxone 1 g IM × 1 (or 25-50 mg/kg up to 125 mg IM/IV for neonates) PLUS saline irrigation PLUS topical erythromycin or ciprofloxacin; treat presumptively for chlamydia co-infection (azithromycin 1 g PO or doxycycline 100 mg BID × 7 days); ophthalmology referral
- Adult chlamydial conjunctivitis: azithromycin 1 g PO × 1 OR doxycycline 100 mg PO BID × 7 days plus partner treatment
- Neonatal chlamydial conjunctivitis: oral erythromycin × 14 days (topical does not eradicate nasopharyngeal carriage); monitor for pyloric stenosis
- Neonatal gonococcal conjunctivitis: IV/IM ceftriaxone (single dose 25-50 mg/kg, max 125 mg) plus saline irrigation; admit
- Same-day ophthalmology referral for any contact lens wearer with corneal involvement, suspected gonococcal infection, no improvement at 48 h, or vision-threatening signs
Complications
- Corneal ulceration and perforation (hyperacute gonococcal or Pseudomonas in contact lens wearer)
- Keratitis with permanent vision loss
- Conjunctival scarring (chronic chlamydial — trachoma; leading global cause of preventable blindness)
- Spread to fellow eye and close contacts
- Pneumonia in neonates with chlamydial conjunctivitis (~10-20%)
PANCE pearls
- Discharge type is a clinical clue (imperfect): purulent → bacterial; watery → viral; stringy/mucoid + itching → allergic.
- Hyperacute purulent conjunctivitis = gonococcal until proven otherwise — sight-threatening; treat systemically with ceftriaxone and refer to ophthalmology.
- All contact lens wearers with bacterial conjunctivitis require fluoroquinolone coverage for Pseudomonas and prompt ophthalmology evaluation.
- Neonatal conjunctivitis timing: chemical (day 0-1), gonococcal (2-5), chlamydial (5-14), HSV (1-2 weeks).
- Otitis-conjunctivitis syndrome in a child suggests H. influenzae — systemic amox-clav covers both.
References
- AAO 2018 — American Academy of Ophthalmology. Conjunctivitis Preferred Practice Pattern. Ophthalmology 2019;126(1):P94-P169
- CDC STI 2021 — Centers for Disease Control and Prevention. Sexually Transmitted Infections Treatment Guidelines, 2021. MMWR Recomm Rep 2021;70(4):1-187
- AAP Red Book 2024 — American Academy of Pediatrics. Chlamydia trachomatis / Neisseria gonorrhoeae infections. In: Red Book 2024
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