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OP3.2 | Acute Conjunctivitis: Bacterial and Viral Patterns — SDL Guide (Part 3)
Management Principles and Prevention
The management strategy for acute conjunctivitis is driven entirely by the aetiology. The error of prescribing topical antibiotics indiscriminately — regardless of aetiology — is one of the most common in primary care ophthalmology. The principles below are derived from Khurana and Parsons' and are consistent with current evidence. This means that determining the aetiology — bacterial versus viral versus chlamydial versus gonococcal — is not an academic exercise but the prerequisite for correct treatment. A clinician who cannot distinguish viral from bacterial conjunctivitis by clinical features will inevitably prescribe antibiotics to patients who do not need them (promoting resistance and providing no benefit) and will miss the small proportion of cases that require systemic treatment or urgent referral. The management framework below is organised by aetiology, so that the correct treatment decision follows logically from the clinical diagnostic step covered in the preceding sections. Learn the framework aetiology-by-aetiology rather than as a flat list of drug names, and the decisions will be durable rather than memorised.
Bacterial conjunctivitis (non-gonococcal):
- Topical antibiotics shorten the course by 1–2 days and reduce infectivity.
- First-line options: topical chloramphenicol 0.5% drops (4× daily for 7 days) or topical ciprofloxacin 0.3% drops (for contact-lens wearers — avoid chloramphenicol due to the risk of aplastic anaemia in contact-lens wearers, a theoretical but documented concern).
- Hygiene counselling: regular hand washing, individual towels, avoid rubbing eyes.
- Swabs for culture are NOT routinely needed unless the case is atypical, severe, fails treatment, or is neonatal.
Gonococcal conjunctivitis (hyperacute):
- Systemic ceftriaxone (1 g IM single dose in adults; weight-based in neonates) — topical alone is inadequate.
- Hourly saline irrigation of the conjunctival sac to reduce gonococcal load.
- Same-day ophthalmology referral.
- Investigate for genital infection and treat sexual partners.
Chlamydial inclusion conjunctivitis:
- Systemic azithromycin (1 g single oral dose) or systemic doxycycline (100 mg twice daily for 7 days); topical alone is insufficient as it does not treat concomitant urogenital infection.
- Screen and treat sexual contacts.
Neonatal (ophthalmia neonatorum):
- Gonococcal: IV/IM ceftriaxone + saline irrigation.
- Chlamydial: oral erythromycin (12.5 mg/kg 4× daily for 14 days) — topical alone inadequate due to nasopharyngeal involvement.
- Prophylaxis at birth: 1% tetracycline ointment or 0.5% erythromycin ointment (WHO recommendation).
Viral conjunctivitis:
- Treatment is supportive: cold compresses, lubricant drops, advice on hygiene.
- Antibiotics are NOT indicated.
- For EKC: strict infection control (hand hygiene, no sharing of eye drops, school/clinic exclusion for 2 weeks).
- For HSV primary conjunctivitis: topical aciclovir 3% ointment 5× daily.
- For AHC: symptomatic only; resolution in 5–10 days.
Prevention across all infectious types:
- Hand hygiene is the single most effective preventive measure.
- Do not share eye drops, towels, or contact lenses.
- Adenoviral EKC: Disinfect clinical equipment (slit-lamp chin-rest, tonometer tip) with dilute hypochlorite; the virus is resistant to standard alcohol-based disinfectants.
SELF-CHECK
A 24-year-old woman presents with bilateral watery red eyes, follicular reaction on eversion, tender preauricular nodes bilaterally, and mild fever. She works as a nurse in an ophthalmology clinic. What is the most important management step beyond lubricants and cold compresses?
A. Prescribe topical chloramphenicol for 7 days
B. Exclude her from patient contact for at least 2 weeks and enforce strict hand hygiene
C. Prescribe topical aciclovir as this is likely HSV
D. Prescribe systemic doxycycline as this is likely chlamydial inclusion conjunctivitis
Reveal Answer
Answer: B. Exclude her from patient contact for at least 2 weeks and enforce strict hand hygiene
The clinical picture — bilateral watery conjunctivitis, follicular reaction, tender preauricular node, fever in a healthcare worker — is classic epidemic keratoconjunctivitis (EKC) from adenovirus. The single most critical management step is exclusion from patient contact for at least 2 weeks, because adenovirus is extremely contagious and EKC outbreaks in ophthalmic clinics are well documented. Antibiotics are inappropriate. Aciclovir is for herpes simplex. Doxycycline covers chlamydial infection, which presents differently (subacute, without fever, with a history suggesting urogenital exposure).
Self-Assessment
Having worked through the aetiology, clinical features, differential diagnosis, and management of acute bacterial and viral conjunctivitis, test your understanding against the OP3.2 competency requirements. The key facts you should be able to recall without prompting are: the common bacterial pathogens and their relative severity; the papillary-vs-follicular distinction and what each implies for aetiology; the three-component timing framework for neonatal conjunctivitis; the two adenoviral syndromes (PCF vs EKC), their serotypes, and the timeline of subepithelial infiltrate appearance in EKC; and the management principles — especially when systemic treatment is required. Before attempting the self-test questions, check whether you can articulate not just what the answer is but why: why does gonococcal conjunctivitis require systemic antibiotics when other bacterial forms do not? Why does EKC require exclusion from clinical settings while SAC does not? Why does chlamydial neonatal conjunctivitis require oral erythromycin rather than topical treatment alone? These 'why' questions test your conceptual understanding rather than factual recall, and they represent the level of reasoning that an OSCE examiner expects from a student who can 'describe the management of acute conjunctivitis.'
Self-test questions:
1. A patient has acute red eye with mucopurulent discharge, papillary reaction on eversion, and no preauricular node. What antibiotic do you prescribe and for how long?
2. A patient has bilateral watery red eye with follicular reaction and a tender preauricular node. What antibiotic do you prescribe?
3. At what postnatal age does chlamydial neonatal conjunctivitis typically present, and why does topical treatment alone fail?
4. What specific examination finding in a 'conjunctivitis' patient demands immediate specialist referral?
If you cannot answer question 2 ('none — this is viral, antibiotics are inappropriate'), re-read the management section before your examination.