Conjunctivitis and red eye — branching viva

Opening question

Examiner: Take me through this child. What is the diagnosis, and what is your frame for managing it? [1]

Candidate: The most likely diagnosis is viral conjunctivitis, most often adenoviral. The clear watery discharge, follicles on the tarsal conjunctiva, the tender preauricular lymph node and the recent runny nose are the classic picture, and the sick classmate fits an outbreak. My frame is three-layered: first, confirm that this is conjunctivitis and not a dangerous red eye, by screening for pain, photophobia, reduced vision and the other red flags; second, match the treatment to the cause, which for a viral cause is supportive care and hygiene; and third, give clear safety-net and school advice. Because the child is well with normal vision and no pain, this is a community-managed case. [1] [6]

Examiner: How do you classify conjunctivitis, and which form is dangerous? [1]

Candidate: The three common forms are bacterial, viral and allergic. Bacterial conjunctivitis produces purulent or mucopurulent discharge with crusted lashes; viral conjunctivitis produces watery discharge with follicles and a preauricular node; and allergic conjunctivitis is dominated by itching, with cobblestone papillae in an atopic child. The dangerous forms are not these but the causes of a red eye that look like conjunctivitis and are not — bacterial keratitis in a contact-lens wearer, herpes simplex dendritic keratitis, iritis and acute glaucoma — plus, in the newborn, gonococcal ophthalmia neonatorum that can perforate the cornea within hours. [1] [5]

Branch 1 — the red-eye triage

Examiner: What features would change your management to urgent ophthalmology referral? [5]

Candidate: The red-eye red flags: pain, photophobia, reduced vision, a foreign-body sensation, contact-lens use, trauma, ciliary flush — a ring of redness concentrated around the cornea — a corneal opacity or ulcer, and an abnormal pupil. Any of these points to keratitis, iritis or uveitis, acute glaucoma, corneal abrasion or a retained foreign body rather than conjunctivitis. Conjunctivitis causes discomfort and grittiness, not true pain or visual loss. I would perform fluorescein staining to look for a corneal defect and refer urgently. [5]

Examiner: A 15-year-old contact-lens wearer presents with a painful red eye and a corneal infiltrate. What do you do? [5]

Candidate: This is bacterial keratitis with a corneal ulcer until proven otherwise, which is a sight-threatening emergency. I remove the lens, advise the adolescent to stop wearing contact lenses, do not patch the eye, and refer the same day to ophthalmology for corneal scraping and intensive topical antibiotic therapy. Treating this as conjunctivitis with a chloramphenicol drop is the classic error that blinds, and the contact lens is the clue that must never be missed. [5]

Branch 2 — management of the common forms

Examiner: What treatment will you give this child with viral conjunctivitis? [6]

Candidate: Viral conjunctivitis is self-limiting and resolves over one to two weeks. The management is supportive: lubricating drops and cold compresses for comfort, with strict hygiene to limit spread — frequent hand washing, not sharing towels or pillows, and avoiding eye rubbing. Because adenoviral conjunctivitis is highly contagious, I advise exclusion from school, childcare and swimming pools until the discharge has settled. Topical antibiotics do not help a viral cause. I give a clear safety-net for pain, photophobia or reduced vision. [6]

Examiner: When would you use a topical antibiotic, and what does the evidence say? [3]

Candidate: For severe, persistent or socially-disruptive bacterial conjunctivitis, I would give a five to seven day course of topical chloramphenicol (0.5% drops or 1% ointment), with fusidic acid as the alternative. The Cochrane review found that topical antibiotics improve the early cure rate at days two to five compared with placebo, but that this benefit is no longer significant by day six to ten, when most cases have resolved regardless of treatment. So I reserve topical antibiotics for severe or persistent disease rather than prescribing for every red eye, in keeping with antibiotic stewardship. [3]

Branch 3 — allergic conjunctivitis

Examiner: How would your management change if this were an itchy, bilateral eye in a child with hayfever? [8]

Candidate: Then the diagnosis is allergic conjunctivitis, which is IgE-mediated and dominated by itching. The management is layered: allergen avoidance, cold compresses for symptom relief, and a topical antihistamine with mast-cell stabiliser such as olopatadine, which addresses both the trigger and the mediator. I add an oral antihistamine such as cetirizine for the systemic atopic symptoms. The chronic, sight-threatening forms — vernal and atopic keratoconjunctivitis — need ophthalmology referral, because they can scar the cornea. [8]

Branch 4 — the neonate

Examiner: Now picture a 10-day-old with mucopurulent conjunctivitis and a staccato cough. What is the diagnosis and how do you manage it? [11]

Candidate: The onset at day 10 (within the day 5 to 14 window) with mucopurulent discharge and a staccato cough is chlamydial ophthalmia neonatorum, the commonest cause, with evolving chlamydial pneumonia. I take conjunctival swabs for Gram stain, culture and chlamydia testing, and I treat systemically — oral erythromycin 50 mg per kilogram per day in four divided doses for 14 days — because topical treatment does not eradicate nasopharyngeal carriage or prevent the pneumonia. A single course may need repeating, and I screen and treat the mother and her partner for sexually-transmitted infection. [11] [9]

Examiner: What if it were a 3-day-old with profuse purulent discharge and lid oedema? [9]

Candidate: That is gonococcal ophthalmia neonatorum, which appears at day 2 to 5 and can perforate the cornea within hours. I admit the infant, take conjunctival swabs for Gram stain and culture, and start systemic therapy — intramuscular or intravenous ceftriaxone, avoiding ceftriaxone in the jaundiced or calcium-infused neonate when cefotaxime is the alternative — with frequent saline irrigation of the eye and urgent ophthalmology review. The mother and her partner are screened and treated. [9]

Wrap

Examiner: Summarise the conjunctivitis and red-eye stance in one sentence. [1]

Candidate: Triage the red eye before you treat it — screen for the red flags that point to keratitis, iritis, glaucoma, abrasion or foreign body and refer urgently — then match the treatment to the cause: supportive care and hygiene for the virus, a short topical course for severe bacteria with the Cochrane-modest-benefit caveat in mind, antihistamine-mast-cell stabiliser for allergy, and culture with systemic therapy for the newborn — because the red eye that looks like conjunctivitis but is not is the one that costs sight. [1] [9]