Conjunctivitis Types
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Direct answer
Conjunctivitis is inflammation of the conjunctiva presenting with redness, discharge and discomfort with preserved vision, and is classified as infective (bacterial, viral, chlamydial), allergic or irritant. Bacterial infection gives mucopurulent discharge and matting of lashes, adenoviral infection gives watery discharge with follicles and often preauricular lymphadenopathy, and allergic conjunctivitis gives itching with stringy discharge. Ophthalmia neonatorum, conjunctivitis within the first month of life, is an emergency because gonococcal and chlamydial infection can damage the cornea and cause blindness.
What you must remember
- Bacterial conjunctivitis: acute mucopurulent red eye, maximal in the fornices, with lashes stuck together on waking; common organisms are Staphylococcus aureus, Streptococcus pneumoniae and Haemophilus influenzae; treated with frequent topical broad-spectrum antibiotic drops after lid cleaning, and usually self-limiting.
- Hyperacute (gonococcal) conjunctivitis: copious thick purulent discharge with rapid corneal involvement; needs urgent intensive therapy including systemic treatment, since perforation can occur within days.
- Viral conjunctivitis: adenovirus causes acute follicular conjunctivitis — pharyngoconjunctival fever with fever and pharyngitis, and epidemic keratoconjunctivitis with subepithelial corneal infiltrates; management is supportive with cold compresses and lubricants, with strict hygiene since spread is by fingers and tonometers.
- Allergic conjunctivitis: seasonal and perennial forms cause itching and milky congestion; vernal keratoconjunctivitis of boys and young adults gives giant papillae on the upper tarsal conjunctiva, Trantas dots and shield ulcers; treatment is antihistamine and mast cell stabiliser drops, with short careful topical steroids for severe keratitis.
- Ophthalmia neonatorum: causes by timing — chemical inflammation in the first day or two after prophylaxis, gonococcal at two to five days with profuse purulence, chlamydial in the second week with mucopurulent discharge; investigate with Gram stain and cultures; treat systemically as well as topically, and counsel and treat parents.
- Chronic conjunctivitis: persists from lid margin disease, dry eye, foreign body or drug toxicity; treat the cause rather than escalate antibiotics.
- Danger signs separating conjunctivitis from serious disease: reduced vision, marked photophobia, ciliary congestion, corneal opacity, unilateral severe pain or raised intraocular pressure.
Common confusion
The red eye triad that students must not fumble is conjunctivitis, iritis and acute glaucoma: conjunctivitis has discharge and normal vision with conjunctival injection, iritis has ciliary flush, photophobia and a small sluggish pupil, and acute angle-closure has severe pain, a mid-dilated fixed pupil, corneal oedema and hard globe. Within conjunctivitis, follicles point to viral or chlamydial infection while papillae point to bacterial or allergic disease, and in the newborn the timing of onset is the fastest clue to the organism.
Exam-focused takeaway
In theory, classify conjunctivitis, describe the clinical features of each type and write a full note on ophthalmia neonatorum, a perennial examination favourite. In viva, expect the timing-cause ladder of neonatal conjunctivitis and the differences between follicles and papillae. In the posting, always record vision before examining discharge, look for corneal involvement with fluorescein, and treat the severe vernal and gonococcal cases as vision-threatening rather than routine inflammations.
Frequently asked questions
How do bacterial and viral conjunctivitis differ at the bedside?
Bacterial disease has mucopurulent discharge with lashes stuck together, while viral disease has watery discharge, follicles, often preauricular lymphadenopathy and contagious spread.
What is ophthalmia neonatorum and why is it urgent?
Conjunctivitis developing within the first month of life; gonococcal and chlamydial infection can ulcerate and perforate the newborn cornea, so it demands immediate microbiological work-up and systemic therapy.
What are Trantas dots and shield ulcers?
Trantas dots are collections of eosinophils at the limbus, and shield ulcers are trophic corneal epithelial defects, both characteristic of vernal keratoconjunctivitis.
Which conjunctivitis features suggest a cause other than simple infection?
Reduced vision, severe pain, photophobia, ciliary congestion, corneal opacity, fixed pupil or raised pressure indicate keratitis, uveitis or glaucoma rather than conjunctivitis.
How is epidemic keratoconjunctivitis controlled?
By strict hand hygiene, separate tonometers and instruments, and isolation where possible, since adenovirus spreads by direct contact and contaminated instruments.
What is the treatment of acute bacterial conjunctivitis?
Frequent topical broad-spectrum antibiotic drops, lid cleaning and hygiene measures; uncomplicated cases settle within a week without cultures.