Conjunctivitis
Also known as: Pink eye
Inflammation of the conjunctiva: viral (most common, adenovirus, highly contagious), bacterial (Staph, Strep pneumoniae, H. influenzae; gonococcal/chlamydial in neonates/sexually active adults), or allergic (seasonal/perennial).
Viral: watery discharge, often bilateral, follicular reaction, preauricular lymphadenopathy, associated URTI, highly contagious
Bacterial: purulent/mucopurulent discharge, lids stuck together on waking
Allergic: bilateral itching (hallmark), watery discharge, chemosis, associated allergic rhinitis
Neonatal (ophthalmia neonatorum): gonococcal (day 2-5, severe, sight-threatening) vs. chlamydial (day 5-14, more indolent) ; both urgent
Red flags (urgent ophthalmology): reduced visual acuity, significant pain, photophobia, corneal involvement, unilateral in contact lens wearer, trauma history, neonatal presentation.
Clinical, based on discharge pattern.
Swab for culture/PCR if severe, neonatal, recurrent, or refractory.
Fluorescein staining if pain/photophobia (exclude dendritic ulcer/keratitis).
Differentials: keratitis, episcleritis/scleritis, uveitis, dry eye, blepharitis, foreign body, angle-closure glaucoma.
Viral: supportive (cool compresses, lubricants), self-limiting 1-3 weeks, hygiene advice given contagiousness, no antibiotics
Bacterial: often self-limiting; topical chloramphenicol 0.5% drops or 1% ointment qds × 5-7 days speeds resolution/reduces transmission
Allergic: topical antihistamine/mast cell stabilizer (olopatadine bd), oral antihistamines, cold compresses, allergen avoidance
Gonococcal: same-day ophthalmology + systemic ceftriaxone; emergency given perforation risk; neonatal cases require admission, treat mother/partner
Chlamydial: oral azithromycin (adults), erythromycin (neonates), treat as STI (partner treatment, STI screening)
Contact lens wearers with pain: stop lens wear, low threshold for referral (exclude microbial keratitis)
Referral: ophthalmology for red flags, same-day for neonatal/gonococcal, non-resolving/recurrent disease.
