What is the appropriate treatment for conjunctivitis, including bacterial, viral, and allergic etiologies, and what special considerations apply for contact‑lens wearers?

Treatment of Conjunctivitis

Treatment of conjunctivitis must be tailored to the specific etiology—viral, bacterial, or allergic—with contact lens wearers requiring immediate lens removal and more aggressive management due to increased risk of keratitis. 1, 2

Immediate Assessment and Triage

Key Diagnostic Features to Identify Etiology

Bacterial conjunctivitis presents with:

• Mucopurulent discharge with eyelids matted shut upon waking 3, 4
• Lack of itching 3
• No history of prior conjunctivitis 3
• More common in children 4, 5

Viral conjunctivitis presents with:

• Watery discharge 4
• Variable signs and symptoms at presentation 3
• More common in adults 4
• Most common overall cause of infectious conjunctivitis 3

Allergic conjunctivitis presents with:

• Itching as the most consistent sign 3, 6
• Bilateral eyelid edema, conjunctival injection, chemosis 1
• Watery discharge with mild mucous component 1
• History of allergen exposure 6

Treatment by Etiology

Viral Conjunctivitis

Viral conjunctivitis requires only supportive care, as it is self-limited and topical antibiotics should be avoided. 3, 4

• Apply cold compresses for symptomatic relief 1, 4
• Use preservative-free artificial tears 1, 4
• Consider topical antihistamine drops for symptomatic relief 4
• Emphasize strict hand hygiene to prevent transmission 4
• Disinfect tonometer tips with 1:10 sodium hypochlorite solution or use disposable tips 1
• Consider triaging patients to a dedicated "red-eye room" during active epidemics 1

Bacterial Conjunctivitis

Most uncomplicated bacterial conjunctivitis is self-limited, resolving in 1-2 weeks without treatment, though topical antibiotics shorten duration and allow earlier return to work or school. 3, 4

• Delayed antibiotic prescribing (providing prescription but instructing patient to wait 2-3 days before filling) achieves similar symptom control as immediate prescribing 4
• No single topical antibiotic has demonstrated superiority over others 1
• Critical exceptions requiring immediate systemic antibiotics:
  • Gonococcal conjunctivitis (sexually active adults or neonates 3-5 days postpartum with severe bilateral purulent discharge) requires aggressive systemic plus topical therapy 1, 6
  • Chlamydial conjunctivitis requires systemic treatment in addition to topical antibiotics 3, 6

Allergic Conjunctivitis

Topical antihistamines with mast cell-stabilizing activity are the treatment of choice for allergic conjunctivitis. 1, 4

First-Line Management:

• Recommend sunglasses as barrier to airborne allergens 1
• Apply cold compresses and refrigerated artificial tears 1
• Advise avoiding eye rubbing and known allergens 1
• Use hypoallergenic bedding, eyelid cleansers, frequent clothes washing, and showering before bedtime 1

Pharmacologic Treatment:

• Mild cases: Over-the-counter topical antihistamine/vasoconstrictor agents or second-generation topical H1-receptor antagonists 1
• Chronic/recurrent cases: Mast-cell stabilizers or combination antihistamine/mast-cell stabilizers 1
• Severe cases: Add brief 1-2 week course of low side-effect profile topical corticosteroids 1
• Refractory cases: Consider topical cyclosporine or tacrolimus 1

Important caveat: Chronic use of vasoconstrictor agents causes rebound vasodilation upon discontinuation 1. Oral antihistamines may worsen dry eye syndrome 1.

Special Considerations for Contact Lens Wearers

Contact lens wearers with any form of conjunctivitis must immediately remove lenses and discontinue wear until complete corneal normalization, as they face significantly higher risk of bacterial keratitis. 2

Critical Red Flags in Contact Lens Wearers:

• Moderate to severe pain suggests bacterial keratitis or Acanthamoeba keratitis, especially with history of swimming, showering, or hot tub use while wearing contacts 2
• Unilateral presentation with pain is more concerning for infectious keratitis than bilateral allergic/viral conjunctivitis 2

Treatment Approach:

• All contact lens wearers with bacterial conjunctivitis require topical antibiotics (unlike non-wearers where observation may be appropriate) 2
• For mild contact lens-related keratoconjunctivitis with punctate epithelial keratitis, pannus, and neovascularization: prescribe 1-2 week course of topical corticosteroids 2
• Consider longer-term topical cyclosporine 0.05% for persistent inflammation 2

Follow-Up Management After Resolution:

• Review contact lens fit, type, and wearing schedule comprehensively 2
• Switch to daily disposable lenses when possible 2
• Use preservative-free lens care systems 2
• Reduce daily wearing time 2
• Strongly discourage overnight wear (increases corneal infection risk fivefold) 2
• Educate on water avoidance: never swim, shower, use hot tubs, or wash hair while wearing contacts 2
• Instruct never to rinse lenses or cases with tap water, bottled water, or homemade saline 2
• Replace lens cases every 3 months minimum 2

When to Refer to Ophthalmology

Immediate ophthalmology referral is indicated for: 4

• Neonatal conjunctivitis
• Severe pain or decreased vision
• Recent ocular surgery
• Vesicular rash on eyelids or nose (herpes zoster)
• History of rheumatologic disease
• Immunocompromised state
• Contact lens wearers with moderate to severe pain (rule out Acanthamoeba keratitis) 2

Common Pitfalls to Avoid

• Do not use topical corticosteroids for viral conjunctivitis (prolongs adenoviral infections and worsens HSV infections) 1
• Do not use topical corticosteroids for bacterial conjunctivitis without ophthalmology supervision 1
• Do not allow contact lens wearers to resume wear prematurely before complete resolution 2
• Do not miss gonococcal or chlamydial conjunctivitis in sexually active adults or neonates, as these require systemic antibiotics 1, 6
• Do not fail to examine the cornea with fluorescein staining in contact lens wearers to rule out keratitis 2