What is the treatment for conjunctivitis (pink eye)?

Treatment of Conjunctivitis (Pink Eye)

Treatment depends entirely on the underlying cause—viral conjunctivitis requires only supportive care, bacterial conjunctivitis may benefit from topical antibiotics to shorten duration, and allergic conjunctivitis responds best to dual-action antihistamine/mast cell stabilizer drops. 1, 2, 3

Determining the Etiology

The most critical first step is distinguishing between viral, bacterial, and allergic causes, as treatment differs fundamentally:

Bacterial Conjunctivitis

• Key features: Purulent discharge, mattering and adherence of eyelids on waking, lack of itching, no history of prior conjunctivitis 3, 4
• Natural history: Most uncomplicated cases resolve in 1-2 weeks without treatment 3, 5
• Treatment benefit: Topical antibiotics shorten clinical disease duration (62% cured by days 3-5 vs 28% with placebo) and enhance bacterial eradication (71% vs 19% by days 3-5) 5

Viral Conjunctivitis (Most Common Overall)

• Key features: Watery discharge, burning/gritty sensation, variable presentation 1, 3
• Critical point: No proven effective treatment for eradication of adenovirus 1
• Management: Supportive care only—artificial tears, cold compresses, topical antihistamines for symptom relief, oral analgesics 1, 3
• Avoid antibiotics: Indiscriminate antibiotic use can induce toxicity without benefit 1

Allergic Conjunctivitis

• Key feature: Itching is the most consistent sign 3, 6
• Additional features: Bilateral presentation, watery discharge, chemosis, eyelid edema 7, 6

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Treatment Algorithm by Etiology

Bacterial Conjunctivitis

When to treat with antibiotics:

• Always treat: Contact lens wearers (risk of corneal ulcers—requires ophthalmology referral), gonococcal or chlamydial conjunctivitis (requires systemic antibiotics plus topical therapy), severe cases 1, 3, 4
• Consider treating: To allow earlier return to school/work, patient preference for shortened duration 3
• May observe: Uncomplicated cases in otherwise healthy patients, as most are self-limited 3, 7

Antibiotic options:

• Polymyxin-bacitracin ointment: Apply to conjunctival sac 1-3 times daily 8, 5
• Erythromycin ointment: Apply to conjunctival sac, effective for superficial infections 9
• Duration: 7 days typical course 5

Special considerations:

• MRSA concern: Consider conjunctival cultures before starting treatment in severe cases or giant fornix syndrome to guide antibiotic choice 1
• Gonococcal/chlamydial: Requires systemic antibiotics in addition to topical therapy 1, 3

Viral Conjunctivitis

Supportive care only:

• Preservative-free artificial tears (refrigerated for additional cooling relief) 1, 2
• Cold compresses 1
• Topical antihistamines for symptom relief 1
• Oral analgesics 1

When to consider topical corticosteroids:

• Indications: Severe cases with marked chemosis/lid swelling, epithelial sloughing, membranous conjunctivitis, or corneal subepithelial infiltrates causing vision impairment 1
• Agents: Use corticosteroids with poor ocular penetration (fluorometholone, rimexolone, or loteprednol) to minimize IOP elevation and cataract risk 1
• Critical monitoring: Baseline and periodic IOP measurement plus pupillary dilation to evaluate for glaucoma and cataract 1
• Caution: May prolong viral shedding in animal models 1

Infection control:

• Educate patients to minimize contact with others for 10-14 days from symptom onset in the last affected eye 1

Allergic Conjunctivitis

First-line treatment (most effective):

• Dual-action agents: Olopatadine, ketotifen, epinastine, or azelastine—these combine antihistamine and mast cell stabilizing properties for both acute relief and prevention 2, 6
• Non-pharmacologic: Cold compresses, refrigerated preservative-free artificial tears, wearing sunglasses as allergen barrier, avoiding eye rubbing, hypoallergenic bedding, eyelid cleansers 1, 2

Second-line options:

• Mast cell stabilizers alone: Cromolyn, lodoxamide, nedocromil, pemirolast—better for prophylaxis due to slow onset 2
• Topical NSAIDs: Ketorolac for temporary relief of itching 2

Third-line for severe cases:

• Brief topical corticosteroids: Loteprednol etabonate for 1-2 weeks maximum when symptoms inadequately controlled 1, 2
• Monitoring required: Baseline and periodic IOP measurement plus pupillary dilation 1, 2

Fourth-line for refractory cases:

• Topical cyclosporine 0.05%: At least 4 times daily, particularly effective for vernal keratoconjunctivitis, may reduce steroid dependence 2
• Topical tacrolimus: Alternative immunomodulator 1, 2

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Critical Pitfalls to Avoid

What NOT to Do

• Never use punctal plugs in allergic conjunctivitis—they prevent flushing of allergens and inflammatory mediators 1, 2
• Avoid oral antihistamines as primary treatment—they worsen dry eye syndrome and impair the tear film's protective barrier 1, 2
• Avoid chronic vasoconstrictor use—causes rebound vasodilation (conjunctivitis medicamentosa) 1, 2
• Do not use corticosteroids indiscriminately—can prolong adenoviral infections and worsen HSV infections 1
• Avoid antibiotics in viral or allergic conjunctivitis—no benefit and risk of toxicity 1

Corticosteroid Safety

When corticosteroids are necessary:

• Limit duration: 1-2 weeks maximum for acute exacerbations 1, 2
• Choose low-risk agents: Loteprednol, fluorometholone, rimexolone 1, 2
• Mandatory monitoring: Baseline and periodic IOP measurement, pupillary dilation for cataract screening 1, 2
• Taper slowly: Once inflammation controlled 1

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When to Refer to Ophthalmology

• Contact lens wearers with conjunctivitis (evaluate for corneal ulcers) 3, 4
• Severe viral conjunctivitis with corneal involvement or membranous conjunctivitis 1
• Any case requiring corticosteroids beyond 2 weeks 10
• Suspected gonococcal or chlamydial infection 1, 3
• Allergic conjunctivitis unresponsive to topical therapy 2
• Vision changes, severe pain, or pupillary abnormalities (suggests more serious intraocular pathology) 7