What is the appropriate treatment for pink eye (conjunctivitis) in a typical adult without known drug allergies?

Treatment for Pink Eye (Conjunctivitis)

For typical adult bacterial conjunctivitis without complications, prescribe a topical fluoroquinolone (moxifloxacin 0.5% or ciprofloxacin 0.3%) three to four times daily for 5-7 days, though observation without antibiotics is also acceptable since most cases are self-limited. 1, 2

Determining the Etiology

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

Bacterial conjunctivitis presents with:

• Mucopurulent discharge with eyelids matted shut upon waking 3, 4
• Lack of itching 4
• Unilateral or bilateral presentation 1
• More common in children 3

Viral conjunctivitis presents with:

• Watery discharge 3, 5
• Follicular reaction on conjunctiva 1
• Preauricular lymphadenopathy 1
• More common in adults 3

Allergic conjunctivitis presents with:

• Severe itching (most consistent sign) 4, 6
• Mucoid discharge, chemosis, eyelid edema 5
• History of allergen exposure 6

Treatment by Etiology

Mild to Moderate Bacterial Conjunctivitis

You have two evidence-based options:

Option 1: Observation without antibiotics 2

• Approximately 64% of cases resolve spontaneously by days 6-10 1, 2
• Valid first-line approach in immunocompetent adults 2

Option 2: Topical antibiotics 1, 2

• Shortens symptom duration by 2-5 days 2
• Provides earlier clinical remission on days 2-5 1
• Reduces transmissibility and allows earlier return to work 1, 2

Specific antibiotic recommendations:

• Moxifloxacin 0.5% three times daily for 5-7 days (preferred for superior gram-positive coverage including some MRSA strains) 1
• Ciprofloxacin 0.3% one to two drops every 2 hours while awake for 2 days, then every 4 hours while awake for 5 days 7
• Alternative options: gentamicin, tetracycline, or ofloxacin 0.3% four times daily if fluoroquinolones unavailable 1
• No single antibiotic shows superiority, so choose based on convenience and cost 1, 2

Severe Bacterial Conjunctivitis

Immediate actions required: 1, 2

• Obtain conjunctival cultures and Gram stain before starting antibiotics 1
• Initiate empiric broad-spectrum topical fluoroquinolone 2
• Consider MRSA coverage (compounded topical vancomycin may be needed if unresponsive to fluoroquinolones within 48-72 hours) 1

Gonococcal Conjunctivitis

This is a medical emergency requiring systemic antibiotics: 8, 1, 2

• Ceftriaxone 250 mg IM single dose PLUS azithromycin 1 g oral single dose 1
• Add topical antibiotics and saline lavage 8
• Daily monitoring until resolution to prevent corneal perforation 8, 1
• Evaluate for concurrent urethritis, cervicitis, or pelvic inflammatory disease 2
• Treat sexual partners 8

Chlamydial Conjunctivitis

Systemic antibiotics are mandatory: 8, 1, 2

• Azithromycin 1 g oral single dose OR doxycycline 100 mg oral twice daily for 7 days 1
• No benefit from adding topical antibiotics 8
• Re-evaluate after treatment (failure rate up to 19%) 8
• Treat sexual partners 8
• More than 50% of infants have infection at other sites (nasopharynx, lungs), requiring systemic therapy 8

Viral Conjunctivitis

Supportive care only—no antibiotics: 1, 3

• Refrigerated preservative-free artificial tears four times daily 1
• Cold compresses 1, 3
• Topical antihistamines for symptomatic relief 1
• Strict hand hygiene with soap and water to prevent transmission 1, 2

For HSV conjunctivitis specifically:

• Topical ganciclovir 0.15% gel OR trifluridine 1% solution 1
• Add oral antivirals (acyclovir, valacyclovir, or famciclovir) 1
• Never use topical corticosteroids without antiviral coverage—they potentiate HSV infection 1

Allergic Conjunctivitis

First-line treatment: 1

• Second-generation topical antihistamines with mast cell-stabilizing properties 1, 4
• Cold compresses, refrigerated artificial tears 1
• Sunglasses as allergen barrier 1

Second-line if symptoms persist:

• Brief 1-2 week course of low side-effect profile topical corticosteroids (fluorometholone, rimexolone, or loteprednol) 1
• Monitor intraocular pressure and for cataract formation 1

Red Flags Requiring Immediate Ophthalmology Referral

Do not treat empirically—refer urgently if: 8, 1, 2

• Visual loss or decreased vision 8, 1, 2
• Moderate to severe pain 8, 1, 2
• Corneal involvement (opacity, infiltrate, ulcer) 8, 1, 2
• Severe purulent discharge suggesting gonococcal infection 8, 1, 2
• Conjunctival scarring or membrane formation 8, 2
• Lack of response to appropriate therapy after 3-4 days 8, 1
• Recurrent episodes 8, 2
• History of HSV eye disease 8, 1
• Immunocompromised state 8, 1, 3
• Neonatal conjunctivitis 1, 3

Critical Pitfalls to Avoid

Never prescribe systemic antibiotics for uncomplicated bacterial conjunctivitis 1, 2

• Oral antibiotics cannot reach therapeutic levels in the conjunctiva 1
• Reserved exclusively for gonococcal and chlamydial infections 1

Never use topical corticosteroids without ruling out HSV 1, 2

• Steroids potentiate HSV infection and can cause corneal perforation 1
• Steroids prolong adenoviral infections 1

Avoid indiscriminate antibiotic use in viral conjunctivitis 1

• No benefit, risk of toxicity and resistance 1

Discontinue contact lens wear during active conjunctivitis 2

Follow-Up Strategy

For routine bacterial conjunctivitis: 8, 1

• Return if no improvement in 3-4 days 8, 1
• Patients may return to work/school after 24-48 hours of antibiotics if improving 2
• Complete resolution typically occurs within 7-10 days 2

For gonococcal conjunctivitis: 8, 1

• Daily visits until complete resolution 8, 1

For chlamydial conjunctivitis: 8, 1

• Re-evaluate after treatment completion due to 19% failure rate 8, 1

Special Populations

Contact lens wearers: 1

• Higher risk of Pseudomonas infection 1
• Require fluoroquinolone coverage (ciprofloxacin or ofloxacin) 1

Nursing home residents: 8, 1

• Increased MRSA colonization 8
• Consider compounded topical vancomycin if unresponsive to fluoroquinolones 1

Children with gonococcal or chlamydial infection: 8, 1

• Consider sexual abuse 8, 1