What is the appropriate treatment for pink eye (conjunctivitis)?

Treatment for Pink Eye (Conjunctivitis)

For most cases of pink eye, treatment depends entirely on the underlying cause: bacterial conjunctivitis responds to topical antibiotics (though mild cases often resolve without treatment), viral conjunctivitis requires only supportive care, and allergic conjunctivitis needs topical antihistamines with mast-cell stabilizers. 1

Initial Assessment: Determining the Cause

The key to appropriate treatment is distinguishing between bacterial, viral, and allergic etiologies:

• Bacterial conjunctivitis typically presents with mucopurulent discharge causing the eyelids to be matted shut upon waking, lacks itching, and has no prior history of conjunctivitis 2
• Viral conjunctivitis usually presents with watery discharge, preauricular lymphadenopathy, and follicular reaction on the conjunctiva 3, 4
• Allergic conjunctivitis is characterized by intense itching as the most consistent symptom, often with concurrent allergic rhinitis or asthma 5, 2

Bacterial Conjunctivitis Treatment

Mild to Moderate Cases

Observation without antibiotics is acceptable for mild bacterial conjunctivitis in immunocompetent adults, as approximately 64% of cases resolve spontaneously within 6-10 days. 1, 6

However, if you choose to prescribe antibiotics (to shorten symptom duration and allow faster return to work/school):

• Fourth-generation fluoroquinolones (moxifloxacin 0.5% or gatifloxacin) three to four times daily for 5-7 days are preferred first-line agents due to broad gram-positive coverage 1, 6
• Alternative options when fluoroquinolones are unavailable include ofloxacin 0.3%, gentamicin, or tetracycline four times daily 1
• No single topical antibiotic has demonstrated superiority for uncomplicated cases; choice should be based on convenience, cost, and local resistance patterns 1, 6
• Topical antibiotics provide earlier clinical remission (68.2% cure rate versus 55.5% with placebo by days 4-9) 6

Special Populations Requiring Different Management

• Contact lens wearers: Use fourth-generation fluoroquinolones due to risk of Pseudomonas infection 1
• Nursing home residents or suspected MRSA: Consider compounded topical vancomycin if no improvement within 48-72 hours, as MRSA isolates are typically resistant to fluoroquinolones but susceptible to vancomycin 1, 6
• Neonates: Immediate ophthalmology referral is mandatory, as systemic treatment coordinated with a pediatrician is required 6

Sexually Transmitted Disease-Related Conjunctivitis

Gonococcal conjunctivitis requires systemic antibiotic therapy in addition to topical treatment:

• Ceftriaxone 1 g IM single dose plus azithromycin 1 g oral single dose 1
• Adjunctive saline lavage for comfort 1
• Daily ophthalmologic monitoring is mandatory until resolution to prevent corneal perforation 1
• Obtain conjunctival cultures and Gram staining before initiating therapy 1

Chlamydial conjunctivitis mandates systemic therapy:

• Azithromycin 1 g orally single dose OR doxycycline 100 mg twice daily for 7 days in adults 1
• Erythromycin 50 mg/kg/day divided every 4 hours for 14 days in infants 1
• Topical therapy adds no benefit to systemic treatment 1
• Re-evaluation after completion is essential because treatment failure occurs in up to 19% of cases 1
• In children with gonococcal or chlamydial conjunctivitis, consider sexual abuse and arrange appropriate safeguarding measures 1

Alternative When Antibiotics Are Unavailable

• A 1.25% povidone-iodine ophthalmic solution can be used as an effective alternative to topical antibiotics in resource-limited settings 1

Viral Conjunctivitis Treatment

Topical antibiotics provide no clinical benefit in viral conjunctivitis and should be avoided to reduce the risk of adverse effects and antimicrobial resistance 1, 6

Supportive Care Measures

• Refrigerated preservative-free artificial tears four times daily to dilute viral particles and inflammatory mediators 6
• Cold compresses to closed eyelids for comfort 6
• Topical antihistamines for symptomatic relief of itching 6
• Strict hand hygiene with soap and water is essential to prevent transmission 1, 6

Herpes Simplex Virus (HSV) Conjunctivitis

HSV conjunctivitis requires specific antiviral treatment:

• Topical ganciclovir 0.15% gel OR topical trifluridine 1% solution 6
• Oral antivirals (acyclovir, valacyclovir, or famciclovir) may also be used 6
• Topical corticosteroids are absolutely contraindicated in HSV conjunctivitis as they potentiate infection 6

Adenoviral Conjunctivitis

• No proven effective treatment for eradication exists 6, 4
• Topical corticosteroids may be considered only in severe cases with marked chemosis, lid swelling, epithelial sloughing, or membranous conjunctivitis, but require close monitoring for elevated intraocular pressure and cataract 5, 6

Allergic Conjunctivitis Treatment

Second-generation topical antihistamines with mast-cell stabilizing properties are first-line therapy for allergic conjunctivitis 5, 6

Treatment Algorithm

1. First-line: Topical antihistamine/mast-cell stabilizers (e.g., olopatadine, ketotifen) 5, 6
2. Adjunctive measures: Cold compresses, refrigerated artificial tears, sunglasses as allergen barrier, avoiding eye rubbing 5
3. Second-line: If symptoms persist, add a brief 1-2 week course of low side-effect profile topical corticosteroids (fluorometholone, rimexolone, or loteprednol) with monitoring of intraocular pressure 5, 6

Important Considerations

• Chronic use of vasoconstrictor agents can cause rebound vasodilation once stopped 5
• Oral antihistamines may worsen dry eye syndrome and actually exacerbate allergic conjunctivitis 5, 6
• Concomitant use of cooled artificial tears may alleviate coexisting tear deficiency 5

Red-Flag Signs Requiring Immediate Ophthalmology Referral

Any of the following warrants urgent referral 1:

• Decreased visual acuity
• Moderate-to-severe ocular pain
• Profuse purulent discharge (suggesting gonococcal infection)
• Corneal involvement (opacity, infiltrate, ulcer)
• Conjunctival scarring or membrane formation
• Lack of improvement after 3-4 days of appropriate therapy
• Recurrent episodes
• History of HSV eye disease
• Immunocompromised status
• Neonatal conjunctivitis

Follow-Up Strategy

• Routine bacterial conjunctivitis: Return for review in 3-4 days if symptoms have not improved 1
• Gonococcal conjunctivitis: Daily visits until complete resolution 1
• Chlamydial conjunctivitis: Reassess after therapy completion due to potential 19% failure rate 1
• Patients may resume work or school 24-48 hours after initiating antibiotic therapy if symptoms are improving 1, 7

Critical Pitfalls to Avoid

• Never use topical corticosteroids in HSV conjunctivitis without antiviral coverage, as they potentiate viral replication and can cause corneal perforation 6
• Avoid indiscriminate use of topical antibiotics or corticosteroids, as antibiotics can induce toxicity and corticosteroids can prolong adenoviral infections 5, 6
• Do not use combination antibiotic-steroid drops (e.g., Tobradex) unless viral etiology has been definitively excluded, particularly HSV or adenovirus 6
• Delayed referral for gonococcal conjunctivitis can lead to corneal perforation within 24 hours 6
• Failure to consider sexual abuse in children with gonococcal or chlamydial conjunctivitis can have serious consequences 6