How should pink eye (conjunctivitis) be managed?

Management of Pink Eye (Conjunctivitis)

Determine the Etiology First—Treatment Depends Entirely on the Cause

The most critical step is distinguishing viral, bacterial, and allergic conjunctivitis, because viral cases require only supportive care, bacterial cases may benefit from topical antibiotics in moderate-to-severe presentations, and allergic cases respond to antihistamines with mast-cell stabilizers. 1

Key Clinical Features to Differentiate Etiology

Viral conjunctivitis:

• Watery discharge with follicular reaction on inferior tarsal conjunctiva 1
• Preauricular lymphadenopathy (especially with adenovirus) 1
• Often starts unilateral but becomes sequentially bilateral 1
• May have concurrent upper respiratory infection 1
• Subconjunctival hemorrhages, chemosis, and marked eyelid swelling can occur 1

Bacterial conjunctivitis:

• Mucopurulent or purulent discharge with matted eyelids on waking 1, 2
• Papillary (not follicular) conjunctival reaction 1
• Can be unilateral or bilateral 1
• Preauricular lymphadenopathy less common unless hypervirulent organisms (gonococcus) 1
• May be associated with concurrent otitis media, sinusitis, or pharyngitis in children 1

Allergic conjunctivitis:

• Itching is the most consistent and distinguishing feature 1, 2
• Bilateral presentation 1
• Watery discharge with mild mucous component 1
• Often seasonal or perennial depending on allergen exposure 1
• May have concurrent allergic rhinitis or asthma 1
• Absence of preauricular lymphadenopathy and matted eyelids 1

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Management by Etiology

Viral Conjunctivitis: Supportive Care Only

Do not prescribe antibiotics for viral conjunctivitis—they provide no benefit, cause unnecessary toxicity, and contribute to antimicrobial resistance. 1, 3

Supportive measures:

• Preservative-free artificial tears (refrigerated) four times daily to dilute viral particles and inflammatory mediators 1, 3
• Cold compresses to reduce conjunctival swelling and improve comfort 1, 3
• Topical antihistamines (second-generation) for symptomatic relief of irritation 1

Patient education on contagiousness:

• Minimize contact with others for 10–14 days from symptom onset 1
• Strict hand hygiene with soap and water, especially after touching eyes 1, 3
• Avoid sharing towels, pillows, or other personal items 1, 3
• Avoid rubbing eyes to prevent exacerbation and spread 1
• Causative virus can remain infectious on dry surfaces for up to 28 days 1

When to consider topical corticosteroids (with extreme caution):

• Only in severe adenoviral cases with marked chemosis, severe lid swelling, epithelial sloughing, or membranous conjunctivitis 1, 3
• Requires close ophthalmology follow-up with regular monitoring of intraocular pressure and pupillary dilation for cataract 1, 3
• Use low side-effect profile steroids (fluorometholone, rimexolone, or loteprednol) at minimum effective dose 1
• Never use corticosteroids in herpes simplex virus (HSV) conjunctivitis without antiviral coverage—they potentiate viral replication and can cause corneal perforation 1, 3

Special consideration for HSV conjunctivitis:

• Usually presents unilaterally with vesicular rash or ulceration of eyelids and dendritic epithelial keratitis 1
• Topical ganciclovir 0.15% gel three to five times daily or trifluridine 1% solution five to eight times daily 3
• Add oral antivirals (acyclovir, valacyclovir, or famciclovir) 3

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Bacterial Conjunctivitis: Topical Antibiotics for Moderate-to-Severe Cases

Mild bacterial conjunctivitis is self-limited and resolves spontaneously in 64% of cases by days 6–10, but topical antibiotics shorten duration (68% cure by days 4–9 vs. 55% with placebo) and allow earlier return to work or school. 3, 4

For moderate-to-severe bacterial conjunctivitis, prescribe a 5–7 day course of broad-spectrum topical antibiotic: 1, 3

• Topical moxifloxacin 0.5% three times daily is often preferred due to superior gram-positive coverage, including some MRSA strains 1, 3
• No single antibiotic has demonstrated superiority, so choice can be based on dosing convenience and cost 1, 3
• Alternative options: gentamicin, tetracycline, ofloxacin 0.3% four times daily, erythromycin ointment, polymyxin B/trimethoprim drops 1, 3

When to obtain cultures before starting antibiotics:

• Suspected gonococcal infection (severe purulent discharge, marked lid edema, sexually active adult or neonate 3–5 days postpartum) 1, 3
• Suspected MRSA (nursing home resident, recent hospitalization, failure to respond to fluoroquinolones within 48–72 hours) 1, 3
• Neonatal conjunctivitis 1, 3
• Recurrent, severe, or chronic purulent conjunctivitis 1
• Failure to improve after initial 5–7 day course 1

Special situations requiring systemic antibiotics:

Gonococcal conjunctivitis (requires urgent ophthalmology referral):

• Systemic therapy is mandatory—topical antibiotics alone are insufficient 1, 3
• Adult: ceftriaxone 250 mg IM single dose plus azithromycin 1 g oral single dose 3
• Neonate: ceftriaxone 25–50 mg/kg IV or IM single dose (max 125 mg) 3
• Daily monitoring until resolution to prevent corneal perforation 1, 3
• Treat sexual partners 1, 3

Chlamydial conjunctivitis:

• Systemic therapy required because >50% of infants have concurrent infection at other sites (nasopharynx, genital tract, lungs) 1, 3
• Adult: azithromycin 1 g oral single dose or doxycycline 100 mg oral twice daily for 7 days 3
• Neonate: erythromycin base or ethylsuccinate 50 mg/kg/day oral divided into 4 doses for 14 days 3
• Re-evaluate after treatment completion (19% failure rate) 3
• Treat sexual partners 1, 3
• Consider sexual abuse in preadolescent children with gonococcal or chlamydial conjunctivitis 3

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Allergic Conjunctivitis: Topical Antihistamines with Mast-Cell Stabilizers

First-line treatment is topical antihistamines with mast-cell stabilizing activity (e.g., olopatadine or ketotifen). 1, 3

Adjunctive environmental measures:

• Wear sunglasses as a physical barrier to airborne allergens 1, 3
• Use cold compresses and refrigerated artificial tears 1, 3
• Avoid eye rubbing 1
• Avoid known allergens and consider hypoallergenic bedding 1

For refractory cases:

• Brief 1–2 week course of low side-effect profile topical corticosteroids (fluorometholone, rimexolone, or loteprednol) 1, 3
• Monitor intraocular pressure and perform periodic pupillary dilation if corticosteroids are used 1, 3

Avoid chronic use of topical vasoconstrictors—they cause rebound vasodilation after discontinuation. 1, 3

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Red-Flag Symptoms Requiring Urgent Ophthalmology Referral (Within 24 Hours)

Refer immediately if any of the following are present: 1, 3, 5

• Visual loss or decreased vision
• Moderate or severe pain (beyond mild irritation)
• Severe purulent discharge (possible gonococcal infection)
• Corneal involvement (opacity, infiltrate, ulcer, or haze)
• Conjunctival scarring
• Lack of response to therapy after 3–4 days
• Recurrent episodes
• History of herpes simplex virus eye disease
• Immunocompromised state
• Neonatal conjunctivitis (requires systemic treatment coordinated with pediatrician)
• Recent ocular surgery

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Follow-Up Strategy

For viral conjunctivitis:

• Patients should return if symptoms persist beyond 2–3 weeks or worsen 1
• Severe cases (with corticosteroids) require re-evaluation within 1 week 1

For bacterial conjunctivitis:

• Return in 3–4 days if no improvement 1, 3
• Gonococcal: daily visits until resolution 1, 3
• Chlamydial: re-evaluate after treatment completion 1, 3

For allergic conjunctivitis:

• Follow-up based on severity and response to treatment 1

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Common Pitfalls to Avoid

• Do not use topical antibiotics indiscriminately for viral conjunctivitis—they provide no benefit and may cause toxicity 1, 3
• Do not use topical corticosteroids without close ophthalmology follow-up—they can prolong adenoviral infections, worsen HSV infections, and cause elevated intraocular pressure and cataracts 1, 3
• Do not use topical corticosteroids in HSV conjunctivitis without antiviral coverage—they potentiate infection 1, 3
• Do not miss gonococcal conjunctivitis—it can cause corneal perforation within 24 hours and requires immediate systemic treatment 1, 3
• Do not use oral antibiotics for routine bacterial conjunctivitis—they are reserved exclusively for gonococcal and chlamydial infections 3
• Do not allow contact lens wear during any form of infectious conjunctivitis 1
• Do not forget to educate patients about contagiousness—inadequate counseling leads to community spread 1