First-Line Therapy for Pink Eye
For acute conjunctivitis, first-line therapy depends entirely on the etiology: viral conjunctivitis requires only supportive care with preservative-free artificial tears and cold compresses; bacterial conjunctivitis is treated with a 5-7 day course of broad-spectrum topical antibiotics such as polymyxin B/trimethoprim or fluoroquinolones; and allergic conjunctivitis responds to topical antihistamines with mast cell-stabilizing properties. 1
Diagnostic Approach to Determine Etiology
Before initiating treatment, you must distinguish between viral, bacterial, and allergic causes based on specific clinical features:
Viral Conjunctivitis (Most Common)
- Watery discharge with a follicular reaction on the inferior tarsal conjunctiva 1
- Preauricular lymphadenopathy, especially with adenoviral infections 1
- Often starts unilateral but becomes sequentially bilateral within days 1
- Concurrent upper respiratory symptoms (rhinorrhea, sore throat, fever) 1
- Marked chemosis and eyelid swelling 1
Bacterial Conjunctivitis
- Mucopurulent or purulent discharge with matted eyelids on waking 1, 2
- Papillary (not follicular) conjunctival reaction 1
- Absence of itching 1
- May be unilateral or bilateral 1
- Can be associated with concurrent otitis media, sinusitis, or pharyngitis in children 1
Allergic Conjunctivitis
- Itching is the hallmark symptom and most consistent distinguishing feature 1, 2
- Bilateral presentation 1
- Watery discharge with mild mucous component 1
- History of atopy, asthma, or eczema 1
- Absence of preauricular lymphadenopathy 1
Treatment by Etiology
Viral Conjunctivitis (Self-Limited, Supportive Care Only)
Viral conjunctivitis requires no antibiotics—only supportive measures. 1
- Preservative-free artificial tears four times daily to dilute viral particles and inflammatory mediators 1, 3
- Cold compresses to reduce conjunctival swelling and improve comfort 1, 3
- Avoid topical antibiotics entirely, as they provide no benefit and may cause toxicity 1, 3
- Patient education about contagiousness: wash hands frequently, avoid sharing towels/pillows, minimize close contact for 10-14 days from symptom onset 1
- Most cases resolve within 5-14 days without treatment 1
Critical pitfall: Indiscriminate use of topical corticosteroids can prolong adenoviral infections and exacerbate herpes simplex virus (HSV) keratitis. 1, 3 Never use steroids without first excluding HSV and ensuring close ophthalmology follow-up. 1
Bacterial Conjunctivitis (Topical Antibiotics)
For mild to moderate bacterial conjunctivitis, prescribe a 5-7 day course of broad-spectrum topical antibiotics. 1, 3
First-Line Antibiotic Options
No single antibiotic has proven superiority, so choose based on convenience, cost, and local resistance patterns: 1, 3
Erythromycin ointment 1
- Often preferred in young children due to ease of application 1
Fluoroquinolones (moxifloxacin 0.5%, levofloxacin, gatifloxacin, ciprofloxacin) three to four times daily 1, 3
Expected outcomes: 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). 6, 3 This allows earlier return to work or school. 1
When to Obtain Cultures
- Neonatal conjunctivitis (mandatory) 1
- Suspected gonococcal infection (severe purulent discharge, marked lid edema) 1
- Failure to improve after 5-7 days of appropriate therapy 1
- Recurrent, severe, or chronic purulent conjunctivitis 1
Special Situations Requiring Systemic Antibiotics
Gonococcal conjunctivitis is a hyperacute, vision-threatening emergency requiring immediate systemic therapy: 7, 1
- Ceftriaxone 250 mg IM single dose PLUS azithromycin 1 g oral single dose 3
- Daily ophthalmology follow-up until resolution 1, 3
- Can cause corneal perforation within 24 hours if untreated 1, 3
Chlamydial conjunctivitis requires systemic treatment because >50% of infants have concurrent infection at other sites: 1, 3
- Azithromycin 1 g oral single dose OR doxycycline 100 mg oral twice daily for 7 days 3
- Evaluate and treat sexual partners 1, 3
- Consider sexual abuse in preadolescent children 3
Allergic Conjunctivitis (Topical Antihistamines)
First-line treatment is topical antihistamines with mast cell-stabilizing properties. 1, 3
- Olopatadine or ketotifen drops 1, 3
- Adjunctive measures: cold compresses, refrigerated preservative-free artificial tears, sunglasses as allergen barrier 1, 3
- Avoid eye rubbing 1
- For refractory cases, consider a brief 1-2 week course of low-potency topical corticosteroids (fluorometholone, loteprednol) with IOP monitoring 1, 3
Red-Flag Findings Requiring Urgent Ophthalmology Referral
Do not treat empirically if any of the following are present—refer immediately: 1, 3
- Visual loss or decreased vision 1
- Moderate to severe pain (beyond mild irritation) 1
- Corneal involvement (opacity, infiltrate, ulcer) 1
- Severe purulent discharge suggesting gonococcal infection 1
- Conjunctival scarring or pseudomembrane formation 1
- History of HSV eye disease 1
- Immunocompromised state 1
- Recent ocular surgery or trauma 1
- Contact lens wear with conjunctivitis (risk of bacterial keratitis) 1
- Lack of response to therapy after 5-7 days 1
Common Pitfalls to Avoid
- Never prescribe antibiotics for viral conjunctivitis—they cause unnecessary toxicity and promote resistance. 1, 3
- Never use topical corticosteroids without excluding HSV and ensuring close ophthalmology follow-up, as they can exacerbate HSV infections, prolong adenoviral shedding, and cause elevated IOP and cataracts. 1, 3
- Do not miss gonococcal conjunctivitis—it requires immediate systemic antibiotics and can cause corneal perforation. 1, 3
- Avoid chronic use of topical vasoconstrictors—they cause rebound vasodilation. 3
- Discard multi-dose eye drop containers if they contact the ocular surface to prevent cross-contamination. 1