What is the treatment for bacterial conjunctivitis?

Treatment of Bacterial Conjunctivitis

For mild bacterial conjunctivitis, prescribe a 5-7 day course of broad-spectrum topical antibiotic applied 4 times daily, choosing the most convenient or least expensive option since no evidence shows superiority of any particular agent. 1, 2

Initial Treatment Approach

Mild Bacterial Conjunctivitis

• Prescribe any broad-spectrum topical antibiotic for 5-7 days, 4 times daily 1, 2
• Acceptable first-line options include:
  • Polymyxin B/trimethoprim 1
  • Polymyxin B/bacitracin 3
  • Tobramycin 1
  • Erythromycin 1
  • Azithromycin (1 drop twice daily for 2 days, then once daily for 5 days) 4
• Reserve fluoroquinolones (moxifloxacin, ofloxacin, ciprofloxacin) for moderate-to-severe cases with copious purulent discharge, pain, and marked inflammation, or for contact lens wearers at higher risk for Pseudomonas infection 1, 5
• Alternative when antibiotic access is limited: povidone-iodine 1.25% ophthalmic solution may be equally effective 1, 2

The rationale for this approach is that topical antibiotics accelerate clinical and microbiological remission by days 2-5, reduce transmissibility, and allow earlier return to school/work, even though mild bacterial conjunctivitis is self-limited 1, 2, 3. The American Academy of Ophthalmology explicitly states no clinical evidence suggests superiority of any particular antibiotic for mild cases 1.

Moderate-to-Severe Bacterial Conjunctivitis

• Obtain conjunctival cultures and Gram staining before starting treatment 1, 6, 2
• Start empiric fluoroquinolone therapy (moxifloxacin 3 times daily for 7 days) 5
• Adjust antibiotics based on culture results 2
• For MRSA infections, vancomycin may be required 1, 2

Special Situations Requiring Systemic Therapy

Gonococcal Conjunctivitis

• Requires systemic antibiotic therapy, not topical treatment alone 1, 6, 2
• Add saline lavage for comfort and faster resolution 1
• Daily follow-up until resolution 2
• If corneal involvement present, treat as bacterial keratitis 2
• Hospitalization may be necessary for severe cases and is mandatory for neonates 1

Chlamydial Conjunctivitis

• Requires systemic antibiotic therapy 1, 6, 2
• For neonates: erythromycin base or ethylsuccinate 50 mg/kg/day divided into 4 doses for 14 days (clinical cure rate 96%, microbiological cure 97%) 1
• No evidence supports adding topical therapy beyond systemic treatment 1
• Follow-up evaluation is critical as treatment failure occurs in up to 19% of cases 2
• In children, consider sexual abuse as a possible cause 1, 2

Follow-Up and Red Flags

When to Reassess

• Instruct patients to return if no improvement after 3-4 days of treatment 1, 6, 2
• At follow-up: perform interval history, visual acuity measurement, and slit-lamp biomicroscopy 1, 6

When to Refer to Ophthalmology

Refer immediately for: 1, 6

• Visual loss
• Moderate or severe pain
• Severe purulent discharge
• Corneal involvement
• Conjunctival scarring
• Lack of response to therapy
• Recurrent episodes
• Neonatal conjunctivitis (especially HSV, which can be life-threatening) 6

Critical Pitfalls to Avoid

• Do not prescribe antibiotics for viral conjunctivitis - this accounts for unnecessary costs and promotes resistance 1
• Avoid topical corticosteroids unless under close ophthalmologic supervision - they may prolong bacterial shedding and worsen infection 6
• Do not use topical therapy alone for gonococcal or chlamydial conjunctivitis - systemic treatment is mandatory 1, 6, 2
• Advise patients not to wear contact lenses during active infection 6, 5, 4
• Counsel on hygiene measures: frequent handwashing and avoiding sharing personal items 6
• Be aware of increasing bacterial resistance, particularly MRSA 1, 6, 2