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 such as gentamicin, tobramycin, or azithromycin. 1
Treatment Algorithm Based on Severity
Mild Bacterial Conjunctivitis
- Initiate a 5-7 day course of broad-spectrum topical antibiotic applied 4 times daily, which accelerates clinical and microbiological remission by days 2-5, reduces transmissibility, and allows earlier return to school/work 1
- Select the most convenient or least expensive antibiotic as no clinical evidence suggests superiority of any particular agent for mild cases 1
- Preferred first-line options include:
- Alternative option: Povidone-iodine 1.25% ophthalmic solution may be as effective as topical antibiotics when access is limited 1, 2
Moderate to Severe Bacterial Conjunctivitis
Severe disease presents with copious purulent discharge, pain, and marked inflammation 4, 2
- Obtain conjunctival cultures and Gram staining immediately before initiating treatment, especially if gonococcal infection is suspected 1, 4
- Prescribe fluoroquinolones as first-line empiric therapy due to broad-spectrum coverage against common pathogens including Staphylococcus aureus, Streptococcus pneumoniae, Haemophilus influenzae, and Pseudomonas 4
- Fluoroquinolone options:
- Reserve fluoroquinolones for severe infections to preserve effectiveness and prevent resistance 1, 4
Contact Lens Wearers
- Prescribe fluoroquinolones (ofloxacin or ciprofloxacin) due to higher risk of Pseudomonas infection 1, 4
Special Pathogen Considerations
Gonococcal Conjunctivitis
- Systemic antibiotic therapy is mandatory—topical treatment alone is insufficient 1, 4, 2
- Add saline lavage to promote comfort and faster resolution of inflammation 1
- Daily follow-up is mandatory until complete resolution 4
- Hospitalization may be necessary for severe cases and is mandatory for neonatal conjunctivitis 4, 2
Chlamydial Conjunctivitis
- Systemic antibiotic therapy is required—topical therapy alone is inadequate 1, 4, 2
- For neonates: Erythromycin base or ethylsuccinate 50 mg/kg/day divided into 4 doses daily for 14 days, with clinical cure rate of 96% and microbiological cure rate of 97% 1
- For adults: Oral azithromycin (single dose) or tetracycline (7 days) 4
- Consider sexual abuse in children with gonococcal or chlamydial conjunctivitis 1, 2
MRSA Conjunctivitis
- MRSA has been isolated with increasing frequency from bacterial conjunctivitis patients 4, 6
- Compounded topical vancomycin may be required based on microbiology laboratory testing 1, 4
- Approximately 42% of staphylococcal isolates show methicillin resistance with high concurrent fluoroquinolone resistance 4
Follow-Up Protocol
- Instruct patients to return if no improvement after 3-4 days of treatment 1, 4, 2
- Follow-up should include: interval history, visual acuity measurement, and slit-lamp biomicroscopy 1, 2
- For gonococcal conjunctivitis: daily follow-up until complete resolution 4
Critical Pitfalls and Caveats
- Avoid prescribing antibiotics for viral conjunctivitis, which accounts for unnecessary costs and promotes resistance 1
- Do not use topical corticosteroids unless under close ophthalmologic supervision, as they may prolong bacterial shedding and worsen infection 4, 2
- Poor adherence to frequent administration regimens contributes to treatment failure and bacterial resistance 1, 7
- Individual risk factors for fluoroquinolone resistance include: recent fluoroquinolone use, hospitalization, advanced age, and recent ocular surgery 4
When to Refer to Ophthalmology
Immediate referral is indicated for: 1, 4, 2
- Visual loss or decreased visual acuity
- Moderate or severe pain
- Severe purulent discharge
- Corneal involvement (infiltrate, ulceration, or opacity)
- Conjunctival scarring
- Lack of response to therapy after 3-4 days
- Recurrent episodes