What is the treatment for conjunctivitis (pink eye) in adults?

Treatment of Pink Eye (Conjunctivitis) in Adults

For mild bacterial conjunctivitis in adults, prescribe a 5-7 day course of broad-spectrum topical antibiotic (such as erythromycin, polymyxin B/trimethoprim, or fluoroquinolones), which accelerates resolution and reduces transmission, though most cases are self-limited. 1

Determining the Type of Conjunctivitis

The first critical step is distinguishing between viral, bacterial, and allergic causes, as treatment differs substantially:

Bacterial Conjunctivitis

• Presentation: Mucopurulent discharge with eyelids matted shut upon waking, lack of itching, no prior history of conjunctivitis 2, 3
• Natural history: Most uncomplicated cases resolve in 1-2 weeks without treatment; bacteria clear in 7 days naturally versus 5 days with antibiotics 4, 3

Viral Conjunctivitis

• Presentation: Watery discharge, more common in adults, highly contagious 2, 3
• Treatment: Supportive care only—artificial tears, cold compresses, antihistamine drops for symptom relief 2, 3
• Critical: Do NOT prescribe antibiotics for viral conjunctivitis, as this promotes resistance and adds unnecessary cost 1

Allergic Conjunctivitis

• Presentation: Itching is the most consistent sign, watery discharge 3, 5
• Treatment: Topical antihistamines with mast cell-stabilizing activity are first-line 4, 3

Treatment Algorithm for Bacterial Conjunctivitis

Mild Cases (Most Common)

• Choose the most convenient or least expensive topical antibiotic, as no evidence demonstrates superiority of any particular agent 1
• Recommended options: Erythromycin ointment, polymyxin B/trimethoprim drops, gentamicin, tetracycline, or ofloxacin 1
• Dosing for erythromycin: Apply approximately 1 cm ribbon to affected eye(s) up to 6 times daily depending on severity 6
• Duration: 5-7 day course 1
• Alternative: Povidone-iodine 1.25% ophthalmic solution may be as effective when antibiotic access is limited 1

Moderate to Severe Cases

• Obtain conjunctival cultures and Gram staining BEFORE starting treatment 1
• Reserve fluoroquinolones (moxifloxacin, gatifloxacin, ofloxacin, ciprofloxacin) for cases with copious purulent discharge, pain, marked inflammation, or suspected resistant organisms 1
• Contact lens wearers: Use fluoroquinolones due to higher risk of Pseudomonas infection 1

Special High-Risk Situations Requiring Systemic Antibiotics

Gonococcal Conjunctivitis 4, 1:

• Presentation: Marked eyelid edema, severe hyperpurulent discharge, preauricular lymphadenopathy, rapid onset 4
• Critical: Topical antibiotics alone are INSUFFICIENT—systemic therapy is mandatory 1
• Add saline lavage for comfort and faster resolution 1
• Complications: Can cause corneal perforation, septicemia, arthritis 4

Chlamydial Conjunctivitis 4, 1:

• Presentation: Follicular conjunctivitis, chemosis, distinctive follicles on bulbar conjunctiva and semilunar fold 4
• Critical: Requires systemic antibiotics; topical therapy provides no additional benefit 1
• Associated conditions: Cervicitis, urethritis, salpingitis, endometritis 4

Follow-Up and Red Flags

When to Reassess

• Return if no improvement after 3-4 days of treatment 1
• Perform visual acuity and slit-lamp examination at follow-up 1

Immediate Ophthalmology Referral Required 1, 2:

• Visual loss
• Moderate or severe pain
• Severe purulent discharge
• Corneal involvement
• Conjunctival scarring
• Lack of response to therapy
• Recurrent episodes
• Recent ocular surgery
• Vesicular rash on eyelids or nose
• History of rheumatologic disease
• Immunocompromised state

Critical Pitfalls to Avoid

• Never prescribe topical corticosteroids indiscriminately—viral conjunctivitis will not respond to antibacterials, and steroids can worsen viral infections 4
• Avoid local anesthetics—these should not be prescribed in primary care 7
• MRSA infections may require vancomycin if standard antibiotics fail 1
• Poor adherence to frequent dosing regimens contributes to treatment failure 1
• Consider sexual abuse in children with gonococcal or chlamydial conjunctivitis 1

Infection Control Measures

Educate patients on strict hygiene to break transmission chain 4:

• Wash hands frequently with soap and water (not sanitizer alone)
• Use separate towels and pillows
• Avoid close contact during contagious period
• Disinfect surfaces with EPA-registered hospital disinfectant 4
• Dilute bleach (1:10 sodium hypochlorite) for tonometer disinfection 4