What are the recommended eye drops for a patient with allergic conjunctivitis?

Eye Drops for Allergic Conjunctivitis

Dual-action agents combining antihistamine and mast cell stabilizer properties—specifically olopatadine, ketotifen, epinastine, or azelastine—are the recommended first-line eye drops for allergic conjunctivitis due to their rapid onset (within 30 minutes) and ability to both treat acute symptoms and prevent future episodes. 1, 2

First-Line Pharmacological Treatment

• Start with dual-action topical agents as they provide superior efficacy compared to single-mechanism drugs 1, 2
• Olopatadine 0.1%: 1 drop in affected eye(s) twice daily, every 6-8 hours (FDA-approved for ages 2 years and older) 3
• Ketotifen: 1 drop in affected eye(s) twice daily, every 8-12 hours (FDA-approved for ages 3 years and older) 4
• These agents work within 30 minutes and maintain efficacy for 8-12 hours, making them suitable for both acute relief and chronic prophylactic use 2

Store eye drops in the refrigerator for additional cooling relief upon instillation, which provides symptomatic benefit 5, 1

Adjunctive Non-Pharmacological Measures

• Apply cold compresses for immediate symptomatic relief 5, 1
• Use refrigerated preservative-free artificial tears 4 times daily to dilute allergens and inflammatory mediators on the ocular surface 5, 1
• Wear sunglasses as a physical barrier against airborne allergens 5, 1
• Implement hypoallergenic bedding, eyelid cleansers to remove allergens, frequent clothes washing, and shower before bedtime 5, 1
• Counsel patients to avoid eye rubbing, as this can worsen symptoms and potentially lead to keratoconus, especially in atopic patients 5, 1

Second-Line Options for Prophylaxis

If dual-action agents are unavailable or symptoms require additional prophylaxis:

• Mast cell stabilizers alone (cromolyn, lodoxamide, nedocromil, pemirolast) are better for prophylactic or longer-term treatment but have slower onset of action (several days) 1, 2
• Topical NSAIDs such as ketorolac provide temporary relief of ocular itching but have slower onset than dual-action agents 1, 2

Escalation for Inadequate Response

If symptoms persist despite 48 hours of dual-action drops:

• Add a brief 1-2 week course only of loteprednol etabonate (low side-effect profile topical corticosteroid) 5, 1, 6
• Critical monitoring requirements: Obtain baseline intraocular pressure (IOP) measurement and perform pupillary dilation to evaluate for glaucoma and cataract formation 5, 1
• Continue periodic IOP monitoring throughout corticosteroid use 5, 1
• Never exceed 2 weeks of topical corticosteroid use due to risks of elevated IOP, cataract formation, and secondary infections 1, 2, 6

Severe or Refractory Cases

For cases unresponsive to the above treatments:

• Consider topical cyclosporine 0.05% (at least 4 times daily) or tacrolimus for severe allergic conjunctivitis 5, 1
• These agents are particularly useful for vernal keratoconjunctivitis or atopic conjunctivitis and may allow for reduced corticosteroid use 5, 1
• Refer to ophthalmology for severe cases requiring immunomodulatory therapy 1

Critical Pitfalls to Avoid

• Avoid chronic use of over-the-counter antihistamine/vasoconstrictor combinations (e.g., naphazoline/pheniramine), as prolonged vasoconstrictor use causes rebound vasodilation (conjunctivitis medicamentosa) once stopped 5, 1
• Avoid oral antihistamines as primary treatment because they may worsen dry eye syndrome and impair the tear film's protective barrier 5, 1, 2
• Never use punctal plugs in allergic conjunctivitis as they prevent flushing of allergens and inflammatory mediators from the ocular surface 1
• Avoid indiscriminate use of topical antibiotics as they provide no benefit for allergic disease, induce toxicity, and contribute to antibiotic resistance 5, 7

Pediatric Considerations

• Sodium cromoglycate (mast cell stabilizer) is the safest option for very young children with no age restriction, dosed 4 times daily 1
• Olopatadine is approved for children 2 years and older 3
• Ketotifen is approved for children 3 years and older 4

Duration of Treatment

• Seasonal allergic conjunctivitis: Use dual-action agents throughout the allergen exposure season, then discontinue when symptoms resolve 1
• Perennial allergic conjunctivitis: Continue dual-action agents as long as allergen exposure persists, with reassessment at regular follow-up visits 1
• Unlike vasoconstrictors or corticosteroids, dual-action agents have no specified maximum treatment duration and can be used long-term safely 2