Protective effect of loratadine on specific conjunctival provocation test

Area of Science:

• Ophthalmology
• Allergology
• Immunology

Background:

• Seasonal allergic rhinoconjunctivitis is a common condition causing significant ocular discomfort.
• The early phase of allergic conjunctival reactions involves rapid inflammatory responses.
• Understanding the efficacy of antihistamines in managing these early reactions is crucial.

Purpose of the Study:

• To evaluate the protective effect of loratadine, an H1 antagonist, on early clinical and cellular responses in allergic conjunctivitis.
• To assess loratadine's impact on allergen threshold and symptom severity following conjunctival provocation.

Main Methods:

• A double-blind, randomized, placebo-controlled study involving 20 patients with seasonal allergic rhinoconjunctivitis.
• Patients received a daily dose of loratadine 10 mg or placebo for 7 days.
• Conjunctival provocation tests were performed to assess allergen threshold, symptom severity, and inflammatory cell counts.

Main Results:

• Loratadine pretreatment significantly increased the allergen threshold dose compared to placebo (p < 0.01).
• Patients receiving loratadine showed a significant reduction in conjunctival symptom severity (p < 0.01).
• A significant decrease in inflammatory cell counts was observed in the loratadine group (p < 0.01).

Conclusions:

• Loratadine demonstrates significant protective effects against early-phase allergic conjunctival reactions.
• The findings support loratadine's efficacy in mitigating both clinical symptoms and cellular inflammatory events in allergic rhinoconjunctivitis.