Topical Corticosteroids and Antihistamines—Mast Cell Stabilizers for the Treatment of Allergic Conjunctivitis

The most common ocular manifestation of allergy, allergic conjunctivitis (AC), is the result of a hypersensitivity response occurring after exposure of the ocular surface to airborne antigens. Treatment options for AC comprise antihistamines, mast cell stabilizers, dual-acting mast cell stabilizer-antihistamines, corticosteroids, nonsteroidal anti-inflammatory drugs (NSAIDs), and combinations thereof. Despite clinical evidence to support the use of antihistamines, such as levocabastine, antihistamines are unable to mitigate all symptoms of AC because histamine is not the only mediator released during the allergic inflammatory response and has no direct effect on inflammatory cells involved in clinical symptoms. Dual-acting mast cell stabilizer-antihistamines, such as bepotastine, alcafatidine, epinastine, ketotifen, and olopatadine, have a broader effect than antihistamines alone. Corticosteroids inhibit the entire inflammatory cascade and therefore offer the most complete option for AC, although their use has been limited due to concerns about increased intraocular pressure (IOP) and the potential for cataract formation with extended use. Loteprednol etabonate (LE) has a decreased effect on IOP and cannot form Schiff base intermediates with lens protein, which is considered a first step in cataractogenesis. The efficacy and safety of LE in the treatment of seasonal AC (SAC) has been demonstrated in clinical trials.