A review on allergic conjunctivitis, pathophysiology, conventional and new emerging techniques for treatment

Abstract

Allergic conjunctivitis is a common ocular condition characterized by inflammation of the conjunctiva in response to allergens and sub conjunctivitis hemorrhage. Allergic conjunctivitis is primarily mediated by immunoglobulin E (IgE)-mediated hypersensitivity reactions. Exposure to allergens, such as pollen, dust mites, or pet dander, triggers the release of histamine and other inflammatory mediators from mast cells and eosinophils. These mediators, including histamine, leukotrienes, and prostaglandins, result in conjunctival vasodilation, increased vascular permeability, and activation of inflammatory cells, leading to redness, itching, and tearing. Chronic exposure to allergens can cause chronic allergic conjunctivitis and lead to complications like papillary conjunctivitis. Anti-histamines: Topical antihistamine eye drops (e.g., olopatadine, ketotifen) help relieve itching and redness by blocking histamine receptors. Mast Cell Stabilizers: Cromolyn sodium eye drops prevent mast cell degranulation. Decongestants: Eye drops with vasoconstrictors like naphazoline provide temporary relief from redness. Corticosteroids: These are reserved for severe cases due to the risk of side effects. Immunotherapy: Sublingual or subcutaneous immunotherapy (SLIT or SCIT) can help desensitize the immune system to specific allergens, reducing allergic reactions over time. Biologic Therapies: Monoclonal antibodies like omalizumab and dupilumab have shown promise in the treatment of severe allergic conjunctivitis by targeting specific pathways involved in allergic inflammation. Nasal-to-Ocular Delivery: Innovative drug delivery methods aim to provide targeted therapy to the eyes via nasal-to-ocular routes, improving drug efficacy while minimizing systemic side effects. Gene Therapy: Ongoing research explores gene therapy approaches to modify the immune response, potentially offering a long-term solution for allergic conjunctivitis. Conventional treatments focus on symptom relief, while emerging techniques, such as immunotherapy, biologic therapies, novel drug delivery methods, and gene therapy, hold promise for addressing the underlying immune response and providing more targeted and long-lasting relief for individuals suffering from allergic conjunctivitis. Further research and clinical trials are essential to validate the safety and efficacy of these emerging treatments and enhance the management of this prevalent ocular condition.