Management of allergic conjunctivitis

Allergic conjunctivitis, unlike several other ocular diseases, is very seldom followed by permanent visual impairment; nevertheless its importance is due to both its frequency and its severity. A thorough knowledge of the pathophysiological aspects and clinical features of allergic conjunctivitis allows physicians to choose the best and most suitable management from the many alternatives. Management varies according to symptom severity and the characteristics of the allergic reaction, generally, it is based on environmental control, pharmacotherapy and, sometimes, specific immunotherapy. Topical vasoconstrictors, decongestant compounds or classic histamine H-1 antagonists, or combinations of these drugs, have been available for decades to treat the acute and/or persistent symptomatology, and to prevent the adverse effects of prolonged treatment with topical corticosteroids. Nevertheless, corticosteroids are the most powerful anti-inflammatory drugs, and are particularly recommended for the short term treatment of severe, acute symptomatology. Orally administered histamine H-1 receptor antagonists are effective and convenient for either short or long term treatment, especially since the newer second-generation compounds, such as cetirizine, loratadine and terfenadine, act also on the inflammatory process underlying the allergic event. Recently, other topical compounds such as sodium cromoglycate (cromolyn sodium), nedocromil, lodoxamide, spaglumic acid and nonsteroidal anti-inflammatory drugs have been available. Sodium cromoglycate, nedocromil, lodoxamide and spaglumic acid exert an antiallergic activity by stabilising the mast cell membrane; nonsteroidal antiinflammatory drugs represent an effective alternative to corticosteroids in some cases. The aim of this review is a global evaluation of the common and up-to-date pharmacologically available protocols in the treatment of allergic conjunctivitis.