A gap in surface therapy: topical antihistamines.
Allergic and non-allergic rhinitis have been treated by many drugs with different modes of action such as topical disodium cromoglycate and ipratropium bromide, systemic antihistamines and corticosteroid drugs and topical corticosteroids. Yet, these therapies are not entirely satisfactory for all symptoms. The rationale for the topical, intranasal use of antihistamines in patients is discussed. Topical antihistamine agents are administered in order to avoid the side effects of systematically applied medications, and to reach higher local drug concentrations. H1 receptors of the nasal mucosa play an important role in the physiopathology of allergic and non-allergic rhinitis and even of infectious rhinitis. Most studies using topical antihistamines in rhinitis, had an experimental physiopathological aim and did not explore clinical efficacy. Recently, topical application of levocabastine--a potent H1 antagonist--yielded good clinical results in allergic conjunctivitis, seasonal allergic rhinoconjunctivitis, and non allergic perennial rhinitis.