SELECTED ARTICLES FROM THE RECENT LITERATURE 2005
9/13/05
Histamine receptors in the conjunctiva
Summary
Background - Conjunctival symptoms occur commonly in allergic reactions. Histamine is thought to be a major mediator involved in such conjunctival reactions.
Findings - Bielory and Ghafoor of the New Jersey Medical School in Newark, NJ reviewed the actions of histamine (H) on the conjunctiva. The primary effect of H is mediated through binding to H1 receptors leading to pruritus. H binding to the H2 receptors appears to work in a complementary manner to the binding to H1 receptors in controlling other features of ocular allergy such as vasodilatation and tearing. Thus, agents which antagonize H effects at both the H1 and H2 receptors should provide improved control of the various signs and symptoms of ocular allergy.
Reference
Curr Opin Allergy Clin Immunol 2005;5:437-440
Editor's Comments
These comments by very experienced observers of ocular allergy highlight the reasons why treatment with typical H1 antihistamines relieve some, but not all, the symptoms of ocular allergy. In my experience, treatment with oral antihistamines has a variable beneficial effect on ocular allergy manifestations. Topically applied potent H1 antihistamines may be more helpful, related to higher local concentrations of the H1 antihistamine. However, eye drops with more broad based H1 and H2 receptor antagonism may be even more effective.
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