Chemical Mediators Causing Symptoms of Allergic Rhinitis
Mediator Symptoms Produced
Histamine Stuffy nose, runny nose, sneezing, itchy nose,
itchy throat, itchy palate, itchy ears
Prostaglandin D2 Inflammation of nose
Leukotrienes Runny nose, stuffy nose, inflammation
Each of these mediators exerts its effect by interacting with a receptor on the surface of a specific cell in the nasal tissue. Histamine, for example, binds to one of two types of receptors, called H1 and H2 receptors. Tissue that doesn’t contain either of these receptors cannot be acted upon by histamine. It is mainly through the H1 receptor that histamine stimulates tissues in your nose and causes allergic symptoms. Antihistamines and other medications used to treat allergic symptoms act by blocking the receptors through which the chemical mediators work. Thus, antihistamines work mainly by blocking the interaction of histamine with the H1 receptor.