Biological Characteristics and Role of Histamine in Case of Allergic Rhinitis

Histamine exerts its biological effect an humans through interaction with four histamine receptors (H1R, H2R, H3R and H4R). Histamine is a major mediator of allergic rhinitis (AR) that produces classical symptoms (sneezing, itching, rhinorrhea and congestion) both in adults and children. Nasal itch, sneezes, and rhinorrhoea are predominantly neural, while congestion is predominantly vascular. Antagonism of H1 receptors reduces majority of AR symptoms, which act primarily by the reversible and competitive inhibition of histamine action at H1R. To date, antihistamines are among the most commonly used pharmacological treatments in AR. This paper reviews the characteristic of histamine and histamine receptors in humans and the implication of antihistamine on AR.