 Allergic rhinitis is a nasal inflammatory disorder initiated by an immunoglobulin-E IgE mediated hypersensitivity to allergens. This condition is characterized by sneezing, rhinorrhea, nasal itching and congestion. When a patient is exposed to an allergen to which they are sensitive, the allergen cross-links with the Ig E antibody, which is bound to the surface of tissue mast cells. This cross-linking then triggers the release of proinflammatory substances, such as histamine and eicosanoids, and is known as the early response. In a skin prick test, this reaction produces a wheal-and-flare response. Normally, systemic exposure to an allergen also leads to the more prolonged late reaction, in which eosinophils, basophils, and activated T cells are recruited to the site of exposure. The recruited T cells also secrete inflammatory cytokines, such as interleukin-4 IL-4 and IL-5, typically associated with helper T cells type 2 TH2, which further propagate the inflammatory cascade. Typically, the early response occurs within 15 to 30 minutes but as quickly as a few seconds and usually resolves within 1 to 3 hours, and the late response occurs within 6 to 12 hours and resolves in 24 hours. 