Allergic Rhinitis: Pathogenesis and clinical findings 1. Allergy Sensitization -> Antigen Exposure -> APC (macrophages, HLA class II) process antigen into peptides -> APC present peptides to Helper T cells -> Helper T cells release Interleukins (IL-4 and IL-3) -> IL-4 and IL-3 stimulate B-cell transformation to lgE producing Plasma Cells -> lgE Abs coat mast cells within nasal mucosa and basophils in the plasma 2. Primary Reaction Phase -> (initiated within 5 minutes of antigen exposure and maximum effect by 15 minutes) Antigen Exposure -> Antigen binds to lgE on mast cells and basophils -> Mast cells & basophils release mediators: preformed (histamine, serotonin, protease) & newly-generated (leukotrienes, prostaglandins, TNF-a) 3. Secondary Reaction Phase (occurs 4-6 hours after the primary reaction phase) Presence of mediators -> Recruitment of inflammatory cells (neutrophils, eosinophils, macrophages, lymphocytes), bone marrow proliferation of eosinophils -> Second phase of mediators released • Rhinorrhea • Sneezing and itching • Congestion and pressure • Tissue edema #Allergic #Rhinitis #Rhinorrhea #pathophysiology
