Allergic rhinitis pathophysiology

Adapted from American Academy of Allergy.3 (From May JR, Smith PH. Allergic Rhinitis. In DiPiro JT, Talbert RL, Yee GC, et al, (eds.) Pharmacotherapy A Pathophysiologic Approach. 6th ed. New York McGraw-Hill 2005 1734, with permission.)... 

Furthermore, the immunologic pathway involved in the pathophysiology of AD is complex (table 2). It presents a degree of complexity which has not been appreciated with allergic rhinitis and asthma. In AD both Thl and Th2 T cell products play a role in chronic inflammation, which is maintained by both IL-5 (Th2) and IFN-y (Thl) [51]. In addition recent studies have demonstrated different cytokine expressions in acute (predominantly IL-16) and in chronic (mainly IL-12 and GM-CSF) lesions [52, 53]. 

Skoner DP. Allergic rhinitis Definition, epidemiology, pathophysiology, detection, and diagnosis. J Allergy Clin Immunol 2001 8 S2-S8. 

Today a vast number of medications are available or under study for the treatment of allergic rhinitis. This chapter will focus on the pathophysiology of allergic rhinitis and the pharmacological rationale behind current and emerging therapies. 

Naclerio RM. Pathophysiology of perennial allergic rhinitis. Allergy 1997 52(suppl 36) 7-13. 

Segura T, Casale T. Allergic rhinitis basic pathophysiology and therapeutic strategies. Can J Allergy Clin Immunol. 1999 4(7) 318-330. 

Histamine is formed from the amino acid histidine and is stored in high concentrations in vesicles in mast cells. Histamine is metabolized by the enzymes monoamine oxidase and diamine oxidase. Excess production of histamine in the body (by. for example, systemic mastocytosis) can be detected by measurement of imidazoleacetic acid (its major metabolite) in tbe urine. Because it is released from mast cells in response to IgE-mediated (immediate) allergic reactions, this autacoid plays an important pathophysiologic role in seasonal rhinitis (hay fever), urticaria, and angioneurotic e ma. Histamine also plays an important physiologic role in the control of acid secretion in the stomach and as a neurotransmitter. 

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