title: The pathophysiology, clinical impact, and management of nasal congestion in allergic rhinitis.
abstract: BACKGROUND
  Nasal congestion is a cardinal symptom of allergic rhinitis (AR). It is difficult to treat and is associated with decreased quality of life.
  
  
  OBJECTIVE
  This article reviews the clinical features of nasal congestion, its complex pathophysiology in the context of AR, its clinical impact, and the strengths and weaknesses of available treatments.
  
  
  METHODS
  Primary studies and reviews in the peer-reviewed, English-language literature were identified through searches of MEDLINE (1966-2008) and the Cochrane Library (1996-2008) using the terms nasal congestion, allergic rhinitis, pathophysiology, quality of life, and burden. Additional references were obtained by searching the reference lists of the identified articles. Abstracts from the 2006 and 2007 meetings of the American Academy of Allergy, Asthma, and Immunology were also searched. Pertinent articles were included in the review if they were recently published and patient-focused, and if their authors were recognized leaders in the field.
  
  
  RESULTS
  A survey of 2355 patients with AR or their guardians found that almost half of respondents rated nasal congestion the most bothersome symptom; in a survey of 2500 adults with AR, 78% rated nasal congestion either extremely or moderately bothersome. Histamine and leukotrienes are major mediators of the allergic inflammation associated with nasal congestion, as indicated by reductions in nasal cross-sectional area in response to histamine challenge (P<0.001) and increases in nasal airway resistance in response to leukotriene challenge (P<0.05).Therapy for nasal congestion in AR is often hampered by limitations associated with the individual agents; for example, decongestants are effective in the control of nasal congestion, but their use is restricted by their adverse-event profiles. A meta-analysis of 16 controlled studies involving 2267 patients with AR found that intranasal corticosteroids provided significantly greater relief of nasal congestion than oral antihistamines (95% CI for combined standardized mean difference, -0.73 to -0.53). The results of several clinical trials have suggested that leukotriene-receptor antagonists may be associated with reduced nasal congestion; however, no agents in this class are currently approved for the treatment of nasal congestion in AR.
  
  
  CONCLUSIONS
  There is a need for therapies that are well tolerated and effective in relieving nasal congestion in AR.
authors.affiliation: Department of Medicine, University of Colorado Health Sciences Center, Denver, Colorado, USA. DrRNathan@aol.com
authors.forename: Robert A
authors.initials: RA
authors.lastname: Nathan
mesh_terms: D005938:Glucocorticoids / Q000627:therapeutic use; D006632:Histamine / Q000378:metabolism*; D006634:Histamine H1 Antagonists / Q000627:therapeutic use; D006801:Humans; D015289:Leukotrienes / Q000378:metabolism*; D014663:Nasal Decongestants / Q000627:therapeutic use; D011379:Prognosis; D011788:Quality of Life; D012221:Rhinitis, Allergic, Perennial / Q000188:drug therapy / Q000209:etiology / Q000378:metabolism; D013566:Sympathomimetics / Q000627:therapeutic use
chemical_list: D005938:Glucocorticoids; D006634:Histamine H1 Antagonists; D015289:Leukotrienes; D014663:Nasal Decongestants; D013566:Sympathomimetics; D006632:Histamine