Allergic rhinitis and inflammatory airway disease: interactions within the unified airspace.
BACKGROUND
Allergic rhinitis (AR), the most common chronic allergic condition in outpatient medicine, is associated with immense health care costs and socioeconomic consequences. AR's impact may be partly from interacting of respiratory conditions via allergic inflammation. This study was designed to review potential interactive mechanisms of AR and associated conditions and consider the relevance of a bidirectional "unified airway" respiratory inflammation model on diagnosis and treatment of inflammatory airway disease.


METHODS
MEDLINE was searched for pathophysiology and pathophysiological and epidemiologic links between AR and diseases of the sinuses, lungs, middle ear, and nasopharynx.


RESULTS
Allergic-related inflammatory responses or neural and systemic processes fostering inflammatory changes distant from initial allergen provocation may link AR and comorbidities. Treating AR may benefit associated respiratory tract comorbidities. Besides improving AR outcomes, treatment inhibiting eosinophil recruitment and migration, normalizing cytokine profiles, and reducing asthma-associated health care use in atopic subjects would likely ameliorate other upper airway diseases such as acute rhinosinusitis, chronic rhinosinusitis (CRS) with nasal polyposis (NP), adenoidal hypertrophy, and otitis media with effusion.


CONCLUSIONS
Epidemiological concordance of AR with several airway diseases conforms to a bidirectional "unified airway" respiratory inflammation model based on anatomic and histological upper and lower airway connections. Epidemiology and current understanding of inflammatory, humoral, and neural processes make links between AR and disorders including asthma, otitis media, NP, and CRS plausible. Combining AR with associated conditions increases disease burden; worsened associated illness may accompany worsened AR. AR pharmacotherapies include antihistamines, leukotriene antagonists, intranasal corticosteroids, and immunotherapy; treatments attenuating proinflammatory responses may also benefit associated conditions.
Marple
Bradley F
BF
Department of Otolaryngology-Head and Neck Surgery, UT Southwestern Medical Center at Dallas, Dallas, Texas 75390-9035, USA. Bradley.Marple@UTSoutwestern.edu
D000305:Adrenal Cortex Hormones / Q000627:therapeutic use; D000893:Anti-Inflammatory Agents / Q000627:therapeutic use; D001249:Asthma / Q000188:drug therapy / Q000453:epidemiology* / Q000276:immunology*; D001980:Bronchi / Q000187:drug effects / Q000276:immunology; D002450:Cell Communication; D002986:Clinical Trials as Topic; D015897:Comorbidity; D006801:Humans; D007249:Inflammation; D010256:Paranasal Sinuses / Q000187:drug effects / Q000276:immunology; D015995:Prevalence; D012137:Respiratory System / Q000187:drug effects / Q000276:immunology* / Q000378:metabolism / Q000473:pathology; D012221:Rhinitis, Allergic, Perennial / Q000188:drug therapy / Q000453:epidemiology* / Q000276:immunology*; D006255:Rhinitis, Allergic, Seasonal / Q000175:diagnosis / Q000188:drug therapy / Q000453:epidemiology* / Q000276:immunology*; D012307:Risk Factors
D000305:Adrenal Cortex Hormones; D000893:Anti-Inflammatory Agents