Allergic Rhinitis and Inflammatory Airway Disease: Interactions within the Unified Airspace

Abstract

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.

Comorbidities of asthma and the unified airway

“…[52][53][54] The eosinophil is drawn to the inflammatory reaction by the T helper 2 (TH2) cytokine interleukin 5 (IL-5). 55 IL-5 mediates eosinophil expansion, priming, recruitment, and prolonged tissue survival in allergic reactions.…”

Expression of Epidermal Growth Factors, erbBs, in the Nasal Mucosa of Patients with Chronic Hypertrophic Rhinitis

“…We further found that peripheral blood eosinophilia occurred in parallel with tissue eosinophilia and with the erbB1 expression in the nasal gland. The role of eosinophil activation in the pathogenesis of chronic nasal mucosal diseases has been reported in previous studies [19] . Burgel et al [15,20] have documented that activated eosinophils secrete cytokines such as transforming growth factor-␣ and tumor necrosis factor-␣ , which induce the expression of erbB1 on airway epithelial cells.…”

From Mouse to Man: Translational Value of Animal Models of Allergic Rhinitis

“…Although delivery to the nose is optimized with these approaches, subtle effects in the lung, either direct or indirect, cannot be completely discounted. As discussed in the introduction to this chapter, the "united airway" hypothesis linking AR to asthma suggests that immunogenic responses in upper and lower airways are connected (Marple 2010;Pawankar 2006). While asthma:rhinitis relationships are clearly evident in clinical and epidemiological studies, reports from animals models are limited and without a consensus mechanism.…”

“…Given the clinical and pathologic commonalities of AR and asthma, recent efforts of physicians worldwide has led to Allergic Rhinitis and its Impact on Asthma (ARIA), a collaborative development of diagnostic and therapeutic strategies to treat AR as an asthma risk (Bousquet et al 2001). A central tenet of ARIA is that AR and asthma represent a "united airway disease" and should be viewed as an interrelated disease with common etiology, features and treatments (Compalati et al 2010;Marple 2010). However the inherent differences in the anatomic, morphologic, and functional aspects of nasal versus pulmonary airways result in unique inflammatory and allergic responses in each site.…”