Wednesday 26 November, 2025      |     Read Time: 5 mins

‍Beth Wright

‍

‍

We breathe more than 17,000 times a day - but what if your nose could reveal what’s happening deep in your lungs? [1]

The “unified airway” concept is transforming how we think about respiratory health.

It challenges the traditional view that our respiratory system is disconnected, with each organ acting separately, instead, we are now seeing that the entire airway - from nose to lungs - operates as one continuous system [2,3].This vital shift reflects a broader movement in medicine: viewing the body not as isolated parts, but as an interconnected whole [4].

This ‘whole picture’ view of the human body is the greatest tool we have at our disposal for tackling humanity’s greatest health threats - from asthma to cancer - and everything in between.

Your organs rarely act in isolation; even breathing is a group effort. What, then, is the Unified Airway?

The unified airway theory proposes that what happens in the nose provides powerful information about what might be happening in the lungs [5, 6].

This is already being made abundantly clear with patterns of biomarkers found in nasal fluid - such as certain proteins, cytokines, or gene expression signatures - mirroring lung function and even signalling early signs of disease. This is because the nose, sinuses, trachea, and lungs are made up of inherently connected cells and defended by similar immune pathways, meaning inflammation or dysfunction in one part will often affect the others.

For instance, think of your airway as a tree.

The trunk (trachea) and branches (nasal and lung passages) are connected. If one branch is diseased or inflamed, there is potential for disease to spread, and the impact may be felt by the rest of the tree. To make up for the lost source of energy from the leaves of one diseased branch, all across the tree small green shoots may sprout up to replace the lost leaf area.

This pattern is constantly reflected in our very own respiratory system.

The loss of tiny air sacs in the lungs - called alveoli - due to smoking or respiratory disease often shows up as persistent coughing or shortness of breath. Even in popular culture, coughing is commonly used as a symbol of illness or even impending death - how many movies have you seen that uses this trope? And although these signs may be obvious, think of how many other warning signals your body will send to you that may not be as clear to the eye.

‍

Behind the scenes of your respiratory system’s interconnection

‍Both upper and lower airways share common epithelial and immune characteristics, including mucus production, cilia movement, and cytokine-driven inflammation [7].

This biological overlap explains why nasal inflammation can trigger lower airway symptoms, and vice versa.

In a study comparing people with asthma to those without, researchers found that the tissue layer just beneath the surface of the airways, called the lamina reticularis, was thicker in both the nose and the lungs [8]. This thickening occurred not only in people with asthma and year-round allergies but also to some extent in healthy individuals.

Intriguingly, the amount of thickening in the nose closely matched the thickening in the lungs - strongly supporting that changes in one part of the airway often reflect what’s happening in another.

This insight is helping researchers and clinicians develop less invasive tests, such as nasal swabs, to monitor lung diseases - offering a simple, non-invasive window into respiratory health.

‍

Moving from isolated organs to integrated systems

‍For decades, modern medicine has treated organs as separate entities: lungs for pulmonologists, sinuses for ENT specialists, and allergies for immunologists.

The unified airway concept fits into the broader shift toward systems medicine - an approach that studies how different body systems interact to influence health and disease. The body doesn’t work in compartments, and collaboration across disciplines improves health outcomes.

This integrated approach enables earlier diagnosis, targeted treatment, and a lower healthcare burden by addressing root causes rather than isolated symptoms.

‍

Unifying asthma - the nose-lung Connection

‍Asthma research is one of the most powerful examples of the unified airway in action.Many people with asthma also experience nasal allergies, sinus inflammation, or hay fever. These aren’t separate issues - they’re connected through shared inflammatory pathways.When the upper airway is inflamed, it can worsen asthma control, increase medication use, and raise the risk of flare-ups [9].

Towards personalised, predictive asthma care

Studies show that treating allergic rhinitis or sinusitis often improves asthma symptoms and reduces the need for inhalers [10]. This demonstrates the sheer interconnectivity of our airway - and the importance of treating it as one system rather than in isolation to gain a more complete picture of each patient’s condition.‍

‍

Can your nose Diag-Nose?

‍It might sound futuristic, but research shows your nose could help diagnose diseases in the lungs. Recent studies reveal that molecular changes in nasal tissue - such as gene expression or methylation patterns - can reflect those in the lungs during the early stages of diseases like lung cancer [11]. This means a simple nasal swab could one day serve as a non-invasive screening tool for detecting lung cancer early, when treatment is most effective.

Beyond cancer, similar approaches are being explored for monitoring COPD [12], viral infections, and pollution exposure, potentially allowing for at-home testing and real-time disease tracking.

‍

What the unified airway means for the future of medicine

‍The unified airway concept represents more than a scientific theory - it’s a blueprint for the evolution of modern healthcare.

By treating the airway as one system, clinicians can move toward preventive, personalised, and precision-based care. Nasal swabs could soon help monitor asthma control, track treatment response, or detect cancer even before symptoms appear. Ultimately reducing the burden on patients and healthcare systems alike - improving outcomes, saving lives, and transforming how we view the human body.

‍What’s Next?

‍The next time you take a deep breath, remember - your nose and lungs are part of the same story, speaking the same biological language.

The unified airway concept reminds us that the body is not a collection of isolated parts, but a finely tuned, interconnected system.

By recognising and harnessing these connections, we can detect disease earlier, treat it more precisely, and move closer to truly personalised care.As science continues to listen to the signals our airways share, the future of respiratory health looks clearer, earlier, and more connected than ever before.‍‍‍

‍

‍

‍

References

1. Pleil, J. D., Ariel Geer Wallace, M., Davis, M. D., & Matty, C. M. (2021). The physics of human breathing: flow, timing, volume, and pressure parameters for normal, on-demand, and ventilator respiration. Journal of breath research, 15(4), 10.1088/1752-7163/ac2589. https://doi.[org/10.1088/1752-7163/ac2589

2. Braunstahl G. J. (2007). The united airways concept: from bench to bedside. Monaldi archives for chest disease, 67(2), 95–101. https://doi.[org/10.4081/monaldi.2007.496

3. Braunstahl G. J. (2009). United airways concept: what does it teach us about systemic inflammation in airways disease? Proceedings of the American Thoracic Society, 6(8), 652–654. https://doi.[org/10.1513/pats.200906-052DP

4. Grossman J. (1997). One Airway, One Disease. Chest, 111(2);11S-16S. doi: 10.1378/chest.111.2_Supplement.11S

5. Klain, A., Indolfi, C., Dinardo, G., Licari, A., Cardinale, F., Caffarelli, C., Manti, S., Ricci, G., Pingitore, G., Tosca, M., Decimo, F., & Miraglia Del Giudice, M. (2021). United airway disease. Acta bio-medica : Atenei Parmensis, 92(S7), e2021526. https://doi.[org/10.23750/abm.v92iS7.12399

6. Bousquet, J. et al. (2025), From “one airway, one disease” to “one airway, many diseases”, Journal of Allergy and Clinical Immunology, 156(1); 198 - 199, doi: 10.1016/j.jaci.2025.03.022

7.Braunstahl, G. J., Fokkens, W. J., Overbeek, S. E., KleinJan, A., Hoogsteden, H. C., & Prins, J. B. (2003). Mucosal and systemic inflammatory changes in allergic rhinitis and asthma: a comparison between upper and lower airways. Clinical and experimental allergy : journal of the British Society for Allergy and Clinical Immunology, 33(5), 579–587. https://doi.org/10.1046/j.1365-2222.2003.01652.x

‍8. Chanez P, Vignola AM, Vic P, et al. Comparison between nasal and bronchial inflammation in asthmatic and control subjects. Am J Respir Crit Care Med. 1999;159:588–95. doi: 10.1164/ajrccm.159.2.98010228.

9. Chang-Gyu Jung, Kathleen M. Buchheit, Grazyna Bochenek, Emily Dzoba, Seong Ho Cho,Upper airway comorbidities of asthma, Journal of Allergy and Clinical Immunology. 2024:154(6);1343-1354. https://doi.org/10.1016/j.jaci.2024.10.007.9.

10. Tameeris, E., Bohnen, A. M., Bindels, P. J. E., & Elshout, G. (2025). The effect of allergic rhinitis treatment on asthma control: a systematic review. NPJ primary care respiratory medicine, 35(1), 4. https://doi.org/10.1038/s41533-024-00408-410.

11. Wu, S.,Jiang, R., Fedorowicz, G. et al. Analytical validation of the Percepta Nasal Swab classifier; an RNA next-generation sequencing assay for the assessment of lung cancer risk in pulmonary nodules. BMC Cancer 25, 577 (2025). https://doi.org/10.1186/s12885-025-13683-2

12. Qureshi N (2022) Looking for the Genes Related to Lung Cancer From Nasal Epithelial Cells by Network and Pathway Analysis. Front. Genet: Human and Medical Genomics; 13: https://doi.org/10.3389/fgene.2022.942864‍

13. Boudewijn, I. M.,et al. (2017). Nasal gene expression differentiates COPD from controls and overlaps bronchial gene expression. Respiratory research, 18(1), 213. https://doi.org/10.1186/s12931-017-0696-5

‍