TOPLINE:

A few exhaled volatile organic compounds — specifically decane and nonadecane — showed potential to identify allergic patients among those with chronic rhinitis, with 76.5% sensitivity and 69.2% specificity.

METHODOLOGY:

• Researchers analyzed 102 adults with perennial rhinitis (mean age, 38.05 years; 65.7% female) to assess the ability of five exhaled volatile organic compounds (decane, nonadecane, acetone, styrene, and nonanal) to differentiate patients with allergic rhinitis from those with nonallergic rhinitis.
• Participants were stratified into allergic rhinitis (n = 28), local allergic rhinitis (n = 31), and nonallergic rhinitis (n = 29) groups. Healthy control individuals (n = 14) were also included in the analysis.
• A nasal challenge with multiple allergens was performed for diagnostic classification, followed by a nasal challenge with a single allergen to assess the effect of exposure to the allergen on exhaled biomarker levels.
• Exhaled breath samples were collected immediately before and 24 hours after the nasal challenge and analyzed.
• Patient data were randomly divided into training (n = 72) and validation (n = 30) sets to build and test predictive models to discriminate patients with allergic rhinitis from those with nonallergic rhinitis and control individuals.

TAKEAWAY:

• In the validation set, a model based on decane and nonadecane achieved an area under the receiver operating characteristic curve (AUC) of 0.760 (95% CI, 0.585-0.935), with 76.5% sensitivity and 69.2% specificity.
• In another model, the same two compounds moderately differentiated participants with local allergic rhinitis from those with nonallergic rhinitis, with an AUC of 0.737 (95% CI, 0.545-0.929).
• Significantly higher levels of decane were observed in the local allergic rhinitis group than in control individuals (P = .007), and significantly higher levels of nonadecane were found in the local allergic rhinitis group than in the nonallergic rhinitis group (P = .026).
• At baseline, participants with fractional exhaled nitric oxide ≥ 25 ppb had higher median levels of all five volatile organic compounds, with significant associations for decane, styrene, and nonanal (P < .05 for all).

IN PRACTICE:

“VOCs [volatile organic compounds] should not be used as a standalone diagnostic tool, as they cannot identify the culprit allergen. Conversely, integrating VOCs with multi-omic approaches, established biomarkers, and clinical risk factors may help select suitable candidates for confirmatory tests such as NAC [nasal allergen challenge] or BAT [basophil activation test],” the authors of the study wrote.

SOURCE:

Teresa De Diego Puente, University of Murcia, Murcia, and Almudena Testera-Montes, Hospital Regional Universitario De Malaga, Malaga, Spain, were the corresponding authors of the study, which was published online on February 27, 2026, in Allergy.

LIMITATIONS:

The study was limited by its small sample size and a relatively small validation set. It focused on monosensitized patients with perennial rhinitis, which limited generalizability. Allergen-induced changes were assessed at a single 24-hour timepoint, so earlier or transient changes may have been missed. Finally, some environmental exposures, particularly outdoor air pollution, were not fully quantified.

DISCLOSURES:

The study was supported by Instituto de Salud Carlos III and the Regional Ministry of Health of Andalusia and by contracts and fellowships from various organizations and institutions including Horizon Europe and the University of Murcia. Several authors reported receiving honoraria for lectures and advisory activities from various companies including GSK, AstraZeneca, Sanofi, and Novartis.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.