Occupational rhinitis in workers investigated for occupational asthma

Background: The links between asthma and rhinitis are nowadays referred to as the united airways disease (UAD). Current evidence shows that the UAD model seems to be applicable to occupational rhinitis (OR) and occupational asthma (OA). Objective: We aimed to objectively assess, in the context of specific inhalation challenge (SIC) testing, the concomitance of bronchial and nasal reaction in the investigation of OR and OA Methods: Forty-three subjects with a history of work-related asthma symptoms underwent SIC for confirmation of OA and investigation of OR. Subjects underwent assessment of changes in bronchial calibre by spirometry and assessment of nasal patency and airway inflammation by acoustic rhinometry and nasal lavage. Results: A positive nasal challenge was observed in 25 SIC whereas a positive bronchial challenge was observed in 17 SIC. A concomitant positive nasal and bronchial challenge was observed in 13 instances. This association was significant (risk ratio= 1.7; 95% CI=1.0 to 2.4; p=0.04) and more frequent in subjects challenged with high molecular weight (n= 11/22) than low-molecular weight agents (n= 2/21). Among subjects with a positive nasal challenge, nasal lavage showed a significant increase in eosinophils at 30 min post-exposure that correlated with changes in nasal patency. Conclusion: Results provided objective evidence supporting the UAD concept by using OR and OA as a model for demonstrating a concomitant significant physiological reaction of the nose and lungs after challenge. We demonstrated that OR can be assessed by objective means; this condition often coexists with OA but can be present without OA.