Inhalation challenge test in the diagnosis of occupational rhinitis

Evaluations of rhinitis reactions in inhalation challenges (ICs) are sparse compared with research on nasal challenges. This study evaluates the outcome of IC tests in assessing occupational rhinitis (OR). It presents the largest rhinologic IC data in the literature, analyzing the exposure method of various agents causing OR and their relation to asthma.

Challenge tests performed on 829 individuals with suspected cases of OR were reviewed. Results from both exposures with occupational agents (n = 1229) and placebo (n = 838) were evaluated.

A total of 10% of the occupational ICs (n = 123) were positive, suggesting OR, and 13% (n = 161) showed asthmatic reaction in the same challenge. In control challenges 2% showed rhinitis and 6% showed asthma symptoms. The most common agents tested were molds (160 tests), flours, and animal fodders (115 tests) and formaldehyde (122 tests). Obeche wood dust and latex produced positive nasal reactions the most frequently, followed by acid anhydrides.

Although IC is a resource-intensive methodology, the evaluation of nasal symptoms and signs together with bronchial reactions saves time and expense compared with the organization of multiple individual challenges. We encourage the simultaneous evaluation of both nasal and bronchial reactions in IC tests.