Introduction: Persulfate salts have been identified as a cause of occupational asthma (OA) in hairdressing professionals. The objective of this study is to describe the clinical and inflammatory characteristics before and after the specific inhalation challenge (SIC) in individuals suspected of OA to persulfate salts.

Material and methods: Retrospective study that included 82 patients with suspected OA to persulfate salts in whom SIC was performed. Data were collected from the clinical history, exposure, and complementary examinations performed before and after the SIC: pulmonary function test, methacholine test, and exhaled breath condensate analysis (EBC).

Results:In 27 patients SIC was positive (OA Group) and in 55, SIC was negative (Non-OA Group) (Table 1). No significant differences were found in terms of sex, age, smoking habit, or eosinophilia, between both groups. An increase in specific IgE levels was observed in the AO Group compared to the non-AO Group (p=0.013). In the OA group, there is a trend towards a longer duration of symptoms before diagnosis (p=0.07) together with a decrease in the pH in the EBC (p=0.079). A significant decrease in methacholine pc20 was observed after SIC in the AO Group (p=0.005).

Conclusion: The EBC pH analysis and the methacholine test together with the SIC are useful tools for the diagnosis of OA. The significant increase in IgE in those with SIC supports the existence of an IgE-dependent mechanism involved in the pathogenesis of OA due to persulfate exposure.