Abstract
Introduction: Quaternary ammonium compounds (QACs) are used as detergents or disinfectants and known to induce occupational asthma. Moreover, clinical reports with bronchial challenge tests (BCTs) that demonstrated the role of QACs are rare.
Objectives: To analyse the clinical response obtained during a positive BCT in 16 patients with occupational asthma to QACs.
Methods: A realistic BCT was performed in an experimental chamber with didecyl dimethyl ammonium chloride (DDAC) at 0.1%. This concentration corresponded to the lowest concentration of DDAC to which patients were exposed at workplace. A positive BCT was defined as a 20% drop in FEV1 or a change of 2 doubling dose in non-specific BCT to methacholine.
Results: 14 women and 2 men (mean age = 47.8 y.) were included from 2008 to 2011. 11 of them (62.5%) were healthcare workers: 1 dentist, 1 dentist-assistant, 2 nurses, 5 auxiliary nurses, 1 janitor. 5 of them (37.5%) were cleaners. 69% had also occupational rhinitis and 19% occupational contact dermatitis to QACs. The mean duration of exposure during BCT was 28 minutes [3-60]. Same BCTs were negative in 6 control patients with work-related asthma due to another cause and exposed to QACs.
Conclusions: Our study demonstrated the usefulness of BCT to confirm an occupational asthma to QACs. As compared to previous publication from our group, bronchial response occurred more rapidly suggesting a sensitisation to DDAC.
- © 2012 ERS