Accurate regulatory classification of chemical respiratory allergens: the case for robust characterisation of causation
This latest paper by Pemberton and Kimber recognizes the importance of accurate characterisation of occupational asthma and the discrimination between allergic asthma, irritant-induced asthma, and work-exacerbated asthma, to effective health management, sound chemical regulation and future research. The authors point out that since there are currently no available experimental method to accurately identify chemical respiratory allergens, that medical diagnosis of occupational asthma is dependent on specialist interpretation of clinical and workplace histories, and specific inhalation challenge tests conforming to current guidelines and best practice. Using selected clinical case studies, the authors go on to highlight key issues with the way that this clinical evidence is collected that confound the attribution of causation and the possible mechanisms involved. These clinical case studies were selected from classification reviews performed by the EU Committee for Risk Assessment (RAC) and inevitably focused on methyl methacrylate (MMA) (position statement link) and support the conclusion previously drawn by the same authors that MMA is a irritant substance and not a respiratory sensitiser, or a cause of occupational asthma (Methyl methacrylate and respiratory sensitisation: a comprehensive review).