User:Saltrabook/Diagnostic Guidelines/Introduction

Asthma is ‘occupational’ when it has been caused directly by an agent encountered at work – usually an airborne allergen. Repeated inhalation causes a respiratory hypersensitivity in some people, which is similar to ordinary allergic asthma in response to house dust mites or cats. Risky jobs Around 400 workplace agents have been reported to cause occupational asthma. Fortunately, most of these are rarely encountered and about three-quarters of all the cases in the UK are attributable to only a handful of exposures (see box, below).