Evidence from:
DJ Hendrick. Clinical and Experimental Allergy Vol. 31 Jan (2001) p.1.
An editorial on occupational asthma.
The author notes that 11% of incident cases of occupational asthma are in fact reactive airways dysfunction syndrome I.e. no allergen involved. Triggered by irritants and viruses.
Comment
An important distinction, and one which is increasingly suspected for childhood asthma.