Test to confirm occupational asthma

I am hoping you could help me with a patient with occupational asthma. I have a patient who has informed me that he was exposed to propanol 2 and has developed asthma. Propranol 2 is a isopropyl alcohol, which is used in hair sprays etc so it could cause occupational asthma. The question is 'Is there a test that could be used to confirm it', as it is going to have legal implications

Occupational Asthma, Specialist, 2/20/2006, 2/20/2006,

Specific challenge testing is the best way to confirm that a specific low-molecular weight agent is the cause of asthma. Serial measurements of peak expiratory flow will show that occupational asthma exists, but will not define the cause. Serial PEF measurements should be done first if your worker is still exposed, as failure to show any changes related to exposure makes the interpretation of any subsequent specific challenge problematical. If your patient is a hairdresser, there are several other agents that might cause occupational asthma, particularly persulphates and occasionally henna.

2/20/2006