Work exacerbated asthma

I have a chap with 6 weeks of good PEFR monitoring from early 2005 whom I suspect has constitutional asthma well before coming into contact with hexamine in 2000. His symptoms worsened from 2002 and he was removed from the plant in 2005 after 6 weeks of pefr monitoring in and out of work. I was not convinced that his PEFR during chemical exposure were much different in and out of work although he did appear to have more diurnal variability on work days around 10% of predicted his oasys score was 2.41. I wonder if he has a dgree of worsening of asthma due to exposure rather than true OA. strong family Hx of asthma and had previously been investigated by PEFR in the 90's and again in 1998 with no confirmed diagnisis but always a low PEFR ~450 (Pred 540 at that time) and occasional improvement with ventolin. He also did 2 weeks of pefr at work but in a different part of the plant where he was not exposed to hexamine prior to the above monitoring. His oasys score was surprisingly 3.0 but he only had one day off so I assume this is a confounding factor? Anees W, Gannon PF, Huggins V, Pantin CFA, Burge PS, Effect of peak expiratory flow data quantity on diagnostic sensitivity and specificity in occupational asthma, Eur Respir J, 2004;23:730-734,

Occupational Asthma, Specialist, 10/12/2009, 10/12/2009,

Occupational asthma can occur in a worker with pre-existing asthma, some call this work-exacerbated asthma but the presence of a 2 year latent interval suggests additional sensitisation. Both need similar management, if usual work exposures are making the asthma worse relocation or reduced exposure is needed. If there is only 1 day off during a peak flow record there must be only one comple to score, a situation where the Oasys score is less sensitive and specific, but specificity still around 80%. If you would like to email the Oasys file to the website additional comments will be available

10/12/2009