Reactive dye (RD) induced bronchial asthma is a well known form of occupational asthma. We report a case of occupational asthma due to RD in an exposed worker near a dye factory.

To evaluate the work-relatedness of bronchial asthma, we examined all possibilities by considering the working environment and performing a personal clinical survey, such as interview on the previous history of allergic diseases, clinical and immunological investigation including skin prick tests, bronchoprovocation tests, and serial peak expiratory flow rates (PEFR).

Occupational asthma of internal origin was excluded by the characteristics of asthma, absence of occupational allergens, and negative PEFR result in the worker's own workplace. However, specific IgE and skin prick tests with reactive dye allergens were all strongly positive. RD challenge test showed maximal 34 % fall of FEV1 at 10 minutes of exposure (PD2 0: 2.11 mg/ml).

We concluded that this case was an example of bronchial asthma by external occupational allergens. This case suggests that RD induced asthma may also occur in workers and inhabitants who have lived near a reactive dye manufacturing factory.