Occupational asthma to dried tobacco leaves: A very delayed diagnosis!

Several cases of occupational asthma to tobacco dust have been described in cigarette factories among active workers. The case we reported has the particularity to have been confirmed after a long time since end of exposure. A 59 year-old woman, never smoker, without known history of atopy, was seen in our department in 2011 for the possible diagnosis of occupational asthma (OA). She was employed as a production agent in a cigarette fabrication facility between 1986 and 2000. Some months after hire, she described the apparition of cough, dyspnea and wheezing, closely related to work periods. In 1991, a first clinical check-up retained the diagnosis of asthma. Despite a treatment, symptoms remained unchanged until the end of her job in 2000. After that, she had no longer respiratory exposures to allergens or irritants, and symptoms first decreased. Nonetheless, some years after, she described a progressive worsening of her asthma. In our department, we observed negative skin prick tests to airborne allergens and tobacco leaves (after humidification) but low positive sIgE for tobacco leaves at 0.21 kUa/L. After a negative inhalation control test to lactose powder, we organized a specific inhalation challenge (SIC) by pouring two cups of 20g of tobacco leave powder. A strong immediate positive reaction appeared after 10 min of cumulated exposure, with 42% decreasing of FEV1 relative to baseline that speaks in favor of the diagnosis of OA. Even if the end of exposure is often reported to be a cause of negative SIC, our observation suggests that a positive reaction may occur after a long time since end of exposure. Moreover, clinicians have to be aware that functional respiratory reactions could be severe.