[Asthma and rhinoconjunctivitis caused by rape flour: description of a clinical case]. / Asma e rinocongiuntivite da farina di colza: descrizione di un caso clinico.

A 48 year old man, employed in a grain and animal feed store for 9 years, was referred to our clinic complaining of nasal blockage, rhinorrhea, sneezing, ocular burning, coughing and wheezing occurring over the last 12 months. The man's main task was to manually load and unload the unpackaged grain and feed. Symptoms occurred only when he worked directly with oilseed rape flour and not when he worked with other types of grains. Eye and nasal symptoms appeared during the work shift, while respiratory symptoms were worse at night than during the day after exposure to rape for more than 2 consecutive days. Physical examination was normal, as were the results of the pulmonary function studies. The methacholine inhalation test, performed to measure the level of non-specific airways responsiveness, showed normal bronchial reactivity. Results of allergy skin prick tests were negative for common inhalant and food allergens, but slightly positive for the oilseed rape flour extract. Registration of the peak expiratory flow (PEF) showed slight decreases in PEF values after occupational exposure. We conclude that this case is suggestive of asthma and rhino-conjunctivitis, induced by oilseed rape flour, probably due to an allergic mechanism.

Late, but not early, asthmatic reactions induced by toluene-diisocyanate are associated with increased airway responsiveness to methacholine.

We investigated whether airway responsiveness to methacholine differs in subjects with a history of sensitization to TDI who develop immediate, dual, late, or no asthmatic reactions after exposure to TDI, and also the effect of a TDI inhalation challenge in asthmatic subjects with hyperreactive airways with no history of sensitization to TDI. We measured FEV-1 immediately before and after exposure to TDI (0.018 ppm; 5-30 min) and then hourly for 8 h and the provocative dose (mg) of methacholine that caused a decrease in FEV-1 of 20% (PD20 FEV-1). The results of the present study suggest that the bronchoconstrictor effect of isocyanates is specifically linked to exposure to TDI and subsequent sensitization, excluding a nonspecific irritant effect on the airways. Moreover, they suggest that the increase in airway responsiveness to methacholine associated with the late asthmatic reaction is linked to factors that cause the late component of the asthmatic reaction.

Prednisone inhibits late asthmatic reactions and the associated increase in airway responsiveness induced by toluene-diisocyanate in sensitized subjects.

To determine whether late asthmatic reactions and the associated increase in airway responsiveness induced by toluene diisocyanate (TDI) are linked to airway inflammation, we investigated whether they are inhibited by prednisone. Ten "sensitized" subjects were studied in 2 sets of experiments. In the first set, each subject was given no treatment and was studied before and for 8 h after exposure to TDI. In the second set, 2 to 4 wk later, each subject was studied before treatment and then during treatment with prednisone (50 mg once a day for 3 days, orally), both before and after exposure to TDI. To assess late asthmatic reactions to TDI, we measured FEV1 immediately before and after exposure, then hourly for 8 h. To assess changes in airway responsiveness, we measured the provocation dose (mg) of methacholine causing a 20% decrease in FEV1 (PD20FEV1) before and 8 h after exposure to TDI. When the subjects received no prednisone treatment, TDI caused late asthmatic reactions and increased airway responsiveness. By contrast, when the subjects received prednisone, TDI caused no late asthmatic reaction or increased airway responsiveness. Prednisone did not change baseline airway caliber or airway responsiveness. These results suggest that late asthmatic reactions and the associated increase in airway responsiveness induced by TDI in "sensitized" subjects may depend on the development of a steroid-responsive acute inflammatory reaction within the airways.