Bronchial hyperactivity in bakers and its relation to atopy and skin reactivity

Data from literature suggests that a significant percentage of bakers develop occupational asthma and chronic obstructive bronchitis, the primary reason for this being the strong allergenic properties of flour. The aim of this study was to evaluate the prevalence of bronchial hyperactivity in bakers, as well as to correlate bronchial hyperactivity with positive skin tests and atopy. A group of 100 bakers (54 males and 46 females) employed in bread production for an average of 14.8 +/- 8.8 years, were examined from 1996 to 1999. Bronchial challenge tests with methacholine (cumulative dose of 4 mg) and flour were performed. It was considered positive if a FEV1 reduction of at least 20% from normal values had occurred. Additionally, skin prick tests were performed with wheat flour extracts, as well as standard environmental inhalation allergens. Total IgE were assessed using the ELISA method. Results showed that 11% of bakers demonstrated a positive methacholine test, 2% of bakers responded to the specific bronchial challenge test with wheat flour. The skin prick test with wheat flour was positive in 15% of bakers, while the same test using standard inhalation allergens was positive in 12% of bakers. Atopic status was found in 18% of bakers. The frequency of positive methacholine test was 33% in bakers with atopic status, compared to 6.1% (P < 0.01) in those without atopic status. Among the bakers who displayed a positive skin test to wheat flour, specific bronchial challenge test with flour was positive in two (13.3%) bakers, while no response to the bronchial challenge test with flour was observed in bakers with negative skin test. This is in agreement with known results.