Causes of hypersensitivity reactions in flour mill workers in Sudan

A study of 237 male workers at two flour mills and 71 controls was carried out in Sudan in order to investigate the main possible causes of hypersensitivity reactions to flour dust. Statistical analysis was carried out for the skin test results of wheat, mixed moulds (A13), grain dust, and mixed moulds (group MH) allergen extracts. The results showed that there was no statistical significance between the two exposed groups namely allergy complaining vs. allergy non-complaining except for wheat results in one of the two flour mills which was very slightly significant. But there were highly significant differences between the exposed compared with the control group in all allergens tested. There was no significant correlation, between allergic symptoms and precipitins to wheat or grain dust, nor between precipitins and positive skin tests. The results of respirable flour dust concentrations at different work locations had exceeded the threshold limit values which were taken as 10 mg/m3. Aspergillus supp. and Rhizopus niger were the predominant fungi in the wheat grains and products which were collected from the two mills.