[The skin prick test and nasal provocation test with individually prepared flour extracts in patients with bakers' rhinitis and asthma].

The reliability of skin prick tests (SPT) may be insufficient for the screening of occupational inhalant allergies. The influence of different flour extracts on the SPT in flour allergic subjects has not been compared previously. In this study, SPT reactions against two commercially available rye and wheat flour extracts and individually prepared extracts from flour samples were compared in 35 patients with known bakers' rhinitis. Flour sensitization was confirmed by a positive nasal provocation test (NPT) and/or serum-specific IgE. The sensitivity of NPT with a combination of rye and wheat flour extracts of individual flour samples was 94%. Wheat and/or rye flour specific IgE (RAST>/=2) was true positive in 86%. The sensitivity of the SPT was 94% for individual rye flour extracts compared to 38% and 59% for two commercially available rye flour extracts and 88% for individual wheat flour extract compared to 53% and 48% for commercially available wheat flour extracts. SPT and sIgE did not reveal a significant difference in prevalence between rye and wheat flour sensitization. Thirty healthy volunteers served as the control group. Three control subjects with histamine equivalent SPT reactions to grass pollen had a positive SPT reaction against individual flour extracts, whereas NPT with undiluted individual flour extracts was negative in all controls. SPT with individually prepared flour extracts appears to be sensitive for the demonstration of inhalant flour allergy. Our findings show that extracts of individual flour samples rather than commercially available extracts should be used for both SPT and NPT if flour allergy is suspected.