Nasal challenge test in the diagnosis of allergic respiratory diseases in subjects occupationally exposed to a high molecular allergen (flour)

The objective of this study was the evaluation of the usefulnessof the nasal challenge test in the diagnosis of allergic respiratorydiseases in subjects occupationally exposed to flour. A single-blind,placebo controlled study was conducted in 100 subjects withoccupational atopic asthma with rhinitis. The control groupsconsisted of 20 atopic subjects not sensitized to investigatedallergens and 20 healthy subjects. A ‘nasal pool’technique was used to evaluate the changes of the cellular responseand protein level in nasal washings after topical provocationwith allergen or placebo. The concentrations of eosinophil cationicprotein and mast cell-derived tryptase in nasal fluid were evaluatedin 60 cases. There were significant increases in eosinophiland basophils number, albumin/total protein ratio, eosinophilcationic protein and tryptase levels in occupationally sensitizedpatients challenged with specific allergens. There were neithersevere bronchial reactions or an increase of bronchial hyperreactivityin occupationally sensitized patients after the nasal provocationwith flour. The nasal challenge test appears to be a very usefuland safe tool for diagnosing occupational allergy.