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 usefulness of the nasal challenge test in the diagnosis of allergic respiratory diseases in subjects occupationally exposed to flour. A single-blind, placebo controlled study was conducted in 100 subjects with occupational atopic asthma with rhinitis. The control groups consisted of 20 atopic subjects not sensitized to investigated allergens and 20 healthy subjects. A 'nasal pool' technique was used to evaluate the changes of the cellular response and protein level in nasal washings after topical provocation with allergen or placebo. The concentrations of eosinophil cationic protein and mast cell-derived tryptase in nasal fluid were evaluated in 60 cases. There were significant increases in eosinophil and basophils number, albumin/total protein ratio, eosinophil cationic protein and tryptase levels in occupationally sensitized patients challenged with specific allergens. There were neither severe bronchial reactions or an increase of bronchial hyperreactivity in occupationally sensitized patients after the nasal provocation with flour. The nasal challenge test appears to be a very useful and safe tool for diagnosing occupational allergy.