Occupational allergy to wheat flour. Nasal response to specific inhalative challenge in asthma and rhinitis vs....

The purpose of the study was to compare cytological and biochemical changes in nasal lavage fluid induced by wheat flour inhalatory challenge in bakers with allergic rhinitis and with asthma accompanied by rhinitis.

A single-blind, placebo controlled study was conducted in 64 bakers with allergic rhinitis (n = 17), bronchial asthma and rhinitis (n = 24) and without occupational allergy (n = 23). Nasal washings were examined before, 30 min, 4 and 24 h after the specific provocation, wheras non-specific bronchial hyperreactivity (PC20) before and after 24 h.

A significant decrease in PC20 after the challenge test was observed only in patients with asthma and rhinitis. Eosinophil count and percentage, basophil count and the permeability index induced by specific provocation were significantly increased in both rhinitis patients and asthmatics. Moreover, the increase especially in total count and proportion of eosinophils as well as in the permeability index was more pronounced in subjects suffering from asthma and rhinitis than in those with rhinitis alone, although the changes were not statistically significant.

The results indicate the applicability of the "nasal pool" technique as a simple diagnostic procedure in flour-induced airway allergy. However, the evaluation of nasal lavage fluid, although a very sensitive and specific method of diagnosing respiratory allergic disease, cannot be used to distinguish patients with upper and lower airway allergy.