RESUMO
OBJECTIVES: Chloramine T is a known sensitising agent in the occupational environment of health care workers. In cases of occupational hazards induced by this agent, a clinical history may be far from conclusive, hence appropriate provocation tests are absolutely essential. The aim of the study was to evaluate the usefulness of the nasal challenge test in diagnostics of respiratory allergy to chloramine T. MATERIALS AND METHODS: A single-blind, placebo-controlled study was conducted in 6 subjects with chloramine T asthma and rhinitis. Two control groups comprised 7 atopic subjects with asthma and rhinitis and 6 healthy persons. All the controls had negative results of skin prick tests with chloramine T and none displayed any respiratory symptoms under exposure to the agent. A "nasal pool" technique was used to evaluate morphological and biochemical parameters (mast cell tryptase, eosinophil cationic protein, permeability index) in nasal washings before and 30 min, 4 h and 24 h after the provocation with chloramine T and placebo. RESULTS: A significant increase was found in the total count and percentage of eosinophils and basophils, albumin, tryptase and eosinophil cationic protein levels in the nasal lavage fluid from patients with chloramine T respiratory allergy when compared to both control groups. Also a dual asthmatic reaction in 4 patients and an isolated late reaction in 2 cases were observed in chloramine-sensitive subjects. CONCLUSIONS: The results indicate the applicability of the "nasal pool" technique as a diagnostic procedure in chloramine T-induced airway allergy.
