Nasal provocation test in the diagnosis of natural rubber latex allergy

Background: Natural rubber latex (NRL) allergy in workers using rubber glov es has been an occupational health problem for the last 10 years. In the ca se of the occupational agents, clinical history may be far from conclusive; hence, appropriate provocation should be carried out. The objective was to evaluate the usefulness of the nasal challenge test in the diagnosis of al lergic rhinitis in subjects occupationally exposed to NRL. Methods: A single-blind, placebo-controlled study was conducted in 16 nurse s with respiratory symptoms (bronchial asthma and/or rhinitis) related to N RL exposure as well as positive skin prick test (SPT) response to NRL. The controls were nine nurses with asthma and/or perennial rhinitis unrelated t o NRL exposure; six atopic patients not occupationally exposed to NRL, with asthma and/or perennial rhinitis; and six healthy subjects. All the contro ls had negative results of SPT with NRL. Patients with a history of anaphyl axis or positive results of PAST to NRL were not considered in the study. T he "nasal pool" technique was used to evaluate the cellular response and ch anges in protein level and ECP concentration in nasal washings after topica l provocation with allergen or placebo. Results: A significant increase was noted in eosinophil and basophil number , albumin/total protein ratio, and ECP level only in NRL SPT-positive patie nts subjected to nasal challenge with NRL. Neither bronchial nor systemic r eactions were found after the nasal provocation with NRL. Conclusions: The nasal challenge test appears to be useful for diagnosing o ccupational rhinitis in NRL-sensitized patients.