Prevalence and Clinical Significance of New Sensitization to Inhalant Allergens in Toluene Diisocyanate- induced Asthmatic Patients

Abstract

Background: It has been reported that half of toluene diisocyanate (TDI)-induced asthma patients had persistent asthmatic symptoms even after complete avoidance. We hypothesized that new sensitization to common inhalant allergens may contribute to persistent and aggravation of asthmatic symptoms. Objective: The aim of this study is to investigate the prevalence and clinical significance of new sensitization to common inhalant allergens in patients with TDI-induced asthma. Methods: Thirty-six TDI-induced asthma patients who had been followed up for more than three years were enrolled. They were classified into two groups, newly-sensitized and not-sensitized groups, according to the results of the skin- prick test and serum specific IgE antibodies to common inhalant allergens monitored every year. The clinical features, drug requirements for systemic steroids, and airway hyper responsiveness were compared between the two groups. Results: Thirteen (36.1%) of 36 patients with TDI-asthma developed new sensitization to common inhalant allergens during the follow-up periods. The mean onset time were 4.93+/-2.49 years. The prevalence of atopic status and allergic rhinitis tended to be higher in the newly sensitized group. The duration of asthmatic symptoms before the diagnosis was significantly longer in the newly sensitized group (P<0.05). The drug requirements for systemic steroids tended to increase after the new sensitization in the newly sensitized group. Conclusion: The development of new sensitization to common inhalant allergen in TDI-asthma may be associated with chronic persistent asthmatic symptoms. New sensitization to common inhalant allergens should be monitored regularly in TDI-induced asthmatic patients.