title: Prevalence of sensitivity to sulfiting agents in asthmatic patients.
abstract: Ingestion of sulfiting agents can induce wheezing in some asthmatic patients. However, neither the prevalence of sulfite sensitivity nor the clinical characteristics of the affected asthmatic population are known. In a prospective single-blind screening study, 120 non-steroid-dependent and 83 steroid-dependent asthmatic patients underwent challenge with oral capsules of potassium metabisulfite. Five non-steroid-dependent and 16 steroid-dependent asthmatic patients experienced a greater than 20 percent reduction in their one-second forced expiratory volume within 30 minutes following the oral challenge. Twelve of these sulfite reactors were rechallenged with metabisulfite capsules in a double-blind protocol. Under these conditions, only three of seven steroid-dependent patients had a positive response. Moreover, only one of five non-steroid-dependent patients had a response to double-blind challenge. On the basis of this challenge study, the best estimate of the prevalence of sulfite sensitivity in the asthmatic patients studied is 3.9 percent. This population, however, contained a larger number of steroid-dependent asthmatic patients than would be found in the general asthmatic population. It is concluded, therefore, that the prevalence of sulfite sensitivity in the asthmatic population as a whole would be less than 3.9 percent and that steroid-dependent asthmatic patients are most at risk.
mesh_terms: D000328:Adult; D001249:Asthma / Q000188:drug therapy / Q000276:immunology*; D002986:Clinical Trials as Topic; D004311:Double-Blind Method; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D006967:Hypersensitivity / Q000209:etiology*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011897:Random Allocation; D012306:Risk; D013256:Steroids / Q000627:therapeutic use; D013447:Sulfites / Q000009:adverse effects*
chemical_list: D013256:Steroids; D013447:Sulfites