Inhaled metabisulfite sensitivity.

Sensitivity to an inhaled sulfite-containing solution was evaluated in 13 asthmatics and ten nonasthmatic controls. Three of the 13 asthma patients were known to be sensitive to ingested sulfite and ten were not sensitive. All three sulfite-sensitive patients developed bronchospasm following sulfite inhalation challenges. Four of the ten asthmatics not sensitive to ingested sulfite developed bronchospasm following sulfite inhalation. The control subjects showed no reaction to inhaled sulfite. This study demonstrated that all asthmatics sensitive to ingested sulfite developed bronchoconstriction with inhaled sulfite. Furthermore, sensitivity to inhaled sulfite was more common than sensitivity to ingested sulfite in asthmatic patients. Possible reasons for this difference are discussed.