Role of acetyl salicylic acid and sodium metabisulfite in chronic childhood asthma.

The role of a commonly ingested food additive, the preservative sodium metabisulfite (MBS), and aspirin (ASA), in chronic asthma has been studied in 29 children. After 1 week on a strict elimination diet, all 29 children were challenged, in a single-blind fashion, in the pulmonary function laboratory on three consecutive days with placebo, MBS (capsule form and solution), and ASA. Children with a positive response to MBS were prescribed a diet that excluded foods containing MBS. Patients with a positive response to ASA were prescribed a diet excluding medications containing aspirin and natural salicylates. After 3 months on these restricted diets, the children were reassessed to determine whether there had been any therapeutic response. There was a 66% (19/29) incidence of positive challenge (greater than 20% decrease in forced expiratory volume in one second) with MBS and a 21% (6/29) incidence of positive challenge with ASA. None of the children reacted to MBS in capsule form (maximum dose = 100 mg), but 19/29 reacted to MBS in solution with 30 mL of 0.5% citric acid. After 3 months on the restricted diet, four of 19 children on the MBS-free diet and one of six on the salicylate-free diet had objective signs of improvement, namely, reduction in asthma medications and/or improvement in lung function. Unfortunately, compliance with the restrictive diet during this 3-month period was poor, particularly with the ASA-sensitive children.(ABSTRACT TRUNCATED AT 250 WORDS)