Challenge tests with tartrazine in patients with asthma associated with intolerance to analgesics (ASA-Triad). A comparative study with placebo.

In a study of the incidence of respiratory reaction to tartrazine, challenge tests were made with doses of 5, 25, 50, 100 and 200 mg of tartrazine and with a placebo, on forty-seven patients with asthma associated with intolerance to analgesics (ASA-Triad). The patient's clinical and spirographic condition was satisfactory when the test was made, and the administration of bronchodilators had been stopped 24 hr previously. In a total of 141 tests with tartrazine on forty-seven patients, only five tests were positive and occurred in only four patients. In three patients the test gave a negative result when repeated with an identical or larger dose of tartrazine. Only one patient had a respiratory reaction with 5 mg of tartrazine on two successive occasions, and this result is considered doubtful bearing in mind that the variation in FEV1 was at its limit. All the tests with placebo were negative except one. The clinical lability of the ASA-Triad patients could be the cause of some of the respiratory reactions attributed to tartrazine in some studies. The lability could, above all, be dependent on the suppression of the symptomatic treatment. The inconvenience associated with a colour-free diet and the small incidence of proven reactions to tartrazine, tend to invalidate the practice of recommending such diets unless evidence is available of a positive challenge test on at least two occasions. Even so, the risks induced are minimal.