[Chronic urticaria. Provocation test].

Sixty patients of ages ranging from 11 to 64, with chronic urticaria from 2 months to 50 years duration, were studied with the provocation test. We found responses in 33.3% of patients. Tartrazine was the most common inducer, specially in those patients sensitive to aspirin with increased salicilate blood levels. As we did not use aspirin as inducer the results with tartrazine are more relevant and can be used to detect a positive response to aspirin. The relation between tartrazine and aspirin was not observed in patients with pressure or cholinergic urticaria. The provocation test is most useful in patients with chronic urticaria of unknown cause. 4 hydroxybenzoic acid and sodium acid and sodium benzoate were the more common inducers in the latter patients. We feel that the provocation test is a useful tool to study patients with chronic urticaria. Tartrazine, 4 hydroxybenzoic acid, sodium benzoate, tiramin and penicilin are included in the test. The responders should eliminate the offender from their diet.