[Influence of ketotifen on IgE-mediated cutaneous test reactions (author's transl)]

The influence of ketotifen on IgE-mediated skin reactivity was investigated in two studies in 20 and 14 adolescent patients with pollen allergy. In the first intraindividual, double-blind randomised study, ketotifen showed a significant decrease (P less than 0.001) of the prick test weal by 38% after a 3-day-medication of 1 mg b.i.d. orally. A minimal reduction of weal size after DNCG and placebo was not significant. The second investigation showed a decrease of weal size by 20% 14-16 hours after cessation of a 7-day-medication with ketotifen. The weal size was smaller by 10% after 3 days and by 5 or 7 days it has reached pretreatment size again. For practical allergological purposes it is concluded that ketotifen should be withdrawn three days before diagnostic skin testing because of its antianaphylactic, antihistaminic and antiallergic effects.