Oral challenge with balsam of Peru

A placebo-controlled, double-blind, oral challenge with balsam of Peru was carried out in 221 patients with various types of dermatitis. 210 patients completed the study, and 45 of them experienced a flare of their symptoms after challenge with balsam of Peru but not after placebo. 15 patients reacted to the placebo, and 5 reacted to both balsam and placebo. Specific reactivity to balsam of Peru was seen particularly in patients with positive patch tests to this compound and in some patch-test-negative patients with vesicular hand eczema, ano-genital and axillary eczema. Dietary restriction of the intake of balsams was followed by marked improvement or clearance of the dermatitis in approximately half of the patients who adhered to the diet for at least 1 month.