On the persistence of positive patch test reactions to balsam of Peru, turpentine and nickel

Abstract

SUMMARY A group of 105 patients with positive patch test reactions to turpentine, balsam of Peru or nickel were re‐examined after periods of 2–15 years. Of twenty‐eight patients who had shown positive patch test reactions to turpentine eighteen gave negative reactions; of twenty persons formerly positive to balsam of Peru ten had become negative. Of fifty‐seven patients who had formerly been positive to nickel eighteen gave negative reactions. The implications of these findings in relation to the time factor and the possibility of avoidance of the allergen are discussed.