A quantitative study of the relation of synthetic 3-pentadecyl catechol to hypersensitiveness to rhus toxicodendron (poison ivy) as shown by the patch test

Abstract

1. 1. Sixty-two persons sensitive to the poison ivy plant were found to be sensitive to synthetic 3-pentadecyl catechol in concentrations of 1 per cent, or less, in acetone. This substance is the saturated analogue of the active ingredient causing poison ivy dermatitis. 2. 2. Quantitative studies in twenty-one subjects sensitive to poison ivy showed that a 0.1 per cent concentration of 3-pentadecyl catechol in acetone is suitable to detect those sensitive to the poison ivy plant, and probably also, related plants; however, for final evaluation a period of ninety-six hours of observation is requisite. The advantage of using this concentration is that severe reactions are eliminated for the most part. There are occasional instances in which, after ninety-six hours, a 1 per cent concentration may be used to reveal the exceptionally mildly sensitive patient who fails to react to a 0.1 per cent concentration. 3. 3. The advantages of using synthetic 3-pentadecyl catechol as a replacement for ground poison ivy leaves or extract in testing for hypersensitiveness to Rhus toxicodendron have been pointed out. It is suggested that in a suitable vehicle and concentration this substance may be used in an attempt to desensitize persons sensitive to the poison ivy plant and its congeners. 4. 4. The principle of group specific reactions is amply illustrated in the case of 3-pentadecyl catechol in its relation to the active ingredient in poison ivy dermatitis.