Observations on Sensitivity to Poison Ivy

Abstract

The evidence which indicates that dermatitis due to poison ivy is an allergic phenomenon is as follows: 1. Infants and young children are not sensitive to the first exposure (1) but may be made sensitive by exposure to poison ivy extracts (2). 2. The Esquimos of Baffin Land (who do not have contact with poison ivy) are not sensitive (3) whereas a large proportion of adults living in regions in which poison ivy is abundant are sensitive in varying degree (4). 3. Adults who are not sensitive may sometimes (but not always) be made so by exposure to poison ivy extract (5). 4. Lesions simulating, to some extent, those of clinical ivy dermatitis have been reproduced in guinea pigs (6) and monkeys (7) by second applications of poison ivy extract. We report herewith our observations on three aspects of the problem of ivy sensitivity, namely: (1) its origin and development, (2) the effect of certain local applications on the clinical course of the lesions, and (3) the effect of parenteral injections of poison ivy extract on specific skin sensitivity as determined by contact tests made before and after the injections.