Journalof Wilderness Medicine 2, 178-182 (1991) ORIGINAL ARTICLE The effect of jewel weed in preventing poison ivy dermatitis B.J. ZINK, E.J. orren, M. ROSENTHAL and B. SINGAL Department of Emergency Medicine, Albany Medical College, 47 New Scotland Avenue, Albany, NY 12208, USA The treatment of poison ivy dermatitis with jewel weed (Impatiens biflora, Impatiens pallida) is a common folk remedy, which dates back to native American medicine. We designed a double blind, randomized and controlled clinical trial in human volunteers to test the effect of jewel weed juice in preventing poison ivy dermatitis. Twenty-five subjects were enrolled and had three areas on their forearms exposed to poison ivy leaves. The exposed areas received one of three applications: jewel weed juice, saline, or no agent. The subjects were assessed at 48, 72 and 96 h for severity of dermatitis and symptoms. No significant differences were found between the three categories in severity of dermatitis or degree of symptoms. With this model, it appears that jewel weed is not effective in preventing poison ivy dermatitis. Key words: poison ivy dermatitis, jewel weed Introduction Poison ivy (Toxicodendron radicans), and its close relatives poison oak and poison sumac, produce severe dermatitis in humans. A great variety of substances have been employed by medical practitioners and the general populace to prevent and treat poison ivy dermatitis. For at least 100 years, jewel weed (Impatiens bifloa, Impatiens pallida, also called the touch-me-not-plant) has been promoted in American folklore as an effective treatment for poison ivy dermatitis [1-3]. The most extensive scientific investigation of the effect of jewel weed on poison ivy dermatitis was published 40 years ago [4]. This showed a possible effect of jewel weed juice in inactivating the poison ivy toxin when the two were mixed in solution before application. One uncontrolled case series described jewel weed as very effective in treating poison ivy dermatitis; another very limited study in two subjects found that jewel weed did not prevent poison ivy dermatitis [5,6]. We undertook a randomized, double blind trial using a nested repeated measures design to determine if jewel weed is effective in preventing or ameliorating poison ivy dermatitis in humans. Materials and methods The study protocol was approved by the University of Cincinnati Medical Center Institutional Review Board. Informed consent was obtained from all study subjects. Twentyfive young adult volunteers were recruited for the study. Inclusion criteria were a minimum age of 18 years and a history of poison ivy dermatitis in the previous 12 0953-9859/91 $03.00 +.12 1991 Chapman and Hall Ltd
The effect ofjewel weed in preventing poison ivy dermatitis 179 months. Exclusion criteria were pregnancy, underlying chronic dermatologic disease, existing dermatitis, current use of systemic steroids, known poison ivy exposure in the previous 4 days, history of anaphylaxis to plant material, and known allergic reaction to jewel weed. On day 1 of the study, subjects were examined and had the volar surfaces of their forearms washed with tap water and then dried. Three 2 cm X 2 cm squares were drawn on the volar forearm (two on the left arm and one on the right) with a surgical marking pencil. Fresh poison ivy leaves were cut into 2 cm X 2 cm squares, perforated, and crushed on a metal grater. The poison ivy squares were then applied over the marked areas on the forearms and secured under an elastic bandage. After 15 min, the poison ivy squares were removed and the three areas had agents applied according to a previously assigned, randomized sequence. One area received no treatment, one was treated with jewel weed juice, and one treated with normal saline. Jewel weed juice was obtained from the crushed stems of wild Impatiens pallida plants which had been harvested on the morning of the study. Jewel weed juice and normal saline were applied with standard cotton-tipped applicators which had been soaked in the liquid. Five one-way strokes across the application area were used. Subjects closed their eyes during application of the agents. An occlusive, non-adherent dressing was applied to all three areas for 24 h. After 24 h, subjects were instructed to carryon with normal activities, including bathing, but were asked to refrain from applying creams or other treatments to the study areas. Subjects were examined at 48, 72, and 96 h after initial application by an investigator who had been blinded to the application sequence. The study areas were graded using a dermatologic scale for severity of dermatitis (Table 1). The subjects completed a subjective discomfort score sheet at each visit. Results A preliminary estimate indicated that approximately twenty patients would be needed to show no treatment effect with a power of 0.90 when p = 0.05. Twenty-five subjects were enrolled in the study. Three subjects did not develop signs of dermatitis in any of the three study areas, and were excluded from data analysis. Of the 22 remaining subjects, there were 10 females and 12 males. The age range was 18 to 43 years, with a mean of 31.5 years. Subjects reported having previous poison ivy dermatitis a mean of 11.9 times (range 1 to 30 times). Overall reactivity was good, with 20 of the 22 subjects developing at least a grade 3 dermatitis in one of the exposed areas. Five of 22 subjects exhibited a lower dermatitis severity score in the area treated with jewel weed than was present in the normal saline and no treatment areas (Table 2). Table 1. Dermatologic grading scale used for scoring the severity of dermatitis in study subjects. o= no reaction 1 = erythema and/or edema only 2 = papules and/or vesicles, 1 to 3 per square 3 = papules and/or vesicles, 4 to 8 per square 4 = papules and/or vesicles, > 8 per square 5 = confluent papules and/or vesicles
180 Zink, Otten, Rosenthal and Singal Table 2. Results ofthe Dermatitis Severity Score. The five point scale was reduced to three categories. The table lists numbers ofsubjects with corresponding severity score. Treatment 0-1 Dermatitis severity scores 2-3 4-5 No treatment Normal saline Jewel weed 1 1 3 14 13 14 7 8 5 (n = 22) Data analysis The three study areas (no treatment, jewel weed juice, saline) were tested for equivalency using Friedman rank sums and a distribution free test directed at general alternatives. No statistically significant treatment effect was found for the severity of dermatitis (s' = 1.58, p = 0.5) or the subjective discomfort (s' = 1.65, P = 0.54). Based on this analysis, jewel weed was not effective in preventing or ameliorating poison ivy dermatitis. Discussion Jewel weed has been used by native Americans for hundreds of years as a treatment for various skin conditions, including poison ivy dermatitis. Its use has also been described in American folklore and in books on herbal remedies [1-3]. Many outdoorspersons and rural inhabitants of the US Northeast are familiar with the reported benefits of jewel weed in preventing poison ivy dermatitis. The plant is commonly found in shady, wet areas. It is often noted that jewel weed and poison ivy grow in the same locations. This makes jewel weed a convenient, appealing remedy for those who believe that nature provides antidotes to plant toxins. The usual method of application by those who fear they have been exposed to poison ivy is to crush the fragile, translucent stems of the jewel weed plant, and to then rub the juice on exposed skin. There is some scientific evidence that urushiol, the toxic principle in poison ivy and other Toxicodendron species, is inactivated by jewel weed juice. The jewel weed plant, along with many other plants, has been found to contain peroxidase and polyphenol oxidase, which can decrease the potency of the pentadecylcatechols in urushiol when admixed for several hours [4]. Gibson and Maher performed extensive tests on guinea pigs and humans in the late 1940s using extracts of jewel weed juice and oxidizing enzymes derived from jewel weed juice, to both prevent and treat poison ivy dermatitis. No beneficial effect was demonstrated in guinea pigs. In human subjects, the investigators found that jewel weed juice or concentrated enzyme solutions were able partially to inactivate dilute poison ivy extracts when mixed in vitro and then applied to skin. Details of the experimental results are not included in the published report [4]. The investigators found jewel weed ineffective in treating established cases of poison ivy dermatitis in humans. Lipton reported the use of jewel weed juice, along with other medications, in 115 patients with poison ivy dermatitis who were seen over a 15 year period. He found that 108 of 115 patients treated with jewel weed preparations had complete relief of their symptoms within 2 to 3 days [5]. Guin and Reynolds tested the effect ofjewel weed juice
The effect ofjewel weed in preventing poison ivy dermatitis 181 in preventing poison ivy dermatitis on themselves, using water as a control. They found that jewel weed juice did not prevent poison ivy dermatitis [6]. In this investigation, we tried to simulate the method in which jewel weed is used by people outdoors. We used crushed, bruised poison ivy leaves rather than a prepared extract. A fifteen-minute exposure to poison ivy, followed by immediate application of jewel weed juice, parallels the manner in which jewel weed is commonly used to prevent poison ivy dermatitis. We achieved very good reactivity, with significant dermatitis in 22 of 25 subjects. In our subjects, it was clear that neither jewel weed juice nor gentle saline application was better than doing nothing as prophylactic treatment for poison ivy dermatitis. We designed the study to minimize beta error. However, in a negative study, there is still some finite chance that a true effect was not demonstrated even though one exists. We feel that this investigation was of sufficient power to detect any prophylactic effect of jewel weed that would be of clinical and practical significance. A number of factors may have contributed to the negative findings in our study. The application of jewel weed juice with a cotton tip applicator is different than the common outdoor practice of crushing jewel weed stems and rubbing them on the skin. Mechanical action may remove some poison ivy resin. Fresh jewel weed was used in the study; it is not thought that the activity of oxidizing enzymes would be reduced in the few hours until application, although this is possible. We did not analyze or test the potency of any active principles in the jewel weed juice. It is known that the potency of chemicals and enzymes in plants can vary with time of year, rainfall, and soil composition. The plants we used were mature and apparently healthy, and were collected in mid-may. Further studies on the effect of jewel weed in preventing poison ivy dermatitis might look at concentrated jewel weed juice, longer application periods, and mechanical factors during application. It should be noted that this study did not investigate the use of jewel weed as a remedy for existing poison ivy dermatitis. Conclusion There is a widely-held belief in American folklore and in the rural population of the US Northeast that jewel weed can prevent poison ivy dermatitis. This investigation does not support this belief. Jewel weed juice, when applied immediately after exposure to poison ivy, did not reduce or prevent poison ivy dermatitis in humans. Acknowledgments This study was funded by the University of Cincinnati Department of Emergency Medicine Resident Research Fund References 1. Lewis, W.H. and Elvin-Lewis, M.P.F., eds. Medical Botany: Plants Affecting Man's Health. New York: John Wiley & Sons, 1977. 2. Bolyard, J.L. Medicinal Plants and Home Remedies ofappalachia. Springfield, Ill: Charles C. Thomas Pub!., 1981. 3. Gibbons, E. Stalking the Healthful Herbs. New York: David McKay Co., Inc., 1966.
182 Zink, Otten, Rosenthal and Singal 4. Gibson, M.R and Maher, F.T. Activity ofjewelweed and its enzymes in the treatment of Rhus dermatitis. J. American Pharm Assoc 1950; 39, 294. 5. Lipton, RA. The use of Impatiens hiflora (jewelweed) in the treatment of Rhus dermatitis. Ann Allergy 1958; Sept-Oct, 526. 6. Guin, J.D. and Reynolds, R Jewelweed treatment of poison ivy dermatitis. Contact Derm 1981; 287.