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Poison ivy (Toxicodendron) dermatitis

Lori Prok, MD
Thomas McGovern, MD
Section Editors
Robert P Dellavalle, MD, PhD, MSPH
Daniel F Danzl, MD
Joseph Fowler, MD
Deputy Editor
Rosamaria Corona, MD, DSc


Exposure to plants of the Anacardiaceae family account for more allergic contact dermatitis than all other plant families combined. In the United States, the most important members of this family are those of the genus Toxicodendron (previously classified as in the genus Rhus [1,2]), which include common or northern poison ivy (Toxicodendron radicans), western poison ivy (Toxicodendron rydbergii), eastern poison oak (Toxicodendron toxicarium), western poison oak (Toxicodendron diversilobum), and poison sumac (Toxicodendron vernix). Toxicodendron means "poisonous tree," an appropriate choice for these dermatitis-provoking species. In contrast, although they often have three-leaflet configurations similar to those of Toxicodendron, members of the genus Rhus are nonallergenic [1,2]. Throughout this topic review, we refer to Toxicodendron dermatitis by the common name "poison ivy dermatitis."

This topic reviews the epidemiology, prevention, and treatment of allergic contact dermatitis due to these Toxicodendron species. The evaluation and management of contact dermatitis from other causes is discussed separately (see "Overview of dermatitis", section on 'Contact dermatitis'). Despite the prevalence of poison ivy dermatitis in the United States, there are very few well-designed, published studies examining the management of this condition.


Many people are sensitized to urushiol, the allergenic compound found in poison ivy, poison oak, and poison sumac. Fifty percent of people will react to poison ivy in nature, and approximately 75 percent will react to patch testing with urushiol. Annually, an estimated 25 to 40 million Americans require medical treatment after exposure [3,4]. Firefighters, forestry workers, and farmers constitute a large proportion of the victims affected through occupational exposure, and this can have important occupational and economic impacts [4,5].

Poison ivy dermatitis affects all ethnicities and skin types, and most geographical regions in the United States are at risk [6] (see 'Geography' below). Children are also affected; most children over the age of eight years are sensitized [4]. Allergic responsiveness to poison ivy appears to wane with age, especially in those with mild reactions and limited sensitizing exposures.


While the common phrase "leaves of three, let them be" is a helpful reminder to avoid poison ivy and related plants, members of the Toxicodendron genus have varied presentations based on the season, growth cycle, region, and climate (figure 1 and picture 1A-C) [7].

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Literature review current through: Sep 2017. | This topic last updated: Feb 05, 2016.
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  1. Crawford GH, McGovern TW. Poison ivy. N Engl J Med 2002; 347:1723.
  2. McGovern TW, Barkley TM. Botanical dermatology. Int J Dermatol 1998; 37:321.
  3. Baer RL. Poison ivy dermatitis. Cutis 1990; 46:34.
  4. Epstein WL. Occupational poison ivy and oak dermatitis. Dermatol Clin 1994; 12:511.
  5. Oltman J, Hensler R. Poison oak/ivy and forestry workers. Clin Dermatol 1986; 4:213.
  6. Fisher AA. Poison ivy/oak/sumac. Part II: Specific features. Cutis 1996; 58:22.
  7. Parkinson G. Images in clinical medicine. The many faces of poison ivy. N Engl J Med 2002; 347:35.
  8. Hershko K, Weinberg I, Ingber A. Exploring the mango-poison ivy connection: the riddle of discriminative plant dermatitis. Contact Dermatitis 2005; 52:3.
  9. Rademaker M, Duffill MB. Allergic contact dermatitis to Toxicodendron succedaneum (rhus tree): an autumn epidemic. N Z Med J 1995; 108:121.
  10. Cohen LM, Cohen JL. Erythema multiforme associated with contact dermatitis to poison ivy: three cases and a review of the literature. Cutis 1998; 62:139.
  11. Shankar DS. Contact urticaria induced by Semecarpus anacardium. Contact Dermatitis 1992; 26:200.
  12. Kurlan JG, Lucky AW. Black spot poison ivy: A report of 5 cases and a review of the literature. J Am Acad Dermatol 2001; 45:246.
  13. McGovern TW. Dermatoses due to plants. In: Dermatology, Bolognia JL, Jorizzo JL, Rapini RP, et al (Eds), Mosby, New York 2003. p.274.
  14. Brook I, Frazier EH, Yeager JK. Microbiology of infected poison ivy dermatitis. Br J Dermatol 2000; 142:943.
  15. Devich KB, Lee JC, Epstein WL, et al. Renal lesions accompanying poison oak dermatitis. Clin Nephrol 1975; 3:106.
  16. Stibich AS, Yagan M, Sharma V, et al. Cost-effective post-exposure prevention of poison ivy dermatitis. Int J Dermatol 2000; 39:515.
  17. Epstein WL. Topical prevention of poison ivy/oak dermatitis. Arch Dermatol 1989; 125:499.
  18. Marks JG Jr, Fowler JF Jr, Sheretz EF, Rietschel RL. Prevention of poison ivy and poison oak allergic contact dermatitis by quaternium-18 bentonite. J Am Acad Dermatol 1995; 33:212.
  19. Grevelink SA, Murrell DF, Olsen EA. Effectiveness of various barrier preparations in preventing and/or ameliorating experimentally produced Toxicodendron dermatitis. J Am Acad Dermatol 1992; 27:182.
  20. Liu DK, Wannemacher RW, Snider TH, Hayes TL. Efficacy of the topical skin protectant in advanced development. J Appl Toxicol 1999; 19 Suppl 1:S40.
  21. Vidmar DA, Iwane MK. Assessment of the ability of the topical skin protectant (TSP) to protect against contact dermatitis to urushiol (Rhus) antigen. Am J Contact Dermat 1999; 10:190.
  22. Fisher AA. Poison ivy/oak dermatitis. Part I: Prevention--soap and water, topical barriers, hyposensitization. Cutis 1996; 57:384.
  23. Marks JG Jr, Trautlein JJ, Epstein WL, et al. Oral hyposensitization to poison ivy and poison oak. Arch Dermatol 1987; 123:476.
  24. Williford PM, Sheretz EF. Poison ivy dermatitis. Nuances in treatment. Arch Fam Med 1994; 3:184.
  25. Epstein WL, Byers VS, Frankart W. Induction of antigen specific hyposensitization to poison oak in sensitized adults. Arch Dermatol 1982; 118:630.
  26. Rietschel RL. A pilot study of pentoxifylline for the prevention of poison ivy/oak reactions. Contact Dermatitis 1995; 32:365.
  27. Schwarz T, Schwarz A, Krone C, Luger TA. Pentoxifylline suppresses allergic patch test reactions in humans. Arch Dermatol 1993; 129:513.
  28. Schwarz A, Krone C, Trautinger F, et al. Pentoxifylline suppresses irritant and contact hypersensitivity reactions. J Invest Dermatol 1993; 101:549.
  29. KLIGMAN AM. Poison ivy (Rhus) dermatitis; an experimental study. AMA Arch Derm 1958; 77:149.
  30. Davila A, Lucas J, Jacoby J, et al. A new topical agent, Zanfel, ameliorates urushiol-induced Toxicodendron allergic contact dermatitis. Ann Emerg Med 2003; 42:S98 (Abstract).
  31. Amrol D, Keitel D, Hagaman D, Murray J. Topical pimecrolimus in the treatment of human allergic contact dermatitis. Ann Allergy Asthma Immunol 2003; 91:563.
  32. Munday J, Bloomfield R, Goldman M, et al. Chlorpheniramine is no more effective than placebo in relieving the symptoms of childhood atopic dermatitis with a nocturnal itching and scratching component. Dermatology 2002; 205:40.
  33. Yosipovitch G, Fleischer A. Itch associated with skin disease: advances in pathophysiology and emerging therapies. Am J Clin Dermatol 2003; 4:617.
  34. Vernon HJ, Olsen EA. A controlled trial of clobetasol propionate ointment 0.05% in the treatment of experimentally induced Rhus dermatitis. J Am Acad Dermatol 1990; 23:829.
  35. Goodall J. Oral corticosteroids for poison ivy dermatitis. CMAJ 2002; 166:300.
  36. Moe JF. How much steroid for poison ivy? Postgrad Med 1999; 106:21, 24.
  37. Brodell RT, Williams L. Taking the itch out of poison ivy. Are you prescribing the right medication? Postgrad Med 1999; 106:69.
  38. Dickey RF. Parenteral short-term corticosteroid therapy in moderate to severe dermatoses. A comparative multiclinic study. Cutis 1976; 17:179.
  39. Long D, Ballentine NH, Marks JG Jr. Treatment of poison ivy/oak allergic contact dermatitis with an extract of jewelweed. Am J Contact Dermat 1997; 8:150.