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Leaves of Three, How Bad Can It Be? CAITLIN A. COCHRAN, BS; DANIELLE KEYES, MPH; CAROLINE DOO, MD; THY HUYNH, MD; JULIE WYATT, MD
Abstract Figure 1.
Poison ivy is a common cause of allergic contact dermatitis. A rare phenomenon, black spot poison ivy, presents with poison ivy covered by black lacquer-like deposits. Another equally rare phenomenon is the development of erythema multiforme in association with severe poison ivy.1-4 The treatment of mild poison ivy contact dermatitis usually requires only topical therapies, but more severe cases require systemic approaches.1,5 A 36-year-old male with black spot poison ivy treated with topical, intramuscular, and oral steroids who subsequently developed secondary erythema multiforme is presented. Key Words: Allergic contact dermatitis; Toxicodendron species; Black spot poison ivy; Erythema multiforme Introduction Dermatitis caused by the Anacardiaceae family includes poison ivy, poison oak, and sumac. This accounts for more cases of contact dermatitis than all other plants combined.6 More specifically, the genus Toxicodendron contains a majority of the allergenic species including those previously mentioned.7 Medical treatment is required for 25 to 40 million Americans each year.1,8 The allergen associated with the delayed type hypersensitivity reaction of Toxicodendron allergic contact dermatitis is a phenolic lipid known as urushiol.1 Patients and primary care physicians can generally appreciate the severe itching and classic linear papulovesicular rash of poison ivy. A rare presentation, black spot poison ivy, is more commonly overlooked. Another rare phenomenon that has been associated with poison ivy is secondary erythema multiforme.2-4,9 This phenomenon has been reported in individuals with more severe poison ivy allergic contact dermatitis and may represent an underreported association.2 A rebound effect can occur following treatment with both topical and systemic corticosteroids when the course of treatment is too short.1,7
Patient’s left volar forearm on day 1 depicting erythematous plaque with ulceration and black spots.
Figure 2.
Case Summary A 36-year-old male presented with a two-week history of rash on the left forearm and a secondary rash on the abdomen following contact with a vine which he documented with a series of four “selfies.” (Figure 1 and 2)
400 VOL. 59 • NO. 9 • 2018
Patient’s left volar forearm on day 3 depicting erythematous plaque with ulceration and black spots with vesicles and crust.
