In susceptible individuals lesions may appear within 12-24 hours. New lesions may continue to appear for up to 2-3 weeks. Toxicodendron dermatitis is the most common cause of contact dermatitis in the US, exceeding all other causes combined. However, the most prevalent form of plant dermatitis worldwide occurs from exposure to the numerous members of the family Compositae and varied sesquiterpene lactone allergens from these plants. Morbidity ranges from localized mild erythema and pruritus to diffuse erythema, edema, severe pain, and pruritus with bullous lesions.
Secondary infection can complicate the dermatitis.
People of color tend to be less sensitive. The dermatatitis is highly variable and depends on the sensitivity of the patient and extent of exposure. In mild cases, classic lesions on exposed skin are secondary to brushing against the plant or excoriations from scratching with contaminated fingernails. Bullae Erythema multiforme is an atypical presentation of toxicodendron dermatitis. Other urushiol containing plants include cashew nut tree, mango tree, and ginkgo tree.