Poison ivy and poison oak allergic contact dermatitis

Allergic contact dermatitis to poison ivy and poison oak is a significant problem in North America because over 50 per cent of the general population is sensitive to these plants. The sap, urushiol, contains the allergens, which are mixtures of pentadecylcatechols and heptadecylcatechols. Poison ivy and poison oak are members of the Anacardiaceae family of plants, which include poison sumac, the cashew tree, ginkgo tree, Indian marking nut tree, and mango tree. Allergic contact dermatitis in poison ivy/oak-sensitive individuals can be caused by these other Anacardiaceae members because of immunologic cross-reactions with chemically similar allergens. The efficacy of available preparations for hyposensitization against poison ivy/oak is controversial. Prevention with the topical agents linoleic acid dimers or activated organoclay holds promise for the future. When avoidance of the plant fails, the treatment of choice for the acute uncomfortable vesiculobullous eruption is topical or systemic steroids.