Allergen Exposure. Geographical distribution. The Cashew nut comes from the Cashew nut tree, a member of the Anacardiaceae family, which includes a number of dermatitis-inducing plants such as poison ivy, poison oak, poison sumac and lacquer sumac. The tree is native to Brazil but is grown in other parts of the world, and the nut is now also exported from southern India, Mozambique, Tanzania ...