ANACARDIACEAE

The Anacardiaceae or cashew family comprises some 800+ tropical trees, shrubs or climbers with alternate leaves, small flowers and resinous bark that is irritating to the skin. Some species produce fruits called drupes (fleshy fruit with thin skin and a single seed at the center) which are valued as food such as the cashew nut, pistachio, and mango. Others like the Chinese lacquer tree produces thick sticky resin that is used as a varnish. Many Anacardiaceae species including the mango and cashew are poisonous to humans due to the presence of phenolic oleoresins (oil) called urushiols. The urushiols induce a type of skin allergy called contact dermatitis, which gets worse following repeated exposure. Urushiol dermatitis is cross-species reactive, a patient who is allergic to one species of Anacardiaceae can be triggered by many others, even without prior exposure. Infamous examples of urushiol containing species include the poison ivy, poison sumac and poison oak of the New World, as well as the Renghas tree (Gluta spp.) of Southeast Asia. 

 

Cashew nut tree (Anacardium occidentale)