poison ivy dermatitis [L, potio, drink; ME, ivi + Gk, derma, skin, itis, inflammation] , an allergic contact dermatitis caused by exposure to a nonvolatile oil, toxicodendrol, present in the leaves and other plant parts of poison ivy, a member of the Rhus toxicodendron species. Other Rhus species producing the same kind of contact dermatitis are poison oak and poison sumac. Also called rhus dermatitis.
