Contact allergy to the Brazilian rosewood substitute Machaerium scleroxylon Tul. (Pao ferro).

Five carpenters in a television set factory had allergic contact dermatitis of the hands, forearms and neck after contact with the sawdust of the Brazilian rosewood substitute Machaerium scleroxylon Tul. (Pao ferro). Patch tests with R-3,4-dimethoxydalbergione from Pao ferro and with two other dalbergiones from rosewood species were positive. R-3,4-dimethoxydalbergione isolated from the Pao ferro sample was shown to be a strong sensitizer and thus to be responsible for these cases of contact allergy.