Wood dust from jelutong (Dyera costulata) causes contact allergy

Jelutong is the wood from Dyera costulata growing in south-east Asia. It is soft and easy to work and is used in, e.g., model workshops in car factories. It has also been much used in woodwork teaching in Swedish comprehensive schools. To estimate the prevalence of contact allergy to jelutong, 84 woodwork teachers and 110 consecutive dermatitis patients were patch tested with extract from wood dust of jelutong. 16/84 (19%) teachers had positive reactions. When they were tested with a dilution series, positive reactions were obtained for 6 mg and down to 0.3 mg of the extracted material. Half the test-positive teachers had skin symptoms that might be related to exposure to jelutong 4/110 dermatitis patients at the clinic also had positive reactions, and possible exposure to jelutong was traced in 3 of them. 3 other dermatitis patients had flare-up reactions after about 2 weeks, indicating patch-test sensitization. To investigate the sensitizing capacity of the extract, the cumulative contact enhancement test was performed in guinea pigs. This confirmed that the extracted material was sensitizing, and a clear dose-response relationship was found. The schools will be recommended to use safer wood alternatives in woodwork teaching.