The cause of the Chinese sofa/chair dermatitis epidemic is likely to be contact allergy to dimethylfumarate, a novel potent contact sensitizer

BACKGROUND: A small epidemic of severe contact dermatitis cases related to newly acquired sofas and chairs has surpassed the news threshold in Finland and the U.K. OBJECTIVES: To study affected patients and to identify the cause. METHODS: Five patients with contact dermatitis related to a newly purchased chair or sofa were studied. Furniture samples were analysed by gas chromatography-mass spectrometry. Compounds were identified using a mass spectrum library and measured semiquantitatively. Patch tests were performed with commercial standard allergens, furniture upholstery and chemicals found in the analysis. RESULTS: Patch tests with commercial allergens did not solve the problem. Up to 470 microg kg(-1) of dimethylfumarate was found in chairs. The patients showed strong positive patch test reactions to upholstery fabric samples and to dimethylfumarate, down to a level of 1 p.p.m. in the most severe case. CONCLUSIONS: The cause of the Chinese sofa/chair dermatitis epidemic is likely to be contact allergy to dimethylfumarate, a novel potent contact sensitizer.