Allergic contact dermatitis to shoes induced by dimethylfumarate: A new allergen imported from China.

BACKGROUND In the last two years several cases of severe contact dermatitis related to newly acquired sofas and armchairs originating from China have been published. The responsible allergen is dimethylfumarate (DMF), an extremely potent sensitizer and irritant found in sachets inside the furniture. Recently, cases of contact dermatitis related to shoes and riding helmets have also been described. METHODS We evaluated two patients with allergic contact dermatitis related to shoes manufactured in China that were contaminated by dimethylfumarate found in sachets placed inside the shoeboxes. RESULTS Patch tests with DMF extracted from the sachets inside the shoeboxes showed positive reactions. Postitive reactions were also obtained using small fragments of the shoes and tissue of the "MouldProof" sachet. The patients were instructed to avoid the suspected shoes and were treated with topical corticosteroids. CONCLUSIONS Contact dermatitis induced by dimethylfumarate should be suspected in appropriate cases. It is important to remember that this allergen is not included in most series for patch testing.