Allergic contact dermatitis from a pyridine derivative in polyvinyl chloride leather

Antimicrobial coating of household products has gained wide acceptance in Japan in the past several years. Pyridine derivatives, used as antifungal or antibacterial agents in many common products, are known to cause contact dermatitis. We present a case of severe contact dermatitis caused by a pyridine derivative used as an antifungal agent in the polyvinyl chloride (PVC) leather of a chair. An open patch test was performed with each ingredient of the PVC leather. Other products were previously eliminated from consideration based on a series of negative patch tests. The PVC leather obtained from the patientʹs chair gave a ++ reaction with evident blistering, according to the International Contact Dermatitis Research Group standard. Fifteen ingredients of the PVC leather were open patch tested; a positive reaction was found with 2,3,5,6-tetrachloro-4 (methylsulphonyl) pyridine (1% in petrolatum). Clinicians should be aware that antifungal or antibacterial agents may be increasingly incorporated into common household products and should be suspected in cases of contact dermatitis.