[Toxic contact dermatitis due to the quaternary ammonium compound benzalkonium chloride (author's transl)].

A 20-year-old soldier caught an eczematous contact dermatitis on the left ear after the protection of hearing "Selektone" had been adapted. The protection of hearing had been disinfected before in a Zephirol solution 1% aqueous. Zephirol contains the quaternary ammonium compound Benzalkonium chloride. The problems of patch testing with Benzalkontium chloride are discussed.