Hypersensitivity to sodium hypochlorite.

Sodium hypochlorite (NaOCl), the most commonly used irrigant in endodontics, is known to produce allergic reactions. This fact, however, is rarely mentioned in endodontic texts. Until now, only two cases of adverse reaction describing accidental injection of NaOCl have been reported. In the current study a case is presented in which hypersensitivity to household bleach was proven with skin patch tests. The clinician was warned of the possible health hazard from using NaOCl in this patient by the past medical history. Endodontic therapy was carried out with an irrigant not containing NaOCl after the allergy to NaOCl was verified. Treatment was uneventful. It is suggested that before any endodontic treatment in which sodium hypochlorite is to be used, the patient should be asked about hypersensitivity to household bleaching materials.