Chlorhexidine--still an underestimated allergic hazard for health care professionals.

Chlorhexidine is a low molecular weight occupational sensitizer that can cause different delayed and immediate-type allergic reactions including anaphylaxis. It is widely used as an antiseptic and disinfectant and not only in the occupational environment as it is present in toothpaste, mouthwash, nose and eye drops and ointments. We present three cases of occupationally exposed workers with airway allergy to chlorhexidine. The role of chlorhexidine as an occupational allergen was confirmed by placebo-controlled specific inhalative challenge tests monitored by spirometry and analysis of induced sputum (influx of eosinophils after provocation has been observed). One of these patients presented with a systemic reaction with ordinary environment exposure. These findings are a reminder to clinicians of chlorhexidine's ability to cause various hypersensitivity reactions and the potential risk of this widely used antiseptic.