A Case of Severe Anaphylaxis to Polyhexanide: Cross-Reactivity between Biguanide Antiseptics.

We present the case of a 77-year-old female patient who suffered from severe anaphylaxis during wound care. Allergologic evaluation yielded specific IgE antibodies to chlorhexidine, but anaphylaxis to chlorhexidine was not congruent with the patient history and dermal provocation tests. However, skin prick tests provided evidence for a sensitization to polyhexanide that was further supported by the detection of specific IgE antibodies to polyhexanide, the results of basophil activation tests and IgE inhibition analysis. We presume cross-reactive IgE antibodies binding to both biguanide antiseptics and identified polyhexanide as the likely cause of the anaphylactic reaction. We recognize polyhexanide as an emerging allergen that has to be considered as a cause of anaphylaxis.