D3.275 - Anaphylaxis caused by polyhexanide

Polyhexanide is a polymer used as a disinfectant and antiseptic, belonging to the biguanide family, with documented in-vitro cross-reactivity with chlorhexidine.

We present the case of a 50-year-old patient who underwent multiple skin grafts and a left dorsal muscle-to-tibia transfer after an open fracture at age 16. Since then, he has performed daily wound care with antiseptics, including polyhexanide.

Minutes after treating the leg ulcer with polyhexanide gel and calcium alginate, started with localized pruritus at the wound site progressed to generalized pruritus, erythematous rash, facial and limb edema, dyspnea, and somnolence. He received medical care with intramuscular adrenaline, methylprednisolone, and dexchlorpheniramine, resolving symptoms within two hours. Previously the patient reported local swelling and rash when using wound dressing that contained polyhexanide.

The patient was referred to our Allergy Department, where patch test with True test, standard GEIDAC, methacrylate’s series, calcium alginate and dressing that contains silver sulfate were carried out. Skin prick test (SPT) were performed with polyhexanide gel and liquid, chlorhexidine, and suspected excipients (table 1). Our protocol included controlled topical application of polyhexanide gel, chlorhexidine on healthy skin and repeated open application test with silver sulfadiazine and nitrofurazone.

In vitro test included total IgE level of 65.2 IU/mL, specific IgE to chlorhexidine < 0.10 kU/L, and serum tryptase level of 7.35 μg/mL. 

SPT gave positive results in immediate reading to Polyhexanide gel and liquid. Both controlled topical application of polyhexanide and chlorhexidine were negative. Repeated open application with silver sulfadiazine and nitrofurazone was well tolerated.

Patch Test reading was performed according to the ESCD guidelines and showed positive results to Thimerosal (++) and gold sodium Thiosulfate (+) after 48 and 96 hours reading. 

Our patient experienced a Grade 2 systemic after polyhexanide gel use. SPT positive to polyhexanide suggest its implication as a causative agent.

While there is extensive literature on chlorhexidine-induced anaphylaxis, reports of polyhexanide related anaphylaxis are limited.

This case highlights the importance of polyhexanide as a potential allergen.Although clinical relevance of in-vitro cross reactivity between biguanides has not been yet established, our patient was advised to avoid its use.