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

Polyhexamethylene biguanide hydrochloride (PHMB)-properties and application of an antiseptic agent. A narrative review

The prevention and management of ocular surface infections is still one of the great challenges for ophthalmologists. The spread of antimicrobial resistance makes it necessary to use antiseptic substances with a broad antimicrobial spectrum. Polyhexamethylene biguanide hydrochloride (Polyhexanide, PHMB) is a broad-spectrum antiseptic with excellent tolerance and a low-risk profile. Its physicochemical action on the phospholipid membrane and DNA replication or repair mechanism, prevents or impedes the development of resistant bacterial strains. PHMB revealed its effective against numerous organisms like viruses, Gram-negative and Gram-positive bacteria, and fungi. Polyhexanide is commonly used as preservative in commercially available disinfecting solutions for contact lens care and in ophthalmic formulations at different concentrations ranging from 1 µg/ml to 50 µg/ml. The administration of 0.02% (200 µg/ml) PHMB is often the first-line therapy of Acanthamoeba keratitis. However, to date, only one close-out randomized controlled study tested the efficacy of 0.02% PHMB in Acanthamoeba keratitis and a phase III study is still ongoing. This paper reviews the antiseptic agent PHMB, focusing on biochemical mechanisms, safety profile and applications in ophthalmology.

Update on the role of antiseptics in the management of chronic wounds with critical colonisation and/or biofilm

Biofilms play a major role in delaying chronic wounds from healing. A wound infiltrated with biofilm, or "critically colonised" wound, may become clinically infected if the number of microbes exceeds a critical level. Chronic wound biofilms represent a significant treatment challenge by demonstrating recalcitrance towards antimicrobial agents. However, a "window of opportunity" may exist after wound debridement when biofilms are more susceptible to topical antiseptics. Here, we discuss the role of antiseptics in the management of chronic wounds and biofilm, focusing on povidone-iodine (PVP-I) in comparison with two commonly used antiseptics: polyhexanide (PHMB) and silver. This article is based on the literature reviewed during a focus group meeting on antiseptics in wound care and biofilm management, and on a PubMed search conducted in March 2020. Compared with PHMB and silver, PVP-I has a broader spectrum of antimicrobial activity, potent antibiofilm efficacy, no acquired bacterial resistance or cross-resistance, low cytotoxicity, good tolerability, and an ability to promote wound healing. PVP-I represents a viable therapeutic option in wound care and biofilm management, with the potential to treat biofilm-infiltrated, critically colonised wounds. We propose a practical algorithm to guide the management of chronic, non-healing wounds due to critical colonisation or biofilm, using PVP-I.

In Vitro Efficacy of Bacterial Cellulose Dressings Chemisorbed with Antiseptics against Biofilm Formed by Pathogens Isolated from Chronic Wounds

Local administration of antiseptics is required to prevent and fight against biofilm-based infections of chronic wounds. One of the methods used for delivering antiseptics to infected wounds is the application of dressings chemisorbed with antimicrobials. Dressings made of bacterial cellulose (BC) display several features, making them suitable for such a purpose. This work aimed to compare the activity of commonly used antiseptic molecules: octenidine, polyhexanide, povidone-iodine, chlorhexidine, ethacridine lactate, and hypochlorous solutions and to evaluate their usefulness as active substances of BC dressings against 48 bacterial strains (8 species) and 6 yeast strains (1 species). A silver dressing was applied as a control material of proven antimicrobial activity. The methodology applied included the assessment of minimal inhibitory concentrations (MIC) and minimal biofilm eradication concentration (MBEC), the modified disc-diffusion method, and the modified antibiofilm dressing activity measurement (A.D.A.M.) method. While in 96-well plate-based methods (MIC and MBEC assessment), the highest antimicrobial activity was recorded for chlorhexidine, in the modified disc-diffusion method and in the modified A.D.A.M test, povidone-iodine performed the best. In an in vitro setting simulating chronic wound conditions, BC dressings chemisorbed with polyhexanide, octenidine, or povidone-iodine displayed a similar or even higher antibiofilm activity than the control dressing containing silver molecules. If translated into clinical conditions, the obtained results suggest high applicability of BC dressings chemisorbed with antiseptics to eradicate biofilm from chronic wounds.

Dermatologic reactions to disinfectant use during the COVID-19 pandemic

Infection preventive practice of using disinfectants against SARS-CoV-2 has become the new normal due to the COVID-19 pandemic. Although disinfectants may not be applied directly to the human body, it remains at high risk of exposure including close skin contact on disinfected surfaces or during handling. This dermal contact, on a regular basis, can induce hazardous skin reactions like irritation, inflammation, and burning in severe conditions. Disinfectants are germicide chemicals that can penetrate the skin and create skin reactions that are usually regarded as irritant and allergic contact dermatitis. More importantly, disinfectants can react with skin components (proteins and lipids) to facilitate their skin penetration and disrupt the skin barrier function. Whereas the antimicrobial actions of disinfectants are well understood, much less is known regarding their dermatologic reactions, including but not limited to irritation and hypersensitivity. We reviewed the skin reactions created by those disinfectants against SARS-CoV-2 approved by the European Chemical Agency and the US Environmental Protection Agency.

IgE-mediated chlorhexidine allergy-Cross-reactivity with other biguanide disinfectants

BACKGROUND

Chlorhexidine (CHX) is a widely utilized disinfectant that can cause IgE-mediated urticaria/anaphylaxis. The cross-reactivity of patients with IgE-mediated CHX allergy with other disinfectants, which share structural similarities with CHX like polyhexanide (polyhexamethylene biguanide; PHMB), alexidine (ALX), or octenidine (OCT), is unknown.

METHODS

Forty-four patients with anaphylaxis or urticaria upon CHX exposure and positive skin prick test (SPT) and/or positive CHX ImmunoCAP test (Phadia TFS, Uppsala, Sweden) were recruited. IgE to the biguanide and/or hexamethylene structure was investigated with PHMB ImmunoCAP (n = 32) and by basophil activation tests (BAT) with CHX and ALX (n = 37). Inhibition tests of CHX and PHMB ImmunoCAPs by CHX, ALX, PHMB, and OCT were performed.

RESULTS

IgE reactivity to PHMB as surrogate marker for biguanide/hexamethylene reactivity was detected in 5/32 sera. Seven of 37 patients showed a positive BAT with ALX, but only under optimized conditions. Binding to CHX ImmunoCAP was inhibited by ALX in 1/32 sera, and binding to PHMB was blocked by ALX (1/5) and by OCT in another (1/5). In SPT, 9/10 patients were positive for CHX and 3 of them with ALX (only at highest concentration at 5 mg/mL). A further patient reacted primarily with OCT and showed IgE cross-reactivity with CHX, ALX, and PHMB.

CONCLUSION

The IgE response to CHX seems polyclonal. The chloroguanide ending of CHX is the main epitope for the IgE and is suitable as screening assay to detect CHX reactivity. IgE-reactivities with the biguanide or hexamethylene components of other disinfectants (ALX, PHMB) can be detected by SPT, PHMB ImmunoCAP, and ALX-BAT in 15%-33% of CHX-allergic patients.

Contact allergy to polyhexamethylene biguanide (polyaminopropyl biguanide)

Background

Polyaminopropyl biguanide (INCI name) and polyhexamethylene biguanide (PHMB) are polymeric biguanides. PHMB is a broad‐spectrum antimicrobial substance used as a preservative in many products. Due to our limited knowledge on PHMB contact allergy frequency and the fact that cases of allergic contact dermatitis to PHMB might be missed, we have included PHMB as a screening allergen since 2016.

Objective

To report the prevalence of positive patch test reactions to PHMB as a screening allergen in patients with suspected allergic contact dermatitis.

Methods

A retrospective analysis of 1760 patch tested patients from July 2016 to December 2018 was performed. Polyaminopropyl biguanide 2.0% aqua was included in the extended Malmö baseline series during the study period.

Results

Of all patients, 1204 (68.4%) were female. Positive patch test reactions were reported in 19 patients (1.1%). The most common sites of lesions were face, head, and neck (52.6%). There was a significant correlation between concomitant reactions to PHMB and other cosmetic‐related allergens.

Conclusion

The prevalence of positive reactions to PHMB was higher than that previously reported. Patch testing with PHMB should be performed in patients with dermatitis who have lesions on the face, head, and neck.

Safety Assessment of Polyaminopropyl Biguanide (Polyhexamethylene Biguanide Hydrochloride) as Used in Cosmetics

The Expert Panel for Cosmetic Ingredient Safety (Panel) reviewed the safety of Polyaminopropyl Biguanide (polyhexamethylene biguanide hydrochloride), which functions as a preservative in cosmetic products. The Panel reviewed relevant data relating to the safety of this ingredient and concluded that Polyaminopropyl Biguanide is safe in cosmetics in the present practices of use and concentration described in the safety assessment, when formulated to be nonirritating and nonsensitizing, which may be based on a quantitative risk assessment or other accepted methodologies. The Panel also concluded that the data are insufficient to determine the safety of Polyaminopropyl Biguanide in products that may be incidentally inhaled.