Chlorhexidine-induced anaphylaxis in surgical patients: a review of the literature

Immediate allergies to chlorhexidine: A series of pediatric cases from the French pharmacovigilance database: Immediate allergies to chlorhexidine: series of pediatric cases from the French pharmacovigilance database

BACKGROUND

Immediate allergic reactions to chlorhexidine have been clearly identified in numerous countries, generating governmental warnings worldwide.

OBJECTIVES

The aim of our study was to characterize (i) these allergies, which are less reported in pediatric populations, and (ii) the patient-at-risk profile so as to suggest preventive measures.

METHODS

In association with the allergy department and the regional pharmacovigilance center in Rennes University Hospital, France, a multicenter retrospective, descriptive, and observational study was conducted using data from the national pharmacovigilance database for the period of January 1, 2010 to June 30, 2020. Immediate allergies to chlorhexidine cases based on a clinical history compatible with an immunoglobulin E (IgE)-mediated reaction, along with positive allergic testing, were analyzed.

RESULTS

Of the 478 cases identified, 17 pediatric cases of immediate allergic reaction to chlorhexidine (13 cases of grades II-IV anaphylaxis) were retained for the analysis. For 58.8 % of these cases, a history of a previous more moderate reaction to the substance was identified. The reactions occurred most frequently in cases of domestic misuse (88.2 %, n = 15/17) of chlorhexidine to dress a wound. Recurrence was reported for two cases, later leading to severe reactions at each new exposure to the allergen, suggesting an aggravation mechanism.

CONCLUSION

The number of pediatric cases of immediate allergies to chlorhexidine has possibly been underestimated on account of insufficient knowledge of the allergy and in view of its common usage. Information on the method of caring for wounds among children and on the risk of allergic sensitization as well as exploring any unusual reaction to chlorhexidine application could reduce the number of allergic reactions.

Life-threatening chlorhexidine anaphylaxis caused by skin preparation before chlorhexidine-free central venous catheter insertion: a case report and literature review

Chlorhexidine is a common cause of perioperative anaphylaxis, and global regulatory authorities have issued warnings about anaphylaxis due to chlorhexidine-containing central venous catheters (CVC) and its mucosal absorption. We present a case of life-threatening anaphylaxis after CVC insertion caused by chlorhexidine used for skin preparation. The onset of anaphylaxis was rapid and very severe, resulting in pulseless electrical activity. The patient was successfully resuscitated by emergency veno-arterial extracorporeal membrane oxygenation (VA-ECMO). Our case suggests that even skin preparation before chlorhexidine-free CVC insertion can cause life-threatening anaphylaxis. We reviewed the literature on chlorhexidine anaphylaxis cases and categorized all potential routes of chlorhexidine exposure to assess the risk following skin preparation. Our results showed that skin preparation before CVC insertion was the third most common cause of chlorhexidine anaphylaxis after transurethral exposure and chlorhexidine-containing CVCs. However, skin preparation with chlorhexidine before CVC insertion was sometimes overlooked as a cause of chlorhexidine anaphylaxis, and its risk might be underestimated. Further, no previous reports have described life-threatening anaphylaxis solely due to chlorhexidine skin preparation before CVC insertion. CVC insertion might cause the chlorhexidine used for skin preparation to reach the vascular system and should be recognized as a potential cause of life-threatening chlorhexidine anaphylaxis.

Immediate Hypersensitivity to Chlorhexidine: Experience from an Allergy Center in China

BACKGROUND

Chlorhexidine generally has a good safety profile. However, allergic reactions are reported with increasing frequency. In China, it is rarely reported, and its characteristics are unknown. The purpose of this study was to summarize the experience of a Chinese allergy center with chlorhexidine allergy.

METHODS

The authors retrospectively reviewed all patients who underwent chlorhexidine allergy testing in the Allergy Center of West China Hospital, Sichuan University (Chengdu, China), in the period February 2018 to May 2022 (n = 43 patients) and included the patients diagnosed with chlorhexidine allergy for analysis.

RESULTS

Ten patients who were diagnosed by skin prick and serum-specific immunoglobulin E tests were included. They experienced a total of 30 allergic reactions to chlorhexidine (mean ± SD, 3.0 ± 1.3). Five patients experienced six allergic reactions (6 of 30, 20%) during general or local anesthesia, and they may have been exposed to chlorhexidine via different routes. Only one allergic reaction (1 of 30, 3%) was recorded with exposure via a mouthwash. The other 23 allergic reactions (23 of 30, 77%) were caused via a skin disinfectant; the route of exposure was IV cannulation in 22 allergic reactions (22 of 23, 96%) and broken skin in one allergic reaction (1 of 23, 4%). The symptoms included a quick onset and great severity. Two patients (2 of 10, 20%) had been accidentally re-exposed to chlorhexidine after diagnosis.

CONCLUSIONS

This study conducted in China showed that the majority of reactions to chlorhexidine were attributed to skin disinfectants, and IV cannulation was the most common exposure route; in general, however, chlorhexidine allergy was easily overlooked. The potential allergenicity of chlorhexidine used for skin preparation before IV cannulation or should be considered in patients who develop allergic reactions perioperatively.

EDITOR’S PERSPECTIVE

Synergistic Effects of Silver Carboxylate and Chlorhexidine Gluconate for Wound Care and Prevention of Surgical Site Inflections by Cutibacterium acnes and Methicillin-Resistant Staphylococcus aureus

Background: This study presents the effectiveness of a combined silver carboxylate (AgCar) and chlorohexidine gluconate (AgCar:CHG) chemistry assessed against two commonly encountered nosocomial pathogens, Methicillin-resistant Staphylococcus aureus (MRSA) and Cutibacterium acnes, within the context of surgical antisepsis and wound care. Methods: Through an Institutional Review Board- and Institutional Animal Care and Use Committee (IACUC)-approved protocol, AgCar:CHG was applied to live Yucatan porcine skin and visualized by fast red and green staining to assess level of skin penetration. Dose response curves for Cutibacterium acnes and MRSA were generated to determine the optimal therapeutic ratio of AgCar to CHG. Coatings were applied to two different clinically available sutures and antimicrobial efficacy was evaluated at 24-hour intervals using Kirby-Bauer (KB) assays. Graphite furnace atomic absorption spectroscopy was used to measure AgCar elution from sutures over time. Results: Synergistic application of AgCar:CHG demonstrated deep pilosebaceous gland penetration on Yucatan pig skin. The therapeutic concentration range of AgCar was determined to be between 120 × -150 × and 30 × -60 × dopage for MRSA and Cutibacterium acnes, respectively. A 1:1 therapeutic ratio of AgCar to CHG was found to have 100% bactericidal activity against both pathogens. Sutures coated with AgCar:CHG showed sustained antimicrobial activity against MRSA and Cutibacterium acnes, and were significantly more efficacious than antimicrobial sutures over the three- to four-day period (p < 0.01). Conclusions: This AgCar:CHG chemistry demonstrates deep skin penetration, extended elution, and broad-spectrum antimicrobial activity compared with commercially available options. This chemistry shows promise as an additional tool for the prophylaxis of surgical site infections.

Gut-lung cross talk in COVID-19 pathology and fatality rate

Coronavirus disease 2019 (COVID-19) is the leading pandemic facing the world in 2019/2020; it is caused by a novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, which necessitates clear understanding of the infectious agent. The virus manifests aggressive behavior with severe clinical presentation and high mortality rate, especially among the elderly and patients living with chronic diseases. In the recent years, the role of gut microbiota, in health and disease, has been progressively studied and highlighted. It is through gut microbiota-organ bidirectional pathways, such as gut-brain axis, gut-liver axis, and gut-lung axis, that the role of gut microbiota in prompting lung disease, among other diseases, has been proposed and accepted. It is also known that respiratory viral infections, such as COVID-19, induce alterations in the gut microbiota, which can influence immunity. Based on the fact that gut microbiota diversity is decreased in old age and in patients with certain chronic diseases, which constitute two of the primary fatality groups in COVID-19 infections, it can be assumed that the gut microbiota may play a role in COVID-19 pathology and fatality rate. Improving gut microbiota diversity through personalized nutrition and supplementation with prebiotics/probiotics will mend the immunity of the body and hence could be one of the prophylactic strategies by which the impact of COVID-19 can be minimized in the elderly and immunocompromised patients. In this chapter, the role of dysbiosis in COVID-19 will be clarified and the possibility of using co-supplementation of personalized prebiotics/probiotics with current therapies will be discussed.

Review of Pre-Operative Skin Preparation Options Based on Surgical Site in Orthopedic Surgery

Background: Surgical site infections (SSIs) are a primary contributor to surgical morbidity and mortality, causing a substantial financial burden on the healthcare system. Specifically, Cutibacterium acnes contributes greatly to infections in the shoulder and spine regions. Prevention of infection is crucial to improve patient outcomes and reduce costs. This article reviews current surgical skin preparation solutions, the unique distribution of organisms at common orthopedic surgical sites, and recommends solutions based on surgical location. Methods: A search of electronic databases (PubMed, MEDLINE, and Embase) was conducted for relevant literature until December 2020. Sources were compiled based on title and abstract, then full texts were read for possible inclusion. This review summarizes the most recent publications in the field of SSIs and preparation solutions. Results: The mechanism and efficacy of alcohol-, iodine-, and chlorhexidine-based preparations were reviewed, along with experimental preparations. This article identifies common colonization patterns for the shoulder, elbow, hip, knee, spine, foot, and ankle, and discusses recommendations for preparations based on current evidence. Recommendations: For shoulder and elbow operations, we recommend ChloraPrep™ (CareFusion, BD, El Paso, TX), DuraPrep™ (3M Health Care, St. Paul, MN), or Betadine^® applied with 4 × 4 gauze sponge, three-day pre-operative benzyl peroxide, and application of 3% hydrogen peroxide before skin preparation. For the hip and knee, we recommend application of 2% chlorhexidine gluconate (CHG) cloth the night before and morning of surgery and either DuraPrep or iodine-alcohol skin prep prior to surgery. For spine surgeries, we recommended ChloraPrep. For foot and ankle, our recommendations are: ChloraPrep or DuraPrep, submersion of foot in 70% ethanol/10% isopropyl alcohol for five minutes prior to procedure, application with a bristled brush, and a second vigorous scrub with 4 × 4 soaked gauze. Conclusions: The current surgical skin preparations have both benefits and drawbacks. We recommend that orthopedic surgeons choose a skin preparation based on surgical site and prevalence of unique skin flora there.

Review of allergic reactions from use of chlorhexidine on medical products in clinical settings over 40 years: Risks and mitigations

Chlorhexidine is an antimicrobial agent widely used for infection prevention in medical settings. Nevertheless, allergic reactions ranging from mild to severe have been reported following its use. In this review, we analyzed all case reports published between the introduction of chlorhexidine and the end of 2019 for allergic responses associated with the use of medical devices and or other medical products containing chlorhexidine (CHX) to ascertain the prevalence of severe CHX allergic reactions and what practices might best mitigate those risks.In total, 77 publications containing 124 reported cases of allergic reactions were grouped into 3 product categories, catheters, semisolids, and fluid products. The country, type of reaction, route of sensitization, allergy confirmation, and intervention or mitigation was extracted for each case. Overall, 30 cases were associated with catheters, 46 cases were associated with semisolid products, and 48 cases were associated with the use of other medical products. Severe cases were managed with intravenous fluids, steroids, and epinephrine (adrenaline). None of the reported cases were fatal. The allergy risks can be mitigated by better warning and training clinicians and by recording and screening patient histories for CHX presensitization from prior exposure. For patients undergoing pre-use blood tests, IgE antibody screens can also be performed. Finally, as a precaution in the event a rare severe allergic reaction occurs, procedure carts and rooms can be prestocked with injectable epinephrine and other rapidly acting anti-inflammatory medications.

Can preprocedural mouthrinses reduce SARS-CoV-2 load in dental aerosols?

Dental professionals work closely with patients and present an increased risk of person-to-person transmission of SARS-CoV-2. Moreover, the use of ultrasonic scalers, air-water syringes, and slow and high-speed handpieces, which are common in the dental office, generate spatter and aerosol. The use of preprocedural mouthrinses has been proposed to reduce the viral load in saliva and oropharyngeal tissues, thus decreasing viral load in dental aerosol. Although some mouthrinses demonstrates an antiviral effect, there is limited evidence about the clinical efficacy of any mouthrinse in the reduction of SARS-CoV-2 in the dental aerosol. We hypothesized that mouthrinses may reduce SARS-CoV-2 viral load in the oropharynx and its fluids reducing viral load in dental aerosol. The potential use of mouthrinses is discussed, along with proposal of in vitro and clinical studies, in order to evaluate this hypothesis. If this hypothesis holds true, dental professionals and patients may benefit from the routine use of preprocedural mouthrinses.

Disinfection with single or double usage of new antiseptic olanexidine gluconate in general surgery: a randomized study

PURPOSE

Olanexidine gluconate is a newly developed solution for skin disinfection that was recently approved in Japan. We aimed to compare single and double application of the solution in preventing surgical site infection (SSI) in patients undergoing general surgery.

METHODS

This randomized study was conducted at the Tottori University Hospital. Patients scheduled to undergo gastrointestinal or hernia surgery were randomly assigned to one of two groups using either one or two Olanedine applicators for skin disinfection. The primary endpoint was the difference in SSI incidence between the two groups. The secondary endpoint was all adverse events related to olanexidine gluconate.

RESULTS

A total of 393 patients qualified for the study protocol: 193 received a single application, and 200 received a double application of Olanedine. SSI occurred in 10 patients (2.5%) overall; nine were superficial incisional SSIs, and one patient had a deep incisional SSI. Of the 10 patients who developed SSI, six (3.1%) were in the group receiving a single application, and four (2.0%) were in the group receiving a double application; there was no statistically significant difference between the two groups (P = 0.537). Allergic reactions or skin disorders related to olanexidine gluconate were not observed.

CONCLUSION

There was no difference in the SSI incidence between the use of one or two Olanedine applicators for skin preparation in elective general surgery. Therefore, a single application of Olanedine is sufficient and is recommended for general surgery as a standard disinfection precaution.

TRIAL REGISTRATION NUMBER

UMIN000027319; 5/12/2017.

Anaphylaxis related to disinfection with chlorhexidine in a teenager treated for cancer

INTRODUCTION

Literature shows upcoming allergy to chlorhexidine due to the widespread use of the disinfectant within and outside surgical settings. Only a few case reports have been published regarding the use of topical chlorhexidine disinfectant outside surgery and only a minority of these within the pediatric population.

CASE REPORT

We present a case-report of a teenager, treated for acute lymphoblastic leukemia who developed an anaphylactic shock after repeated chlorhexidine use for skin disinfection at the insertion of a central venous catheter during his chemotherapy treatment. Preceding minor symptoms such as local swelling and pruritus were not recognized as possible allergy to chlorhexidine.Management and outcome: He was treated with two doses of intramuscular adrenaline and transferred to the pediatric intensive care unit where he fully recovered. Specific IgE testing was positive for chlorhexidine. A total avoidance of chlorhexidine was instructed.

DISCUSSION

A similar case was published regarding an anaphylaxis after use of chlorhexidine disinfectant for a dialysis catheter. Almost all other case reports of anaphylactic shock were found within surgical settings or after insertion of an impregnated central venous catheter/urine catheter. We suggest that some of the disinfectant might have been flushed in the catheter and then caused an anaphylactic reaction. The link between symptoms and chlorhexidine was not made until an anaphylactic reaction occurred. Literature data show that chlorhexidine often causes mild preceding symptoms before an anaphylaxis occurs. So let awareness arise around this 'hidden allergen' of which warning reactions often are being missed.

Chlorhexidine Allergy: Current Challenges and Future Prospects

Chlorhexidine is a synthetic bisbiguanide antiseptic and was introduced in healthcare use in 1954. Allergy to chlorhexidine has been increasingly reported particularly in the perioperative and medical procedural settings. The hypersensitivity reactions range from mild cutaneous reactions to anaphylaxis or death. There are many products and medical devices containing chlorhexidine that sometimes lack standardized labeling. With the various routes of chlorhexidine exposure, accidental or recurrent reactions in chlorhexidine-allergic patients have been reported. Therefore, we aim to review the most recent evidence in clinical manifestations, diagnostic methods, management, and preventive measures with a focus on the unique features of chlorhexidine allergy.

The potential for developing new antimicrobial resistance from the use of medical devices containing chlorhexidine, minocycline, rifampicin and their combinations: a systematic review

Background

Catheter infections remain one of the most persistent adverse events causing significant morbidity, economic impact and mortality. Several strategies have been proposed to reduce these infections including the use of catheters embedded with antibiotics and/or antiseptics. One reoccurring challenge is the fear that antimicrobial medical devices will induce resistance. The aim of this systematic review is to evaluate the evidence for induced antimicrobial resistance caused by exposure to antimicrobial medical devices.

Methods

Four electronic databases [MEDLINE, Embase, Cumulative Index to Nursing and Allied Health Literature (CINAHL) and Scopus] were screened for studies published between 1983 and 2019 regarding assessment of microbial resistance with use of medical devices containing chlorhexidine, minocycline, rifampicin or combinations thereof. Development of new resistance, selection for tolerant organisms and 'no change in resistance' were assessed.

Results

Forty-four publications, grouped by study type and stratified by drug assessed, were included for analyses. The majority of studies found no change in resistance after exposure to antimicrobial medical devices (13 in vitro, 2 in vivo, 20 clinical). Development of new resistance was commonly reported with the use of rifampicin as a single agent and only reported in one study assessing the minocycline/rifampicin combination (M/R); however, the increase in MIC was well below clinical relevance.

Conclusions

Emergence of new resistance to combinations of M/R, minocycline/rifampicin/chlorhexidine (M/R/CH) and chlorhexidine/silver sulfadiazine (CHXSS) was rare. No clinical trials confirmed its occurrence and some refuted it. The risk of development of new resistance to these antimicrobial combinations appears more fear-based than substantiated by clinical and experimental evidence but warrants continued surveillance.

Olanexidine gluconate versus povidone-iodine for preventing surgical-site infection in orthopaedic surgery: A retrospective study

BACKGROUND

Olanexidine gluconate (OLG) is a newly developed skin antiseptic, which is effective against a broad range of bacteria, including methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus. The purpose of this study was to evaluate the bactericidal efficacy and safety of OLG in orthopaedic surgery.

METHODS

This retrospective study included a total of 1103 patients who underwent clean orthopaedic surgery. They were divided into two groups: 556 patients who were treated with OLG (OLG group), and 547 patients who were treated with povidone-iodine (PVP-I) (PVP-I group). The efficacy and the safety outcomes were measured as the rate of surgical-site infection (SSI) within 30 days after surgery and the rate of adverse skin reaction, respectively.

RESULTS

There was no significant difference between the OLG group and PVP-I group (1.80% vs. 2.38%; p = 0.50) based on the overall rate of SSI. Also, there was no significant difference in both superficial incisional infections (1.08% vs. 2.01%; p = 0.21) and deep incisional infections (0.72% vs. 0.37%; p = 0.35). The overall rate of adverse skin reaction was significantly higher in the OLG group than in the PVP-I group (2.16% vs. 0.73%; p = 0.047).

CONCLUSIONS

This retrospective study demonstrated that OLG has an efficacy similar to PVP-I in preventing SSI in clean orthopaedic surgery. However, adverse skin reactions at the application site of OLG requires more attention.

Efficacy and safety of a novel antimicrobial preoperative skin preparation

OBJECTIVE

Alternatives to skin preparation with conventional preoperative antiseptics are required because of adverse reactions and the potential emergence of resistance. Here, we present 2 phase 2 studies of ZuraGard (ZG), a novel formulation of isopropyl alcohol and functional excipients developed for preoperative skin antisepsis.

METHODS

Microbial skin flora on abdominal and inguinal sites in healthy volunteers were quantitatively assessed following application of ZG versus a negative control (ZV) and a chlorhexidine/alcohol preparation, Chloraprep (CP). In trial 1, ZG administered for both recommended and abbreviated application times was compared with CP and ZV via bacterial reductions at 10 minutes, and 6 hours, 12 hours, and 24 hours following application. In trial 2, the 10-minute postapplication responder rates (RRs) for ZG, participants with abdominal ≥2 log10 per cm2, and inguinal ≥3 log10 per cm2 reductions in colony-forming units (CFU) were compared to RRs of participants treated with CP.

RESULTS

In trial 1, ZG at the recommended application time reduced mean bacterial counts by ~3.18 log10 CFU/cm2 and ~2.98 log10 CFU/cm2 at abdominal and inguinal sites, respectively. Qualitatively similar reductions were observed for the abbreviated ZG application time and all CP applications. Application of ZV was ineffective. In trial 2, 10-minute RRs for ZG and CP exceeded 90% at abdominal sites. At inguinal sites, RRs were 83.3% for ZG and 86.7% for CP. No skin irritation or other adverse events were observed.

CONCLUSIONS

ZG matched CP efficacy under these experimental conditions with immediate and persistent microbial reductions, including abbreviated application times. Further clinical studies of this novel preoperative antiseptic are merited.

Chlorhexidine: a hidden life-threatening allergen

Chlorhexidine is a commonly used antiseptic and disinfectant in the health-care setting. Anaphylaxis to chlorhexidine is a rare but potentially life-threatening complication. Epidemiologic data suggest that the cases of chlorhexidine allergy appears to be increasing. In this article we report a life-threatening anaphylactic shock with cardiorespiratory arrest, during urethral catheterization due to chlorhexidine. The authors also performed a literature review of PubMed library of anaphylactic cases reports due to this antiseptic between 2014 and 2018, demonstrating the increase in the number of cases occurring worldwide and the importance of detailed anamnesis and appropriate diagnostic workup of allergic reactions to disinfectants.

Health care worker sensitivity to chlorhexidine-based hand hygiene solutions: A cross-sectional survey

BACKGROUND

Health service hand hygiene programs have seen widespread use of chlorhexidine solutions. Reports of both immediate and delayed hypersensitivity to chlorhexidine are increasing among health care workers. This study examined the prevalence of self-reported symptoms of sensitivity to chlorhexidine solutions among health care workers.

METHODS

This study was a cross-sectional online anonymous survey of all workers at a single health service.

RESULTS

Of the 1,050 completed responses, 76.3% were female, 35.3% were nurses and midwives, 28% were medical staff, and 8.7% were working in nonclinical areas. Over 95% used chlorhexidine-based hand hygiene products in their workplace. Nurses and midwives most frequently reported asthma (13.7%), contact dermatitis (27.8%), and previous testing for allergy to chlorhexidine (4.9%). There was a correlation between both the presence of atopy, eczema, or dermatitis and the self-reporting of dry skin, eczema, or dermatitis attributed to chlorhexidine use.

DISCUSSION

Occupational chlorhexidine allergy is an important risk to health care workers. Self-reported symptoms of sensitivity to chlorhexidine solutions revealed high reported use and presence of skin symptoms among health care workers.

CONCLUSIONS

Screening programs need to identify nurses who develop chlorhexidine sensitivity due to occupational exposure. Strategies to mitigate risk should provide alternatives for those with sensitization.

Chlorhexidine allergy in the perioperative setting: a narrative review

Chlorhexidine is an antiseptic with a broad spectrum of activity and a persistent effect on skin. Consequently, it has become an ubiquitous antiseptic in healthcare and the community. As use has become widespread, increasing numbers of cases of allergy have been reported in the literature, including cases of anaphylaxis to chlorhexidine gels used on mucous membranes, chlorhexidine-impregnated devices such as central venous catheters, chlorhexidine preparations used on wounds and broken skin, and cases after dental procedures. Numerous governmental warnings have been issued over recent decades to warn of the risk of allergy to chlorhexidine on mucosal surfaces or in medical devices. Whilst the number of published cases likely underestimates the true prevalence of reactions, we retrospectively surveyed clinics with experience in investigating perioperative chlorhexidine allergy. Despite differences in investigation practice before the survey took place, 13 clinics responded which together had diagnosed 252 cases of anaphylaxis to chlorhexidine, and cases of delayed allergy. In eight of 13 clinics, chlorhexidine was within the top four most commonly diagnosed causes of perioperative anaphylaxis. Despite this, the incidence of anaphylaxis to chlorhexidine is low given that patients are very commonly exposed. Sensitisation of healthcare workers can occur, but is uncommon. Before exposing patients to this antiseptic, consideration of the potential risk vs benefit should be undertaken, particularly for higher risk exposures, such as mucosal exposure or i.v. exposure via impregnated lines. Difficulties exist in protecting patients with known allergies from re-exposure to chlorhexidine, which would be improved with uniform labelling and chlorhexidine product registers.

Chlorhexidine Allergy: On the Rise and Often Overlooked

PURPOSE OF REVIEW

In recent years, the risk of allergy to chlorhexidine is increasingly recognised. In this review, we discuss why the allergy is so easily overlooked and point out several preventative initiatives that can minimise the risk of both chlorhexidine sensitisation and allergy development and accidental re-exposure in patients with chlorhexidine allergy. Testing for chlorhexidine allergy is also discussed.

RECENT FINDINGS

Numerous reports have been published from many different specialties. Symptoms range from mild skin symptoms to life-threatening anaphylaxis. Testing for chlorhexidine allergy is based on skin testing and in vitro testing. Recently, it was found that both skin prick testing and specific IgE have high sensitivities and specificities. This review gives an overview of chlorhexidine allergy with a special focus on preventative initiatives and testing.

Comparative epidemiology of suspected perioperative hypersensitivity reactions

Suspected perioperative hypersensitivity reactions are rare but contribute significantly to the morbidity and mortality of surgical procedures. Recent publications have highlighted the differences between countries concerning the respective risk of different drugs, and changes in patterns of causal agents and the emergence of new allergens. This review summarises recent information on the epidemiology of perioperative hypersensitivity reactions, with specific consideration of differences between geographic areas for the most frequently involved offending agents.

Chlorhexidine wipes: Time to stop and think about allergy

Summary

We report three precautionary cases of perioperative anaphylaxis to chlorhexidine isopropyl alcohol antiseptic wipes (CAW). In two cases, the patients were inadvertently re-exposed to CAW despite known chlorhexidine hypersensitivity. Chlorhexidine has been described as ‘the hidden allergen’. As a result, patients may suffer multiple reactions before chlorhexidine is confirmed as the cause. Healthcare workers may not recognize that products they use for common clinical steps contain chlorhexidine. These cases highlight the need for constant vigilance to facilitate the safe management of patients with a history of chlorhexidine anaphylaxis.

Can probiotics be an alternative to chlorhexidine for oral care in the mechanically ventilated patient? A multicentre, prospective, randomised controlled open trial

Background

Pathogenic enteric bacteria aspirated from the oropharynx are the main cause of ventilator-associated pneumonia (VAP). Using chlorhexidine (CHX) orally or selective decontamination has been shown to reduce VAP. In a pilot study we found that oral care with the probiotic bacterium Lactobacillus plantarum 299 (Lp299) was as effective as CHX in reducing enteric bacteria in the oropharynx. To confirm those results, in this expanded study with an identical protocol we increased the number of patients and participating centres.

Methods

One hundred and fifty critically ill patients on mechanical ventilation were randomised to oral care with either standard 0.1% CHX solution (control group) or a procedure comprising final application of an emulsion of Lp299. Samples for microbiological analyses were taken from the oropharynx and trachea at inclusion and subsequently at defined intervals.

Student’s t test was used for comparisons of parameters recorded daily and Fisher’s exact test was used to compare the results of microbiological cultures.

Results

Potentially pathogenic enteric bacteria not present at inclusion were identified in oropharyngeal samples from 29 patients in the CHX group and in 31 samples in the probiotic group. Considering cultures of tracheal secretions, enteric bacteria were found in 17 and 19 samples, respectively. Risk ratios show a difference in favour of the Lp group for fungi in oropharyngeal cultures. VAP was diagnosed in seven patients in the Lp group and in 10 patients among the controls.

Conclusions

In this multicentre study, we could not demonstrate any difference between Lp299 and CHX used in oral care procedures regarding their impact on colonisation with emerging potentially pathogenic enteric bacteria in the oropharynx and trachea.

Trial registration

ClinicalTrials.gov, NCT01105819. Registered on 9 April 2010.

First part: Current Controlled Trials, ISRCTN00472141. Registered on 22 November 2007 (published Critical Care 2008, 12:R136).

Chlorhexidine-related anaphylaxis in urological practice

Introduction:

There have been numerous case reports highlighting the risk of anaphylactic reactions when using chlorhexidine-containing urethral gels. However, there is no evidence that the inclusion of chlorhexidine in urethral gels reduces the risk of catheter associated urinary tract infection.

Methods:

Pubmed and Medline were searched for the keywords anaphylaxis (and) chlorhexidine. Case reports were reviewed and information regarding year, patient demographics, country, chlorhexidine administration route, signs, symptoms encountered and the presence of subsequent allergy testing were analysed.

Results:

In terms of clinical features, 89% (32/36) of patients were noted to have skin changes recorded as either urticaria, flushing, rash, erythema or wheals. Respiratory changes were recorded in 67% (24/36), which included those described as bronchospasm, chest tightness, wheeze or cough. Hypotension was documented in 92% of reports (33/36) while hypoxia was recorded in half of the reports (18/36) and a quarter (8/36) had periorbital angioedema or documented oral or tongue swelling. Only four out of 36 patients required formal cardiopulmonary resuscitation and no patients died.

Conclusion:

Chlorhexidine-related anaphylaxis is a relatively frequently reported entity. Despite this, there appears to be no compelling evidence that chlorhexidine mitigates the risk of catheter-associated urinary tract infection.

Level of evidence:

Level 4 evidence.

Antimicrobial Resistance to Agents Used for Staphylococcus aureus Decolonization: Is There a Reason for Concern?

PURPOSE OF REVIEW

Chlorhexidine gluconate (CHG) and mupirocin are increasingly used for Staphylococcus aureus decolonization to prevent healthcare-associated infections; however, increased use of these agents has led to concerns for growing resistance and reduced efficacy. In this review, we describe current understanding of reduced susceptibility to CHG and mupirocin in S. aureus and their potential clinical implications.

RECENT FINDINGS

While emergence of S. aureus tolerant or resistant to topical antimicrobial agents used for decolonization is well described, the clinical impact of reduced susceptibility is not clear. Important challenges are that standardized methods of resistance testing and interpretation are not established, and the risk for selection for co- or cross-resistance using universal, as opposed to targeted decolonization, is unclear. Evidence continues to support S. aureus decolonization in certain patient groups, although further studies are needed to determine the long-term impact of CHG and mupirocin resistance on efficacy. Strategies to mitigate further development of reduced susceptibility and the consequences of selection pressures through universal decolonization on resistance will benefit from further investigation.

Comparison of antibacterial activity of alexidine alone or as a final irrigant with sodium hypochlorite and chlorhexidine

Aims:

To compare the antibacterial activity of alexidine (ALX) alone or as a final irrigant in combination with sodium hypochlorite (NaOCl), with the most common canal irrigants, NaOCl and chlorhexidine (CHX).

Materials and methods:

Ninety-four root fragments from extracted human teeth were infected with Enterococcus faecalis for 24 h and then distributed into 4 groups of 20 fragments each. The NaOCl, CHX and ALX groups were immersed in 1 ml of 2.5% NaOCl, 2% CHX, and 1% ALX for 10 min, respectively. The samples of the NaOCl+ALX group were immersed in 1 ml of 2.5% NaOCl for 10 min followed by 1% ALX for 10 min. Bacteriological samples were taken, cultured, and the colony-forming units were counted.

Results:

There was no significant differences among the experimental groups (P>0.05) except for the comparisons CHX versus ALX and NaOCl+ALX versus ALX (P=0.004). ALX alone was the worst irrigant. CHX and NaOCl+ALX eradicated all bacteria. All experimental groups were significantly more effective than the control group immersed in saline (P<0.05).

Conclusions:

The antibacterial effect of ALX alone was inferior to 2% CHX and 2.5% NaOCl. However, the combination of NaOCl with ALX as a final irrigant eradicated the biofilms.

Antibiofilm and Anti-Inflammatory Activities of Houttuynia cordata Decoction for Oral Care

Dental biofilms that form in the oral cavity play a critical role in the pathogenesis of several infectious oral diseases, including dental caries, periodontal disease, and oral candidiasis. Houttuynia cordata (HC, Saururaceae) is a widely used traditional medicine, for both internal and external application. A decoction of dried HC leaves (dHC) has long been consumed as a health-promoting herbal tea in Japan. We have recently reported that a water solution of HC poultice ethanol extract (wHCP) exerts antimicrobial and antibiofilm effects against several important oral pathogens. It also exhibits anti-inflammatory effects on human keratinocytes. In our current study, we examined the effects of dHC on infectious oral pathogens and inflammation. Our results demonstrated that dHC exerts moderate antimicrobial effects against methicillin-resistant Staphylococcus aureus (MRSA) and other oral microorganisms. dHC also exhibited antibiofilm effects against MRSA, Fusobacterium nucleatum (involved in dental plaque formation), and Candida albicans and inhibitory effects on interleukin-8, CCL20, IP-10, and GROα productions by human oral keratinocytes stimulated by Porphyromonas gingivalis lipopolysaccharide (a cause of periodontal disease), without cytotoxic effects. This suggests that dHC exhibits multiple activities in microorganisms and host cells. dHC can be easily prepared and may be effective in preventing infectious oral diseases.

Life-threatening intraoperative anaphylaxis as a result of chlorhexidine present in Instillagel

A 70-year-old man with left lower limb critical ischaemia was admitted to our vascular unit for a femoral-popliteal bypass. He had experienced a skin reaction to chlorhexidine 6 months previously during an angioplasty procedure. After intubation, once in the operating theatre, the patient had a urinary catheter inserted using Instillagel. Around 30 min later the patient had a full-blown anaphylactic reaction that required aggressive medical management and the abandoning of surgery. Postoperative allergy testing confirmed that the suspected primary trigger for the anaphylaxis was indeed chlorhexidine, which was present in Instillagel. The patient was also found to have allergies to atracurium and teicoplanin, which had been given on induction. This case report highlights the importance of recognising that Instillagel contains chlorhexidine, and that indeed intraurethral use during routine urinary catheterisation can be a cause of life-threatening anaphylaxis.

Anaphylaxis after disinfection with 2% chlorhexidine wand applicator

A 54-year-old man with end-stage renal failure attended for dialysis. Within seconds of applying 2% w/v chlorhexidine (ChloraPrep 3 mL Wand Applicator) to the skin surrounding the insertion point of his dialysis catheter (Tesio catheter), he developed pruritus, urticaria, shortness of breath, hypotension and reduced responsiveness. Treatment for anaphylaxis was initiated with rapid improvement of his symptoms, and he made a full recovery. Allergy to chlorhexidine was confirmed with skin testing, and the patient was warned against all future exposure to chlorhexidine. Subsequent dialysis without chlorhexidine was uneventful.

Chlorhexidine allergy in four specialist allergy centres in the United Kingdom, 2009-13: clinical features and diagnostic tests

We describe an observational survey of diagnostic pathways in 104 patients attending four specialist allergy clinics in the United Kingdom following perioperative hypersensitivity reactions to chlorhexidine reactions. The majority were life-threatening. Men undergoing urological or cardiothoracic surgery predominated. Skin prick testing and specific immunoglobulin (sIg)E testing were the most common tests used for diagnosis. Fifty-three per cent of diagnoses were made on the basis of a single positive test. Where multiple tests were performed the sensitivity of intradermal, basophil activation and skin prick testing was 68% (50-86%), 50% (10-90%) and 35% (17-55%), respectively. Seven per cent were negative on screening tests initially, and 12 cases were only positive for a single test despite multiple testing. Intradermal tests appeared most sensitive in this context. Additional sensitization to other substances used perioperatively, particularly neuromuscular blocking agents (NMBA), was found in 28 patients, emphasizing the need to test for possible allergy to all drugs to which the patient was exposed even where chlorhexidine is positive.

Australian and New Zealand Anaesthetic Allergy Group/ Australian and New Zealand College of Anaesthetists Perioperative Anaphylaxis Management Guidelines

Anaphylaxis is an uncommon but important cause of serious morbidity and even mortality in the perioperative period. The Australian and New Zealand College of Anaesthetists (ANZCA) with the Australian and New Zealand Anaesthetic Allergy Group (ANZAAG) have developed clinical management guidelines that include six crisis management cards. The content of the guidelines and cards is based on published literature and other international guidelines for the management of anaesthesia-related and non–anaesthesia-related anaphylaxis. The evidence is summarised in the associated background paper (Perioperative Anaphylaxis Management Guidelines [2016] www.anzca.edu.au/resources/endorsed-guidelines and www.anzaag.com/Mgmt%20Resources.aspx ). These guidelines are intended to apply to anaphylaxis occurring only during the perioperative period. They are not intended to apply to anaphylaxis outside the setting of dedicated monitoring and management by an anaesthetist. In this paper guidelines will be presented along with a brief background to their development.