IgE-mediated allergy to chlorhexidine

Management and treatment of perioperative hypersensitivity

PURPOSE OF REVIEW

Perioperative hypersensitivity reactions are rare but potentially catastrophic events. This review acts to summarize recent recommendations for both immediate and poststabilization management of suspected reactions, alongside practical advice for anaesthetists who may be faced with these events.

RECENT FINDINGS

Prompt treatment is essential but may be hampered by delay in recognition. This can occur because there are multiple differential diagnoses for the observed clinical signs as well as variations in clinical presentation. Resuscitation is dependent on the use of adrenaline and fluids. Adrenaline should be administered in small, titrated intravenous boluses. Low-dose infusions should be commenced early if the response to boluses is poor. Large volume fluid resuscitation may be required to maintain adequate circulating volume. Chest compressions are recommended when there is evidence of inadequate perfusion, rather than waiting until cardiac arrest is confirmed. Antihistamines and corticosteroids are no longer recommended in the immediate management phase. Once the patient has been stabilized, it is important to obtain serial tryptase concentrations to aid the subsequent clinic investigation. The decision to proceed or abandon surgery will be based on an individual risk-benefit analysis. All cases of suspected perioperative hypersensitivity, including fatal cases, must be referred for formal investigation.

SUMMARY

There have been recent updates to management guidelines in perioperative hypersensitivity. Treatment algorithms, treatment packs and referral packs can all help the anaesthetist manage these complex cases, aid the subsequent investigation and ensure patient safety in the future.

Perioperative hypersensitivity in children: A prospective multidisciplinary study

BACKGROUND

There are few studies of perioperative hypersensitivity reactions in children. The diagnosis of perioperative hypersensitivity reactions may be under estimated because it is difficult to recognize the reactions. Anaphylaxis may go unnoticed because of patient unconsciousness. Urticaria may be missed due to sterile drapes. The aim of this study was to prospectively evaluate perioperative hypersensitivity reactions.

METHODS

In this prospective study, patients with suspected perioperative hypersensitivity reactions aged 0-18 years who underwent surgery at the Department of Pediatric Surgery, Cerrahpasa Faculty of Medicine, between 2019 and 2021 were investigated. Suspected reactions in the perioperative period were graded according to the Ring and Messmer scale. Patients with suspected reactions were examined 4-6 weeks after the reaction. If necessary, specific IgE and basophil activation tests were performed. Reactions of grades III-IV were considered anaphylaxis. If one test modality was strongly positive and there was a relevant time point or repeated allergic reactions, or at least two test modalities were positive, hypersensitivity was confirmed. In all patients, serum tryptase levels were analyzed at the time of the reaction, 2 h after the reaction, and 4-6 weeks after the reaction as part of the allergic evaluation.

RESULTS

A total of 29 patients (8 female, 21 male) suspected of having an intraoperative reaction during the study were included in the analysis. Perioperative hypersensitivity reactions were noted in 1 patient. The incidence of perioperative hypersensitivity reactions was reported to be 0.03% (n = 1/2861). While anaphylaxis was confirmed in 1 patient, 5 patients were considered possible anaphylaxis cases.

CONCLUSION

Perioperative hypersensitivity reactions can be life-threatening and may recur with further administration. Collaboration between pediatric surgeons, anesthesiologists, and allergists can prevent further reactions. All suspected cases should be evaluated by an experienced allergist soon after the initial reaction.

Patch Testing to Chlorhexidine Digluconate, 1% Aqueous: North American Contact Dermatitis Group Experience, 2015-2020

Background: Chlorhexidine is an antiseptic that may cause allergic contact dermatitis. Objectives: To describe the epidemiology of chlorhexidine allergy and characterize positive patch test reactions. Methods: This retrospective study analyzed patients patch tested to chlorhexidine digluconate 1% aqueous by the North American Contact Dermatitis Group, 2015-2020. Results: Of 14,731 patients tested to chlorhexidine digluconate, 107 (0.7%) had an allergic reaction; of these, 56 (52.3%) reactions were currently clinically relevant. Most (59%) reactions were mild (+), followed by strong (++, 18.7%) and very strong (+++, 6.5%). Common primary dermatitis anatomic sites in chlorhexidine-positive patients were hands (26.4%), face (24.5%), and scattered/generalized distribution (17.9%). Compared with negative patients, chlorhexidine-positive patients were significantly more likely to have dermatitis involving the trunk (11.3% vs 5.1%; P = 0.0036). The most commonly identified source category was skin/health care products (n = 41, 38.3%). Only 11 (10.3%) chlorhexidine reactions were occupationally related; of these, 81.8% were in health care workers. Conclusions: Chlorhexidine digluconate allergy is uncommon, but often clinically relevant. Involvement of the hands, face, and scattered generalized patterns was frequent. Occupationally related reactions were found predominantly in health care workers.

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

A quarter of a century fundamental and translational research in perioperative hypersensitivity and anaphylaxis at the Antwerp university hospital, a Belgian Centre of Excellence of the World Allergy Organization

Perioperative hypersensitivity constitutes an important health issue, with potential dramatic consequences of diagnostic mistakes. However, safe and correct diagnosis is not always straightforward, mainly because of the application of incorrect nomenclature, absence of easy accessible in-vitro/ex-vivo tests and uncertainties associated with the non-irritating skin test concentrations. In this editorial we summarize the time line, seminal findings, and major realizations of 25 years of research on the mechanisms, diagnosis, and management of perioperative hypersensitivity.

Allergic and other adverse reactions to drugs used in anesthesia and surgery

The list of drugs patients may be exposed to during the perioperative and postoperative periods is potentially extensive. It includes induction agents, neuromuscular blocking drugs (NMBDs), opioids, antibiotics, sugammadex, colloids, local anesthetics, polypeptides, antifibrinolytic agents, heparin and related anticoagulants, blue dyes, chlorhexidine, and a range of other agents depending on several factors related to individual patients’ clinical condition and progress in the postoperative recovery period. To avoid poor or ultrarapid metabolizers to a particular drug (for example tramadol and codeine) or possible adverse drug reactions (ADRs), some drugs may need to be avoided during or after surgery. This will be the case for patients with a history of anaphylaxis or other adverse events/intolerances to a known drug. Other drugs may be ceased for a period before surgery, e.g., anticoagulants that increase the chance of bleeding; diuretics for patients with acute renal failure; antihypertensives relative to kidney injury after major vascular surgery; and serotonergic drugs that together with some opioids may rarely induce serotonin toxicity. Studies of germline variations shown by genotyping and phenotyping to identify a predisposition of genetic factors to ADRs offer an increasingly important approach to individualize drug therapy. Studies of associations of human leukocyte antigen (HLA) genes with some serious delayed immune-mediated reactions are ongoing and variations of drug-metabolizing cytochrome CYP450 enzymes, P-glycoprotein, and catechol-O -methyltransferase show promise for the assessment of ADRs and non-responses to drugs, particularly opioids and other analgesics. Surveys of ADRs from an increasing number of institutions often cover small numbers of patients, are retrospective in nature, fail to clearly identify culprit drugs, and do not adequately distinguish immune-mediated from non-immune-mediated anaphylactoid reactions. From the many surveys undertaken, the large list of agents identified during and after anesthesia and surgery are examined for their ADR involvement. Drugs are classified into those most often involved, (NMBD and antibiotics); drugs that are becoming more frequently implicated, namely antibiotics (particularly teicoplanin), and blue dyes; those becoming less frequently involved; and drugs more rarely involved in perioperative, and postoperative adverse reactions but still important and necessary to keep in mind for the occasional potential sensitive patient. Clinicians should be aware of the similarities between drug-induced true allergic type I IgE/FcεRI- and pseudoallergic MRGPRX2-mediated ADRs, the clinical features of each, and their distinguishing characteristics. Procedures for identifying MRGPRX2 agonists and diagnosing and distinguishing pseudoallergic from allergic reaction mechanisms are discussed.

In vitro evaluation of antibacterial nanomaterial-induced anaphylactoid reaction for indwelling catheters

Background

To prevent tunnel infection of indwelling catheters, impregnation with antiseptics or antibiotics is effective. However, 13 patients using chlorhexidine–silver sulfadiazine-impregnated catheters experienced serious anaphylactic shock in Japan. Thus, it is necessary to select a suitable evaluation method for allergic reactions and develop a novel antibacterial coating material that does not cause anaphylactic reaction.

Methods

Two types of highly dispersible and antibacterial nanoparticles—fluorine (F)-doped hydroxyapatite (HAp) and zinc (Zn)-doped HAp—were tested using of the system and compared with compound 48/80 (c48/80) as a histamine releaser and chlorhexidine gluconate (CHG) as an anaphylactic inducer.

Results

The histamine concentrations secreted from HMC-1 cells remained mostly the same even with the addition of F-HAp and Zn-HAp. On the contrary, the levels of the chemical mediators from the cells by the addition of F-HAp and Zn-HAp were significantly lower than those of only c48/80 and CHG without the addition of HAp.

Conclusions

The assay was a well-evaluated method for quantifying histamine concentrations released from HMC-1 cells. Our study induced HMC-1 cells accompanied with and without the nanomaterials; the potential of F-HAp and Zn-HAp to induce allergic reactions was found to be quite low. Therefore, the antibacterial nanomaterials are expected to hardly induce anaphylactoid reactions.

Intraoperative chlorhexidine-induced anaphylaxis suggesting an immunoglobulin-E-dependent mechanism indicated by basophil activation tests: two case reports

BACKGROUND

Although chlorhexidine allergy has been shown to be mediated by immunoglobulin (Ig) E, few reports investigated the mechanism of chlorhexidine-induced anaphylaxis using basophil activation tests (BATs).

CASE PRESENTATION

A 79-year-old man underwent cholecystectomy under general anesthesia. Anaphylaxis was diagnosed based on the clinical symptoms and high serum tryptase and histamine levels. Skin tests showed positive results only for chlorhexidine. Subsequently, BATs demonstrated that the causative agent was likely chlorhexidine. The inhibitory effect of wortmannin, an inhibitor of phosphoinositide 3-kinase, on basophil activation suggested an IgE-dependent mechanism underlying chlorhexidine-induced anaphylaxis. An 89-year-old man underwent inguinal hernioplasty under general anesthesia. Anaphylaxis was diagnosed based on the clinical symptoms and high serum tryptase and histamine levels. Skin tests and BATs with wortmannin were performed, showing similar results to case 1.

CONCLUSIONS

BATs suggested an IgE-dependent mechanism for chlorhexidine-induced anaphylaxis and might be useful for investigating the mechanisms underlying drug-induced anaphylaxis.

Continuous antimicrobial mechanism of dispersible hydroxyapatite nanoparticles doped with zinc ions for percutaneous device coatings

Percutaneous devices-indwelling catheters-related infections are serious clinical incidents. It is accordingly necessary to develop anti-infective coating materials suitable for the devices for long-term effectiveness. In our research group, highly dispersible and crystalline hydroxyapatite (HAp) nanoparticles doped with metallic or halogen ions possessing antibacterial activities have been developed. In this study, antibacterial, dispersible, and crystalline zinc (Zn)-doped hydroxyapatite [Zn(15)-HAp] nanoparticles substituted with 13.5% Zn content [Zn/(Zn + Ca) × 100] were prepared by a wet chemical method using an anti-sintering agent through calcination. Antibacterial activities of Zn(15)-HAp nanoparticles were evaluated using Escherichia coli (E. coli) and Staphylococcus aureus. The survival rates of the bacteria on Zn(15)-HAp nanoparticles were significantly lower than that on normal HAp (nHAp) coated surfaces, while no influences were observed on proliferation of L929 cells. Even after soaking Zn(15)-HAp nanoparticles in PBS for 2 weeks, the antibacterial activities against E. coli were maintained at a similar level to a 20 min soaking. The bacterial death was related to not only ion-exchange phenomenon between Zn and magnesium ions but also accumulation of reactive oxygen species (ROS) in the cells. Allergic-like reactions-anaphylactoid reactions-might not readily occur with Zn(15)-HAp nanoparticles because the amounts of histamine released from HMC-1 cells co-cultured with nanoparticles were not significantly different to that of nHAp, but were statistically much lower than that of chlorhexidine.

Work-related allergy and asthma associated with cleaning agents in health workers in Southern African tertiary hospitals

BACKGROUND

Health workers (HWs) are exposed to diverse cleaning agents in large hospitals. This study determined the prevalence of work-related symptoms, allergic sensitization, and lung function abnormalities in HWs of two tertiary hospitals in Southern Africa.

METHODS

A cross-sectional study of 699 HWs (South Africa: SAH, n = 346; Tanzania: TAH, n = 353) was conducted. Health outcomes were assessed using a standardized ECRHS questionnaire, immunological tests (specific IgE antibody to common aero-allergens and to occupational allergens: natural rubber latex [NRL]  Hev b5 and Hev b6.02, chlorhexidine, and ortho-phthalaldehyde [OPA]), spirometry [pre-and post- bronchodilator], methacholine challenge, and fractional exhaled nitric oxide (FeNO).

RESULTS

A large proportion of participants (78%) were women. Median age was 42 years, with 76% nurses, 12% cleaners, and 5% administrative workers. Current smoking was more common in SAHWs (12%) than TAHWs (1%). The overall prevalence of doctor-diagnosed asthma was 7%. Atopy was present in 43% of HWs, while 4% were sensitized to OPA, 2% to NRL, and 1% to chlorhexidine. Prevalence of work-related ocular-nasal symptoms (16%) was higher than skin (12%) and chest (7%) symptoms. TAHWs had significantly lower mean lung volumes, higher degrees of significant airflow obstruction and impaired lung function. The prevalence of bronchial hyperresponsiveness in SAHWs (14%) was high. Overall, 23% of HWs had abnormal FeNO; 6% having high (>50 ppb) levels. FeNO was positively associated with sensitization to occupational allergens, primarily OPA and NRL.

CONCLUSIONS

HWs from both hospitals had similar prevalence of work-related respiratory symptoms. Sensitization to OPA and NRL appears to be contributing to allergic airway inflammation in these HWs.

Should oral chlorhexidine remain in ventilator-associated pneumonia prevention bundles?

Ventilator-associated pneumonia (VAP) is related with high mortality, duration of mechanical ventilation and costs. Recent studies have questioned the safety and effectiveness of oral chlorhexidine to prevent VAP. We sought to verify whether the adverse effects of this substance outweigh its benefits. We searched several databases and selected studies that investigated the use of oral chlorhexidine and its impact on mortality. No association between oral chlorhexidine and lower VAP rates was found on meta-analyses of double-blind randomized trials, however significant increase in mortality was reported. It is speculated that chlorhexidine can cause damage to several organic sectors and cytotoxicity. Although it still can be beneficial in specific settings, robust evidence to recommend its routine application for all mechanically ventilated patients is lacking; therefore, given the possibility of harm, it would be better to follow the principle of non-maleficence until more studies becomes available.

Vaccine allergy: evidence to consider for COVID-19 vaccines

PURPOSE OF REVIEW

Whereas the COVID-19 pandemic has changed our lives worldwide, we hope that vaccination can combat the disease. We propose how to evaluate suspected severe allergic reactions to the vaccines so that as many as possible may be safely vaccinated.

RECENT FINDINGS

Rare cases of severe allergic reactions after COVID-19 vaccination have been observed, seemingly at a higher frequency than for other vaccines. Few excipients are likely to have caused these reactions. IgE-mediated reactions to polyethylene glycol (PEG) and its derivatives are the most suspected, albeit hitherto unproven, causes. We suggest to make a diagnosis based on skin tests with PEG and PEG derivatives and that these be considered in relation to the decisions required before the first and the second vaccine dose. A vaccine without these excipients is available, but published data about its side effects are limited.

SUMMARY

The underlying immunological mechanisms of the rare severe allergic reactions to the COVID-19 vaccines are poorly understood and need to be clarified. Identifying those who have an undiagnosed allergy to PEG and PEG derivatives is crucial before vaccination, and these substances are found in laxatives, cosmetics and in 30% of all our medications today.

Detection of drug-specific immunoglobulin E (IgE) and acute mediator release for the diagnosis of immediate drug hypersensitivity reactions

The diagnosis of a drug hypersensitivity reaction (DHR) is complex. The first step after taking the clinical history is to look for a sensitization to confirm or exclude the diagnosis and to identify the culprit drug. Skin tests are the primary means of detecting sensitization in DHR, but are associated with a risk for a severe reaction and may be contraindicated. In vitro tests offer the potential to support or confirm a diagnosis of DHR and influence medical decision making. For immediate-type DHR, a few validated assays for measurement of specific IgE (sIgE) are commercially available to a limited number of drugs. In addition, several home-made sIgE radioimmunoassays have been used in other studies. The sensitivity of the sIgE assay is drug-dependant and generally low (0-85%) for betalactams and reported heterogeneous for other drugs ranging from 26% for chlorhexidine and 44% for suxamethonium to 92% for chlorhexidine. However, as all these studies included patients, in whom DHR was confirmed only by skin tests and not by provocation, the results have to be interpreted carefully and may be unreliable. Determination of mediators during an acute phase of a reaction may indirectly support the diagnosis of a DHR by demonstrating mast cell and basophil mediator release. Negative in vitro tests do not exclude a DHR or imputability of a drug, but a positive result may support causality and eliminate the necessity for a drug provocation test. Unfortunately, evidence is limited with a lack of well-controlled studies in larger numbers of well-phenotyped patients, which results in susceptibility for bias and a need for future multicenter studies.

Optimizing investigation of suspected allergy to polyethylene glycols

BACKGROUND

Polyethylene glycols (PEGs) are polymers of varying molecular weight (MW) used widely as excipients in drugs and other products, including the mRNA vaccines against coronavirus disease 2019. Allergy to PEGs is rare. Skin testing and graded challenge carries a high risk of inducing systemic reactions.

OBJECTIVE

We evaluated skin prick test (SPT) results and in vitro reactivity over time to different MW PEGs and assessed cross-sensitization patterns in PEG allergy.

METHODS

Ten patients with previously diagnosed PEG allergy underwent SPT twice with PEGs 26 months apart. Lower MW (PEG 300, 3000, 6000) were tested, followed by PEG 20,000, in stepwise, increasing concentrations. Cross-sensitization to polysorbate 80 and poloxamer 407 was assessed. SPT was performed in 16 healthy controls. In vitro basophil histamine release (HR) test and passive sensitization HR test were performed in patients and controls.

RESULTS

Patients previously testing positive on SPT to PEG 3000 and/or 6000 also tested positive to PEG 20,000. Patients with a longer interval since diagnosis tested negative to lower MW PEGs and positive mainly to higher concentrations of PEG 20,000. Three patients developed systemic urticaria during SPT. Eight patients showed cross-sensitization to poloxamer 407 and 3 to polysorbate 80. All controls tested negative. In vitro tests showed limited usefulness.

CONCLUSIONS

Skin test reactivity to PEG can decrease over time, but titrated SPT with increasing concentrations of PEG 20,000 can be diagnostic when lower MW PEGs test negative. To avoid systemic reactions, stepwise SPT is mandatory.

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.

Perioperative Allergic Reactions: Allergy Assessment and Subsequent Anesthesia

BACKGROUND

Evidence-based guidelines are needed in the United States to improve evaluation of perioperative allergic reactions including recommendations for subsequent anesthesia.

OBJECTIVE

To identify causative agent(s) and evaluate patients' tolerability of subsequent anesthesia in patients evaluated by Allergy/Immunology (A/I) at Massachusetts General Hospital.

METHODS

We performed a retrospective review of patients referred to the outpatient A/I clinic for perioperative allergic reactions between October 2003 and May 2017. Patient demographics, atopic history, and prior adverse drug reactions were reviewed. Patients underwent a comprehensive evaluation with testing including skin testing (ST), drug challenges (when appropriate), tryptase level measurement, and specific IgE to latex measurement. Tolerance of subsequent procedures requiring anesthesia was assessed.

RESULTS

Of 123 patients referred, 74 (60%) were female and the mean age was 46 (±18) years. At least 1 causative agent was identified in 28 patients (24%, n = 28 of 118). Seventeen of 28 (61%) patients were ST positive to an antibiotic, including 13 (46%) positive to cefazolin; 3 patients (11%) had a positive latex specific IgE. Of 85 patients who had subsequent anesthesia with a known outcome, 78 (91%) did not have another perioperative allergic reaction. Two of 5 patients with an elevated baseline tryptase level did not tolerate subsequent anesthesia.

CONCLUSION

The majority of patients safely received subsequent anesthesia after comprehensive A/I evaluation for their perioperative allergic reactions; however, improved algorithmic care is needed in the United States. Among ST-positive patients (24%), antibiotics (especially cefazolin) were the most common culprits. An elevated baseline tryptase level was associated with an increased risk of recurrent perioperative allergic reactions.

Should oral chlorhexidine remain in ventilator-associated pneumonia prevention bundles?

Ventilator-associated pneumonia (VAP) is related with high mortality, duration of mechanical ventilation and costs. Recent studies have questioned the safety and effectiveness of oral chlorhexidine to prevent VAP. We sought to verify whether the adverse effects of this substance outweigh its benefits. We searched several databases and selected studies that investigated the use of oral chlorhexidine and its impact on mortality. No association between oral chlorhexidine and lower VAP rates was found on meta-analyses of double-blind randomized trials, however significant increase in mortality was reported. It is speculated that chlorhexidine can cause damage to several organic sectors and cytotoxicity. Although it still can be beneficial in specific settings, robust evidence to recommend its routine application for all mechanically ventilated patients is lacking; therefore, given the possibility of harm, it would be better to follow the principle of non-maleficence until more studies becomes available.

Perioperative approach of allergic patients

Perioperative allergic reactions are rare, yet important complications of anesthesia. Severe, generalized allergic reactions called anaphylaxis are estimated to have a mortality of 3.5-4.8%. Adequate recognition and handling of a severe perioperative anaphylactic reaction result in better outcomes, including less hypoxic-ischemic encephalopathy and death. The diagnosis of a perioperative allergic reaction can be difficult as the list of possible culprits of a perioperative allergic reaction is extensive. Making an informed guess on the causative agent and avoiding this agent in future anesthesia procedures is undesirable and unsafe. Therefore, to ensure future patient safety, a thorough investigation following a perioperative allergic reaction is mandatory. A collaborate approach by allergists and anesthesiologists is advised. In this article, we discuss the basic approach of the allergic patient and of patients with a suspected allergy to perioperatively administered medication.

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.

Antiseptic efficacy of an innovative perioperative surgical skin preparation: A confirmatory FDA phase 3 analysis

BACKGROUND

An innovative approach to perioperative antiseptic skin preparation is warranted because of potential adverse skin irritation, rare risk of serious allergic reaction, and perceived diminished clinical efficacy of current perioperative antiseptic agents. The results of a confirmatory US Food and Drug Administration (FDA) phase 3 efficacy analysis of a recently approved innovative perioperative surgical skin antiseptic agent are discussed.

METHODS

The microbial skin flora on abdominal and groin sites in healthy volunteers were microbiologically sampled following randomization to either ZuraGard, a 2% chlorhexidine/70% isopropyl alcohol preparation (Chloraprep), or a control vehicle (alcohol-free ZuraGard). Mean log10 reduction of colony-forming units (CFU) was assessed at 30 seconds, 10 minutes, and 6 hours.

RESULTS

For combined groin sites (1,721 paired observations) at all time points, the mean log10 CFU reductions were significantly greater in the ZuraGard group than in the Chloraprep group (P < .02). Mean log10 CFU reductions across combined abdominal and groin sites at all time points (3,277 paired observations) were significantly greater in the ZuraGard group than in the Chloraprep group (P < .02).

CONCLUSIONS

A confirmatory FDA phase 3 efficacy analysis of skin antisepsis in human volunteers documented that ZuraGard was efficacious in significantly reducing the microbial burden on abdominal and groin test sites, exceeding that of Chloraprep. No significant adverse reactions were observed following the application of ZuraGard.

TRIAL REGISTRATION

ClinicalTrials.gov identifiers: NCT02831998 and NCT02831816.

Multi-Center Outcomes of Chlorhexidine Oral Decontamination in Intensive Care Units

Background: The efficacy of oral chlorhexidine (oCHG) for decontamination in intensive care unit (ICU) patients is controversial. The purpose of this study was to evaluate the effect of oCHG decontamination on the incidence of pneumonia, sepsis, and death in ICU patients. Methods: The Philips eICU database version 2.0 was queried for patients admitted to the ICU for ≥48 hours in 2014-2015. The primary outcome of interest was death in the ICU. Secondary outcomes were a diagnosis of pneumonia or sepsis. Patients with pneumonia or sepsis diagnosed within the first 48 hours of ICU admission were excluded from the outcome analyses. Univariable analysis was performed comparing age, gender, race, severity of illness scores, hospital characteristics, and oCHG order. Multivariable logistic regression was performed using univariable results with p < 0.05. Results: Of the 64,904 patients from 186 hospitals, 22.1% (n = 14,333) had oCHG ordered. The overall mortality rate was 6.9% (n = 4,449) and the mortality rate in patients receiving oCHG was 10.6% (n = 1,518; p < 0.001). After controlling for confounding factors, oCHG remained an independent risk factor for death (odds ratio [OR] 1.25; 95% confidence interval [CI] 1.16-1.34). After excluding patients with an early diagnosis of pneumonia, the overall pneumonia incidence was 2.6% (n = 1,431) and the incidence in patients having oCHG was 4.2% (n = 517; p < 0.001). However, multivariable logistic regression revealed no significant difference in the risk of pneumonia with oCHG (OR 0.97; 95% CI 0.85-1.09). After excluding patients with an early diagnosis of sepsis, the overall rate of sepsis was 1.8% (n = 949) and for patients with oCHG, the rate was 3.3% (n = 388; p < 0.001). After controlling for other confounders, oCHG remained an independent risk factor for sepsis (OR 1.37; 95% CI 1.19-1.59). Conclusions: A chlorhexidine mouthwash order is associated with increased odds of death and sepsis without decreased odds of pneumonia in a heterogeneous cohort of ICU patients. Additional studies are needed to understand better the effect of oCHG on outcomes.

Adverse drug reaction profile in Amravati region of India: A pharmacovigilance study

Background:

This pharmacovigilance study was conducted in Amravati region of central India to identify the nature and prevalence of adverse drug reactions, which will be helpful for better drug prescription practice and management of diseases.

Materials and Methods:

Adverse drug reaction reporting forms from April 2016 to March 2019, were collected from the pharmacovigilance center, which include details of demographics, investigations, concomitant drug history, and details of present complaints including reaction details, onset, recovery, drug information, hospitalization, management, and assessment.

Results:

A total of 19 cases were reported. Approximately 47.4% male and 52.6% female experienced the reactions with age-group ranging from 15 to 75 years. The most common adverse drug reactions were caused by antimicrobial agents (47.6%) followed by other group of drugs (37%) and nonsteroidal anti-inflammatory drugs (15.9%). Polypharmacy was the most common cause (31.6%) with the most common route being intravenous (42.1%). Skin reactions were the most common (84.2%). Antitubercular drugs were more commonly responsible for exfoliative lesions, whereas paracetamol and unknown drugs were responsible for multiple ulcerative lesions. Reactions to antitubercular drugs were considered as possible (15.8%), whereas with other drugs (63.2%), it was probable.

Conclusion:

It is a tip of the iceberg, which provides important demographic details in which adverse drug reactions were reported. Cutaneous reactions due to common drugs are responsible for hospitalization of the patients. There is an urgent need of training for health-care providers so that reporting can be improved and better picture can emerge.

An EAACI position paper on the investigation of perioperative immediate hypersensitivity reactions

Perioperative immediate hypersensitivity reactions are rare. Subsequent allergy investigation is complicated by multiple simultaneous drug exposures, the use of drugs with potent effects and the many differential diagnoses to hypersensitivity in the perioperative setting. The approach to the investigation of these complex reactions is not standardized, and it is becoming increasingly apparent that collaboration between experts in the field of allergy/immunology/dermatology and anaesthesiology is needed to provide the best possible care for these patients. The EAACI task force behind this position paper has therefore combined the expertise of allergists, immunologists and anaesthesiologists. The aims of this position paper were to provide recommendations for the investigation of immediate-type perioperative hypersensitivity reactions and to provide practical information that can assist clinicians in planning and carrying out investigations.

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.

Peri-Operative Anaphylaxis-An Investigational Challenge

Patients with suspected peri-operative anaphylaxis (POP) require thorough investigation to identify underlying trigger(s) and enable safe anesthesia for subsequent surgery. The changing epidemiology of POP has been striking. Previous estimates of the incidence of POP have ranged between 1:6,000 and1:20,000 anesthetics, but more recent data from France and the United Kingdom suggest an estimated incidence of 1:10,000. Other important changes include a change in the hierarchy of well-recognized triggers, with antibiotics (beta-lactams) supplanting neuromuscular blockers (NMB) as the leading cause of POP. The emergence of chlorhexidine, patent blue dye, and teicoplanin as important triggers have also been noteworthy findings. The mainstay of investigation revolves around critical analysis of the time-line of events leading up to anaphylaxis coupled with judicious skin testing. Skin tests have limitations with respect to unknown predictive values for most drugs/agents and therefore, knowledge of background positivity in healthy controls, test characteristics of individual drugs and the use of non-irritant concentrations is essential to avoid both false-positive and false-negative results. Specific IgE assays for individual drugs are available only for a limited number of agents and are not a substitute for skin testing. Acute serum total tryptase has a high specificity and positive predictive value in IgE-mediated POP anaphylaxis but is limited by its moderate sensitivity and negative predictive value. Planning for safe anesthesia in this group of patients is particularly challenging and consequently anesthetists need to be alert to the possibility of repeat episodes of anaphylaxis. Because of the limitations of current investigations for POP, collecting systematic data on the outcome of repeat anesthesia is valuable in validating current investigatory approaches. This paper reviews the changing epidemiology of POP with reference to the main triggers, and the investigation and outcome of subsequent anesthesia.

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.

Chlorhexidine Allergy: Mild Allergic Reactions Can Precede Anaphylaxis in the Healthcare Setting

Chlorhexidine can cause severe immediate-type allergic reactions such as urticaria, anaphylactic shock or, even, cardiac arrest. We report the case of a patient who developed perioperative anaphylactic shock caused by chlorhexidine 1 year after a postoperative urticarial reaction, which was assumed not to be significant at the time. This case highlights the importance of identifying mild allergy symptoms after exposure to chlorhexidine at the pre-anaesthetic assessment to prevent more severe allergic reactions in future.

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.

Sugammadex hypersensitivity and underlying mechanisms: a randomised study of healthy non-anaesthetised volunteers

BACKGROUND

We investigated potential for hypersensitivity reactions after repeated sugammadex administration and explored the mechanism of hypersensitivity.

METHODS

In this double-blind, placebo-controlled study (NCT00988065), 448 healthy volunteers were randomised to one of three arms to receive three repeat i.v. administrations of either sugammadex 4 mg kg^-1, 16 mg kg^-1, or placebo. Primary endpoint was percentage of subjects with hypersensitivity (assessed by an independent adjudication committee). Secondary endpoint of anaphylaxis was classified per Sampson and Brighton criteria. Exploratory endpoints included skin testing, serum tryptase, anti-sugammadex antibodies [immunoglobulin (Ig) E/IgG], and other immunologic parameters.

RESULTS

Hypersensitivity was adjudicated for 1/148 (0.7%), 7/150 (4.7%), and 0/150 (0.0%) subjects after sugammadex 4 mg kg^-1, 16 mg kg^-1, and placebo, respectively. After sugammadex 16 mg kg^-1, one subject met Sampson criterion 1 and Brighton level 1 (highest certainty) anaphylaxis criteria; two met Brighton level 2 criteria. After database lock it was determined that certain protocol deviations could have introduced bias in the reporting of hypersensitivity signs/symptoms in a subject subset. Objective laboratory investigations indicated that potential underlying hypersensitivity mechanisms were unlikely to have been activated; the results suggest that most of the observed hypersensitivity reactions were unlikely IgE/IgG-mediated.

CONCLUSION

Dose-dependent hypersensitivity or anaphylaxis reactions to sugammadex were observed when administered without prior neuromuscular blocking agent. Laboratory investigations do not suggest prevalent allergen-specific IgE/IgG-mediated immunologic hypersensitivity. Because it could not be fully excluded that estimates of hypersensitivity/anaphylaxis incidence were unbiased, an additional study was conducted to characterise the potential for hypersensitivity reactions and is described in a companion report.

CLINICAL TRIAL REGISTRATION

http://www.clinicaltrials.gov NCT00988065; Protocol number P06042.

Immediate-type hypersensitivity to polyethylene glycols: a review

Polyethylene glycols (PEGs) or macrogols are polyether compounds widely used in medical and household products. Although generally considered biologically inert, cases of mild to life-threatening immediate-type PEG hypersensitivity are reported with increasing frequency. Nevertheless, awareness of PEG's allergenic potential remains low, due to a general lack of suspicion towards excipients and insufficient product labelling. Information on immediate-type reactions to PEG is limited to anecdotal reports, and the potential for PEG sensitization and cross-sensitization to PEGylated drugs and structurally related derivatives is likely underestimated. Most healthcare professionals have no knowledge of PEG and thus do not suspect PEG's as culprit agents in hypersensitivity reactions. In consequence, patients are at risk of misdiagnosis and commonly present with a history of repeated, severe reactions to a range of unrelated products in hospital and at home. Increased awareness of PEG prevalence, PEG hypersensitivity, and improved access to PEG allergy testing, should facilitate earlier diagnosis and reduce the risk of inadvertent re-exposure. This first comprehensive review provides practical information for allergists and other healthcare professionals by describing the clinical picture of 37 reported cases of PEG hypersensitivity since 1977, summarizing instances where PEG hypersensitivity should be considered and proposing an algorithm for diagnostic management.