Hypersensitivity to local anaesthetics--update and proposal of evaluation algorithm

Comprehensive management evaluation of anaphylactic shock in dental clinics across developing countries

Anaphylaxis shock is defined as a sudden, severe allergic reaction that can be life-threatening and typically occurs within minutes to a few hours following exposure to a triggering substance. While anaphylaxis shock can be a rare side effect of dental treatments, including sedation and anesthesia, dentists must be prepared to respond promptly and appropriately to prevent complications such as airway obstruction and cardiac issues. In developing countries, managing anaphylactic shock presents challenges, often due to low awareness among dentists and a lack of necessary equipment. Immediate diagnosis and management are crucial in a dental setting when anaphylaxis shock occurs. Therefore, dental practitioners must be trained to diagnose and manage such situations effectively. A lack of comprehensive understanding of allergy testing, diagnosis, and management can have serious consequences.

Anaphylactic shock during SpaceOAR Vue hydrogel procedure

In this report, we present a unique and rare case of an intraoperative anaphylactic shock leading to cardiac arrest during the SpaceOAR Vue™ hydrogel procedure in a 70-year-old patient undergoing External Beam Radiation Therapy (EBRT) for advanced localized prostate cancer. To our knowledge, this is the first urologic case report documenting this adverse reaction associated with the placement of the SpaceOAR Vue product. We discuss the possible culprits, including the hydrogel's polyethylene glycol (PEG) and iodine content, perioperative antibiotics, and local lidocaine anesthetic, and propose relevant considerations for clinicians administering rectal hydrogel spacers.

Diagnosis and Treatment of Perioperative Allergic Complications: A Practical Review

Background

Reported drug allergies are commonly encountered by surgeons and can lead to uncertainty in selecting an appropriate agent due to concerns of associated risks with related and cross-reactive drugs. This uncertainty can ultimately lead to increased infection rates.

Methods

A literature review was conducted in PubMed using a combination of the terms "allergy," "allergic reaction," "anaphylaxis," and "surgery," "surgical," or "operating room" for articles published within the last 10 years. Publications identified with these search terms were then filtered for review articles, sorted by "best match," and a maximum of 100 articles were manually reviewed for each combination of search terms.

Results

Search results yielded 46,484 articles, 676 of which were ultimately included for manual review, based on selection criteria. Specifically, articles selected for inclusion focused on surgical allergic reactions that were either related to mechanism of action, causative agent for the allergic reaction, timing of allergic reaction, or recommendations for appropriate management.

Conclusions

Allergic reactions can be a common occurrence in the operative room. Knowledge of likely causative agents, timing of a reaction to various agents, and appropriate management in the immediate and delayed setting can improve outcomes and safety for plastic surgery patients.

Urticaria After Lidocaine Use for Pecto-Intercostal Nerve Block

Urticaria within one hour of lidocaine injection is a sign of type I (immediate) hypersensitivity to lidocaine, yet most patients suspected of having a lidocaine allergy do not exhibit urticaria. Aside from being a sign of a rare lidocaine allergy, urticaria can also be a symptom of COVID-19. COVID-19 patients who experience urticaria after receiving lidocaine require careful evaluation to determine the cause. Here, we present a case of a patient exhibiting urticaria one hour after a lidocaine injection for the Pecto-intercostal nerve block to treat COVID-19-induced costochondritis.

Cardiac arrest in a 36 year-old after trigger point injection with lidocaine: Case report

A typical vasovagal response is characterized by bradycardia and paradoxical vasodilation. It is oftentimes self-limited and spontaneously reversible; however, severe cases can result in significant complications. This report describes a case of profound vasovagal syncope with subsequent cardiac arrest in the setting of receiving a trigger point injection. This patient presented to an outpatient clinic for ultrasound-guided left trapezius, levator scapulae, and rhomboid trigger point injections for relief of myofascial pain. One milliliter of 1% lidocaine was injected into the first trigger point when she stated she felt dizzy before becoming unresponsive without palpable peripheral pulses. The patient regained consciousness following cardiopulmonary resuscitation (CPR). Considering the frequency of office based pain procedures, it is important to recognize the potential serious complications associated with procedures frequently thought to be benign.

Anaphylactic reactions to local anesthetics in dental practice: a nationwide French retrospective study

OBJECTIVES

The primary aims of the present study were (1) to quantify and characterize anaphylactic type I reactions related to local anesthetics (LAs) drawing on the French Pharmacovigilance Database System over a 35-year period and (2) to focuse on reactions associated with dental procedures. The secondary aim was to infer an incidence rate in dental practice.

MATERIALS AND METHODS

All cases of anaphylactic reactions were selected using the algorithmic Standardized MeDRA Query "anaphylactic reaction." For each reaction, comprehensive data were collected, in particular the severity of symptoms, risk factors for anaphylaxis, and allergy testing. Imputability was assessed and a crude incidence rate in dental practice was estimated.

RESULTS

The first-line search identified 416 anaphylactic reactions, mostly of grade II (138) or III (240) severity. When restricted to dental practice, this number fell to 26 (grade I: 4; grade II: 10; grade III: 11; and grade IV: 1). Lidocaine was most often involved (81.49%) and mostly associated with anaphylactic reactions of grade II and III. Overall, 11 cases of fatal anaphylaxis were recorded, but no in dental practice. In dental practice, lidocaine was also the most frequently involved LA (57.69%).

CONCLUSIONS

All these findings highlight the very low incidence of type I-IgE-mediated reactions to LA, particularly in dental practice. The incidence rate of LA anaphylctic episodes in dental practice was estimated as 0.0261 anaphylactic episodes per million LA cartridges.

CLINICAL RELEVANCE

True anaphylactic reactions to LAs do occur and may justify a thorough investigation in dental practice.

Allergic Contact Dermatitis From Topical Drugs: An Overview

ABSTRACT

Allergic contact dermatitis from topical drugs is frequent and is seen in 10% to 17% of patients patch tested for suspected contact dermatitis. More than 360 drugs have been implicated as contact allergens, of which-generally-antibiotics, corticosteroids, local anesthetics, and nonsteroidal anti-inflammatory drugs are the most frequent culprits. This article provides an overview of allergic contact dermatitis to topical drugs, discussing their prevalence of sensitization, predisposing factors, clinical manifestations (both typical and atypical), the drugs described as allergens, cross-reactivity and coreactivity, and diagnostic procedures.

Lidocaine: A Local Anesthetic, Its Adverse Effects and Management

The most widely used medications in dentistry are local anesthetics (LA), especially lidocaine, and the number of recorded adverse allergic responses, particularly of hazardous responses, is quite low. However, allergic reactions can range from moderate to life-threatening, requiring rapid diagnosis and treatment. This article serves as a review to provide information on LA, their adverse reactions, causes, and management.

Vorteile, Sicherheit und Nebenwirkungen der Tumeszenz‐Lokalanästhesie bei dermatologischen Operationen an Säuglingen

Die Tumeszenz-Lokalanästhesie (TLA) spielt bei dermatochirurgischen Eingriffen eine wichtige Rolle. Die TLA bietet etliche Vorteile, wie lang anhaltende Betäubung, reduzierte Blutung während der Operation und Vermeidung möglicher Komplikationen einer Vollnarkose. Einfache Durchführung, günstiges Risikoprofil und breites Indikationsspektrum sind weitere Gründe dafür, dass TLA zunehmend auch bei Säuglingen eingesetzt wird. Es gibt nicht nur viele Indikationen für chirurgische Exzisionen im Säuglingsalter, wie angeborene Naevi, sondern es hat auch erhebliche Vorteile, wenn diese Exzisionen in einem frühen Alter durchgeführt werden. Dazu zählen die geringere Größe der Läsionen sowie die unproblematische Wundheilung und Geweberegeneration im Säuglingsalter. Dennoch müssen hinsichtlich der Anwendung der TLA bei Säuglingen einige Aspekte berücksichtigt werden, darunter die Dosierung, eine veränderte Plasmaproteinbindung und die Notwendigkeit einer adäquaten und lang anhaltenden Schmerzkontrolle.

Labor Epidural in a Patient Who is Allergic to Lidocaine: A Case Series

Continuous epidural anesthesia is considered the best modality for pain relief during labor, local anesthetic allergy is an uncommon occurrence but if a patient has an allergy to bupivacaine or lidocaine owing to its cross-reactivity with bupivacaine then it becomes very challenging to manage labor analgesia. A direct challenge test to rule out actual hypersensitivity was not considered a viable option given the risks involved if a severe allergic reaction occurred with the test dose. Using IV opioid-based analgesia has harmful effects for both mother and the baby in addition to decreasing participation of mothers in the birthing process owing to its sedative properties. We report two cases where the mother had a history of lidocaine allergy, so labor analgesia was managed using chloroprocaine patient-controlled epidural analgesia (PCEA).

Benefits, safety and side effects of tumescent local anesthesia in dermatologic surgery in infants

Tumescent local anesthesia (TLA) plays an important role in dermatosurgical procedures. TLA has several benefits such as long-lasting anesthesia, reduced bleeding during surgery and the avoidance of general anesthesia-associated complications. Convenience and a favorable risk profile along with a broad spectrum of indications are further reasons why TLA is increasingly applied in infants as well. There are not only a variety of indications for surgical excisions in infancy, such as congenital nevi, but also substantial benefits when performing these excisions at an early age. These include the smaller size of the lesions as well as the unproblematic wound healing and tissue regeneration in infancy. Nevertheless, several aspects need to be considered when applying TLA in infants including dosing, altered plasma protein binding and the need for adequate and long-lasting pain control.

Identification of Risk Factors and Cross-Reactivity of Local Anesthetics Hypersensitivity: Analysis of 14-Years' Experience

Purpose

Local anesthetics (LA) are widely used and adverse drug reactions (ADR) occur in 2.5–10%, but hypersensitivity reactions are rare (ranging between 0% and 4.3%). Risk is so overestimated causing too many allergy clinic referrals. There are limited and also conflicting results over the management of LA allergy. We aimed to find out who should be referred to an allergy clinic for a LA allergy testing, to define the subjects with an increased risk of LA allergy and to assess the need for testing for identifying alternative LA.

Patients and Methods

We performed a retrospective study of patients referred to our clinic for diagnostic workup of LA hypersensitivity from 2006 to 2020.

Results

In our cohort of 398 patients, tests were positive in 14 (3.52%) of them. Personal history of ADR with LA was the only independent risk factor for positive test (RR=4.007, p=0.033). Presence of generalized cutaneous symptoms and hypotension during past reaction were independent predictors of positive test (RR=9.043, p=0.021 and RR=10.445, p=0.038, respectively). The negative predictive value of intradermal test at dilution of 1:100 for immediate-type reaction was high (97.56%). Also, we demonstrated cross-reactivity within the amide-group LAs and co-occurrence of immediate- and delayed-type reactions.

Conclusion

Only patients with an LA-induced ADR should be referred to an allergy clinic. History of generalized cutaneous symptoms and/or hypotension during the reaction may define subjects with an increased risk of LA allergy. A stepwise test procedure may start with skin tests especially for these patients with increased risk factors. In presence of LA allergy, alternative LA should always be confirmed by performing a challenge test.

The effect of topical lidocaine on intradermal testing in atopic dogs

BACKGROUND

Intradermal testing (IDT) most often requires sedation. Topical lidocaine offers an adjunct or alternative to sedation.

HYPOTHESIS/OBJECTIVES

We hypothesized that topical lidocaine would significantly reduce reactions to intradermal injections and that atopic dogs treated with topical lidocaine would have similar results with IDT to atopic dogs tested without topical lidocaine.

ANIMALS

Fifteen client-owned atopic dogs.

METHODS

In Part I, a 5% lidocaine patch, 5% lidocaine cream and a control with no active ingredients were compared. The lowest pain score during intradermal injection was established in six atopic dogs. Fifteen atopic dogs were enrolled in Part II, and lidocaine cream (found to be most effective in Part 1) was applied randomly to a single side of the thorax. An IDT was performed on each side of the chest. Subjective and objective scores of the control and lidocaine treatment sides were compared 15 and 30 min post-injection.

RESULTS

The 5% lidocaine cream had the greatest reduction in pain score associated with intradermal injection. There were no significant differences in mean wheal diameter for any evaluated allergen at any time point between the control and lidocaine-treated sides. There was high agreement between the two groups when assessing the subjective score for all but one allergen.

CONCLUSIONS AND CLINICAL IMPORTANCE

Topical lidocaine may be used as adjunctive analgesia during IDT with caution in interpretation of subjective house dust scoring. Lidocaine cream appeared to reduce pain score and may allow reduction in concurrent sedation.

Risk of True Allergy to Local Anesthetics: 10-Year Experience from an Anesthesia Allergy Clinic in China

Background

Local anesthetics (LAs) have been widely used throughout the healthcare settings, especially in local anesthesia and pain management. The incidence of allergic reactions to LAs remains uncertain. The danger of allergic reactions to the use of LAs in every day of clinical practice is a matter of great concern. Therefore, it is necessary to investigate the risk of true allergy to LAs.

Methods

This study retrospectively evaluated the medical records of patients who were referred to an anesthesia allergy clinic in China and underwent allergy tests with LAs over a 10-year period from 2009 to 2019. The following information was collected from medical records: demographics of the patients, reasons for referral, clinical features of drug hypersensitivity reaction (DHR), and test results with LAs. Skin tests combined with an in vitro method, basophil activation test (BAT), were used to investigate allergic reactions to LAs.

Results

A group of 109 patients were included in the analysis. The main reason for referral was the presence of a suspected DHR after procedures with LAs (n=68, 62%), the second most common reason for referral was a history of DHR to other drugs and the need to use LAs for upcoming procedures (n=41, 38%). Of the 68 patients with a suspected DHR to LAs, only six cases presented true allergy and showed positive results in skin tests and/or BAT. And all 41 patients who had a history of DHR to other drugs presented negative in all tests.

Conclusion

Risk of true allergy to LAs may be very low. However, patients with a suspected history of DHR to LAs should be considered for allergy tests. Skin tests and BAT may be useful in the investigation and diagnosis of true allergy to LAs in clinical practice.

Allergische Reaktion vom Typ IV auf Prilocain nach Anwendung von Tumeszenz-Lokalanästhesie – eine seltene Komplikation

Allergische Typ-IV-Reaktionen in Form einer allergischen Kontaktdermatitis auf Lokalanästhetika vom Amid-Typ wie Lidocain, Bupivacain, Mepivacain und Prilocain sind selten. Wir berichten über eine Patientin mit einer Typ-IV-allergischen Reaktion auf Prilocain nach subkutaner Infiltration von Tumeszenz-Lokalanästhesie auf Prilocain-Basis im Rahmen einer Varizen-Operation, die zu einem allergischen Kontaktekzem mit Blasenbildung führte. Wir behandelten mit systemischen und lokalen Steroiden. Im Verlauf erfolgte eine allergologische Diagnostik mittels Epikutantestung. Die Ergebnisse zeigten sich positiv für Prilocain ebenso wie für Lidocain und Articain und negativ für die restlichen getesteten Lokalanästhetika. Eine später durchgeführte subkutane Provokation präsentierte eine gute Verträglichkeit von Procain und Mepivacain als Ausweichpräparate.

Allergic Contact Dermatitis to Pramoxine (Pramocaine)

Prescription and over-the-counter topical anesthetics are commonly used. Although allergy to amide and ester anesthetics is known, little has been reported on the nonamide, nonester pramoxine (pramocaine). This article briefly reviews allergy to topical anesthetics, provides detailed information on pramoxine, and describes characteristics of multiple patients with positive, relevant reactions to pramoxine.

Does Lidocaine Cause False Positive Results on Cocaine Urine Drug Screen?

BACKGROUND

Individuals who have tested positive for cocaine have claimed that lidocaine, or its primary metabolite, norlidocaine (monoethylglycinexylidide (MEGX)), have caused false positive results for the cocaine metabolite benzoylecgonine (BE) on urinary immunoassay testing.

OBJECTIVE

The goal of the study was to determine if lidocaine exposure from routine medical procedures can result in false positives on a commercially available cocaine immunoassay urine drug screen (UDS).

METHODS

We performed a cross-sectional observational study of patients receiving lidocaine as part of their regular care. Standard immunoassay drug screens and confirmatory liquid chromatography-mass spectrometry (LC-MS) were performed on all urine samples to assess for MEGX and BE.

RESULTS

In total, 168 subjects were enrolled; 121 samples positive for lidocaine were ultimately included for analysis. One hundred fourteen of the 121 were also positive for MEGX. None of the 121 were positive for cocaine/BE on the UDS (95% CI), 0-3.7% for the full sample and 0-3.9% for the 114 who tested positive for MEGX.

CONCLUSION

The present study found no evidence that lidocaine or norlidocaine are capable of producing false positive results on standard cocaine urine immunoassays.

Anaphylactic reaction after local lidocaine infiltration for retraction of retained teeth

Although allergic reactions are not rare complications in drug use, anaphylaxis or anaphylactoid reactions to some widely used drugs can embarrass clinicians because anaphylaxis is not easily diagnosed at the time of the event and treatment is unfamiliar to many. Lidocaine is a very popular drug in dental procedures and anaphylactoid reaction to it has been rarely reported. Clinicians who use lidocaine daily should, however, be aware of the possibility of anaphylaxis after its use. Once it occurs, anaphylaxis can be fatal, but if it is quickly diagnosed or suspected, treatment is simpler than most clinicians believe. An 86-year-old woman experienced an anaphylactic reaction 30 min after local infiltration of lidocaine for retraction of retained teeth. The dentist called an anesthesiologist for assistance. Fortunately, an anaphylactic reaction was quickly suspected and after subsequent rapid treatment with the administration of fluid and drug therapy, the patient recovered completely.

Lidocaine as a Rare and Hidden Allergen in the Perioperative Setting: A Case Report

Local anesthetics are used throughout the health care system. In the perioperative setting and in other settings of exposure to local anesthetics, true allergy is reported very rarely. We present an unusual case of immediate-type perioperative hypersensitivity to lidocaine with cross-reaction to mepivacaine, which was missed on initial investigation. This case illustrates that lidocaine may be a "hidden allergen" in the perioperative setting and should always be considered a potential culprit in cases of suspected perioperative hypersensitivity. The case also demonstrates that suspected perioperative hypersensitivity requires highly specialized investigation and close collaboration between allergists and anesthesiologists.

Differential diagnosis of late-type reactions to injected local anaesthetics: Inflammation at the injection site is the only indicator of allergic hypersensitivity

BACKGROUND

Anaphylaxis-like reactions developing within a few minutes are the most frequent complications of subcutaneous or submucosal injections of local anaesthetics (LAs), and topically applied LAs are potential contact allergens. In addition, injected LAs have been reported to induce delayed reactions, including local inflammation at the injection site, and various general symptoms.

OBJECTIVES

To assess the frequency and symptoms of late-type hypersensitivity occurring several hours after LA injections.

METHODS

We retrospectively evaluated clinical data and test results from all patients referred to our allergy clinic in a period of 20 years for diagnostic work-up of LA-associated late-type reactions.

RESULTS

Of 202 patients reporting symptoms with onset at least 1 hour after LA injection, 40 had cutaneous inflammation confined to the injection site, and 162 reported various systemic symptoms. LA hypersensitivity could be excluded in all patients with systemic complaints by means of skin testing and subsequent subcutaneous provocation. In 8 of the 40 patients (20%) with local inflammatory reactions, late-type allergic LA hypersensitivity was confirmed.

CONCLUSIONS

Late-type LA allergy commonly causes inflammatory skin reactions confined to the injection site. Conversely, LAs are highly unlikely to trigger delayed systemic symptoms such as urticarial or exanthematous skin eruptions.

Twenty Years' Experience with Anaphylaxis-Like Reactions to Local Anesthetics: Genuine Allergy is Rare

BACKGROUND

Anaphylaxis-like reactions occur within minutes after the application of local anesthetics (LA), most commonly during dental interventions. Impressive symptoms including respiratory distress or loss of consciousness frequently give rise to a suspicion of allergy and may prompt patients and treating physicians to refuse future LA injections.

OBJECTIVE

Nonallergic mechanisms are responsible for the majority of LA-induced immediate-type reactions. In view of the preponderance of nonallergic reactions, the question arises whether genuine LA allergy may be missed during routine testing procedures.

METHODS

We retrospectively evaluated clinical data and test results from patients referred to our allergy clinic within the past 20 years for diagnostic workup of LA-induced immediate-type reactions.

RESULTS

Of 402 evaluated patients, 29 had an episode of acute urticaria within 30 minutes after LA injections, and the remaining 373 had a history of mainly subjective cutaneous, respiratory, cardiovascular, and neurological complaints. Of the patients reporting urticaria with or without angioedema, 14 were diagnosed with a spontaneous episode of urticaria, 13 had allergic or nonallergic reactions to other agents, and 2 had IgE-mediated LA allergy. LA allergy was definitely excluded by 771 subcutaneous provocation tests with skin test negative LA, thereby demonstrating the high predictive value of negative intradermal testing.

CONCLUSIONS

Skin testing and provocative LA challenge are useful to exclude LA allergy, and this testing procedure seems to be appropriate to identify the extremely rare cases with IgE-mediated LA allergy.

Continuous Epidural Analgesia Using an Ester-Linked Local Anesthetic Agent, 2-Chloroprocaine, During Labor: A Case Report

We report the use of the ester-linked local anesthetic, 2-chloroprocaine, for continuous epidural analgesia in a patient in labor with a history of allergic reaction to amide local anesthetics. The patient gave a reliable history of pruritus, hives, erythema, and swelling on her lower extremity after having received a preservative-free amide local anesthetic. This allergy had been confirmed by a dermatologist by her reports. The patient requested an epidural for labor analgesia that was placed successfully. After an initial bolus, a continuous infusion of 1.5% of 2-chloroprocaine was initiated to achieve satisfactory pain relief throughout an uneventful vaginal delivery.

Risk of Immediate-Type Allergy to Local Anesthetics Is Overestimated-Results from 5 Years of Provocation Testing in a Danish Allergy Clinic

BACKGROUND

Local anesthetics (LAs) are used in many health care settings and exposure during a lifetime is almost inevitable. Immediate-type allergy to LAs is considered rare among allergy experts but is commonly suspected by health care workers from other specialties, and by patients.

OBJECTIVE

The main aim of this study was to investigate the incidence of immediate-type allergy to LAs in our regional allergy clinic over the 5-year period 2010 to 2014.

METHODS

This was a retrospective single-center study of patients referred to a regional allergy clinic (excluding patients with perioperative reactions) with suspected immediate allergy to LAs, who had undergone subcutaneous provocation with 1 or more LAs. Patients were identified in the hospital clinical coding system and clinical information about the reaction and investigation results was obtained from their medical records.

RESULTS

A total of 164 patients (123 women/41 men; median age, 56 years; range, 7-89 years) who had 189 provocations with LAs were included over the 5-year period 2010 to 2014. All 164 patients had negative subcutaneous provocations to all 189 tests with LAs (95% CI, 0%-1.83%). Another allergen was identified in 10% (n = 17) of the patients.

CONCLUSIONS

None of the 164 patients with suspected immediate-type allergy to LAs reacted on provocation. Thus, no patients have been diagnosed with an immediate allergy to LAs in our regional allergy clinic in the 5-year period studied, and allergy to LAs must be considered very rare. Alternative mechanisms should be considered, but if symptoms are consistent with allergy, other potential allergens should be investigated.

Dental anesthesia for patients with allergic reactions to lidocaine: two case reports

Lidocaine, a local anesthetic commonly used in dental treatments, is capable of causing allergies or adverse effects similar to allergic reactions. However, the frequency of such occurrences in actual clinical settings is very rare, and even clinical tests on patients with known allergies to local anesthetics may often show negative results. When adverse effects, such as allergy to lidocaine, are involved, patients can be treated by testing other local anesthetics and choosing a local anesthetic without any adverse effects, or by performing dental treatment under general anesthesia in cases in which no local anesthetic without adverse effects is available. Along with a literature review, the authors of the present study report on two cases of patients who tested positive on allergy skin tests for lidocaine and bupivacaine and subsequently underwent successful dental treatments with either general anesthesia or a different local anesthetic.

Australian and New Zealand Anaesthetic Allergy Group Perioperative Anaphylaxis Investigation Guidelines

These guidelines are a consensus document developed by a working party of the Australian and New Zealand Anaesthetic Allergy Group (ANZAAG) to provide an approach to the investigation of perioperative anaphylaxis. They focus primarily on the use of skin testing as it is the investigation with the greatest clinical utility for the identification of the likely causative agent and potentially safer alternatives. The practicalities and process of skin testing, its limitations, and the place of other tests are discussed. These guidelines also address the roles of graded challenge and in vitro testing. The implications of anaphylaxis associated with neuromuscular blocking agents, beta-lactam antibiotics, local anaesthetic agents and chlorhexidine are discussed. Evidence for the recommendations is derived from literature searches using the words skin test, allergy, anaphylaxis, anaesthesia, and each of the individual agents listed in these guidelines. The individual articles were then reviewed for suitability for inclusion in these guidelines. Where evidence was not strong, as is the situation for many perioperative agents, expert consensus from the ANZAAG working party was used. These guidelines are intended for use by specialists involved in the investigation of perioperative allergy. They have been approved following peer review by members of ANZAAG and are available on the ANZAAG website: http://www.anzaag.com/anaphylaxis-management/testing-guidelines.pdf .

Investigation and diagnosis of an immediate allergy to amide local anaesthetic in a paediatric dental patient

Local anaesthetics remain the most common prescription medication utilized in dental practise. Adverse reactions following administration of local anaesthetic are somewhat common and are frequently reported as 'allergies'. However, of these events, it is estimated that only 1% are confirmed allergies to the local anaesthetic. This case report presents the process of referral for investigation and testing to confirm an amide local anaesthetic allergy in a paediatric patient. Testing for a safe alternative was also completed to identify local anaesthetic agents also of the amide variety that could be utilized safely on this individual. Following skin testing of alternative agents, intraoral challenges were completed. Finally, restorative dental treatment was provided safely for the patient with the use of an alternative amide local anaesthetic on a number of occasions with no further adverse outcomes.

Lidocaine Allergy: Do Positive Patch Results Restrict Future Use?

BACKGROUND

Adverse reactions from lidocaine are commonly reported. When allergy is suspected, patients may be referred for specific skin testing to confirm the association of their clinical findings.

OBJECTIVE

We aimed to investigate 13 cases of suspected lidocaine allergy to analyze if positive patch results restricted future use as an injectable local anesthetic.

METHODS

A prospective study was conducted from March 2013 to September 2014 at 2 academic hospital-based patch test clinics in Toronto. Patients were tested to the North American Contact Dermatitis Group standard series (Smart Practice, Phoenix, AZ) and, if suspicion for lidocaine allergy was high, a local anesthetic series (Chemotechnique Diagnostics, Malmö, Sweden) was added. Intradermal skin testing to local anesthetics below irritant concentrations was subsequently conducted in lidocaine-positive patients. If negative, a subcutaneous challenge with 1% lidocaine was done.

RESULTS

Thirteen of 756 patients patch tested were positive to lidocaine. Seven patients had relevant reactions to over-the-counter products containing lidocaine, 2 reacted to subcutaneous lidocaine, and 4 had incidental findings. There were no patients with positive results to intradermal testing. Three patients had delayed reactions to the subcutaneous challenge.

CONCLUSIONS

Patients with positive patch tests to lidocaine and negative results to intradermal testing and subcutaneous challenge may be safe to use lidocaine as an injectable local anesthetic in the future.

Allergy Testing and Drug Screening on an ITO-Coated Lab-on-a-Disc

A lab-on-a-disc (LOAD) is a centrifugal microfluidic set-up based on centrifugal force without using micro-pumps to drive reagents and cells to various chambers through channels and valves for reactions. A LOAD coated with conductive transparent indium tin oxide (ITO) for thermal control was developed to screen allergy-blocking agents. When the acridine orange (AO)-loaded KU-812 human basophilic cells were activated in the LOAD by stimuli, AO trapped in the cytoplasmic granules was released externally as an allergic mediator mimetic to report degranulation. This response was monitored by fluorescence when the released AO in supernatant had been transferred, with a higher spinning speed, from the reaction chamber to detection chamber in the LOAD where AO reacted with exogenous DNA. We report here the principles of the system and an improved LOAD set-up with the ITO-coated glass resistive microheater to run assays at 37 °C. By using this platform, we demonstrate here for the first time that triptolide, an active ingredient from the Chinese medicine herb Tripterygium wilfordii Hook f., was able to suppress the fMLP-mediated degranulation in basophils. This serves as an example how LOADs can be used to screen agents to alleviate symptoms of allergy.

A new method of topical anesthesia by using anesthetic solution in a patch

INTRODUCTION

We investigated the effects of topical anesthesia of the oral mucosa by using an adhesive patch instilled with 2% lidocaine hydrochloride solution.

METHODS

The subjects were 20 healthy adult volunteers who gave written informed consent. Each patient was treated in a randomized crossover fashion with a hemostatic adhesive patch instilled with one of the following agents: 2% lidocaine hydrochloride with 12.5 μg/mL epinephrine, 2% lidocaine hydrochloride, 20% ethyl aminobenzoate, or physiological saline solution. A cotton ball containing 20% ethyl aminobenzoate was also tested. The adhesive patch or cotton ball was placed on the gingivobuccal fold of the maxillary right canine for 2 or 5 minutes. Then, a 33-gauge or 30-gauge needle was inserted to a depth of 2 mm. Insertion pain was evaluated with a visual analog scale (VAS) and a 4-level verbal rating scale immediately after needle removal. Efficacy of analgesia was calculated from the verbal rating scale.

RESULTS

The VAS was lower and the efficacy of analgesia was higher on 33-gauge needle insertion than on 30-gauge needle insertion in all treatments. The VAS was also significantly lower and the efficacy of analgesia was higher in the lidocaine groups than in the other groups. Adding epinephrine did not enhance the anesthetic effect of lidocaine hydrochloride.

CONCLUSIONS

Topical mucosal anesthesia with an adhesive patch containing 2% lidocaine hydrochloride solution is simple and may be more effective than conventional methods.

The Rare Case of a Probably True IgE-Mediated Allergy to Local Anaesthetics

The majority of immediate type adverse reactions to local anaesthetics seem to be non-IgE-mediated. We report a case of a 31-year-old woman, who developed conjunctivitis and conjunctival erythema immediately after intrauterine application of a local anaesthetic. Skin prick testing and intradermal testing were done with lidocaine, mepivacaine, and procaine. Intradermal testing showed positive reactions to mepivacaine (1 : 10), undiluted lidocaine, and procaine (1 : 10 and undiluted). Specific IgE could be detected against mepivacaine, but not against latex. Serum tryptase was in the normal range. In order to rule out the exceptional case of a true IgE-mediated reaction, allergy testing with local anaesthetics is still required in the workup of patients.

New ways to detect adverse drug reactions in pediatrics

Adverse drug reactions (ADRs) complicate at least 5% of all courses of therapy for children. Dealing with an ADR requires a stepwise approach in appreciation of the possibility of an ADR, assessment of whether the adverse event in question is drug-related, assessment of causality, assistance in treating the symptoms of the ADR, and dealing with the aftermath of the event. Several new developments likely will improve the ability to assess, evaluate, treat, and prevent ADRs in children. These developments include tools to evaluate causality, laboratory tests to diagnose ADRs, pharmacogenomic approaches to prevent ADRs, and new insights into treating serious ADRs.

IgE-mediated allergy to local anaesthetics: separating fact from perception: a UK perspective

Local anaesthetic (LA) agents have been routinely used in dentistry, ophthalmology, minor surgery, and obstetrics since the late nineteenth century. Reports relating to adverse reactions and LA allergy have appeared in the published literature for several years. However, the incidence of true, IgE-mediated LA allergy remains uncertain and is presumed to be very low. We critically reviewed the English language literature on suspected LA allergy and its investigation with the aim of estimating the reported prevalence and analysing the role of different tests currently used to identify and confirm LA allergy. Twenty-three case series involving 2978 patients were identified and analysed. Twenty-nine of these patients had true IgE-mediated allergy to LA, thus confirming the reported prevalence of LA allergy in large series to be <1% (0.97%). The protocols used in the investigation of these patients have also been discussed. Evidence from this review confirms the rarity of IgE-mediated allergy to LA and supports an investigation strategy based on using the clinical history to select patients for skin testing and challenge. We believe that such a triage process would alleviate pressures on allergy services without compromising patient safety.