Alleged allergy to local anaesthetics

Neurological Complications of Local Anesthesia in Dentistry: A Review

Local anesthesia is a technique that temporarily desensitizes a specific body area, typically for a surgical procedure, dental work, or pain management. It is described as a sensation loss in a specific area of the body due to depression of excitation in the nerve endings or due to the inhibition of the conduction process within the peripheral nerves. It allows for safer and more comfortable medical procedures, reducing the need for general anesthesia and facilitating faster recovery. Local anesthesia is generally safe, but like any medical intervention, it carries potential risks and side effects. The complications related to local anesthetics can be assessed in terms of neurological, vascular, local, systemic, and neurological. In this review article, we discussed the neurological complications of local anesthesia related to the ophthalmic nerve, maxillary nerve, mandibular nerve, branches of the trigeminal nerve, and facial nerve. These include diplopia, ptosis, paralysis of the eye, blindness, paresthesia, trismus, soft tissue lesions, edema, hematoma, facial blanching, infection, allergy, overdose, neuralgia, facial palsy, etc.

Allergy to Local Anesthetics is a Rarity: Review of Diagnostics and Strategies for Clinical Management

Local anesthetics (LA) are commonly used in procedures and in topical agents for pain management. With the increasing use of LA drugs, the management of LA reactions is more frequently encountered in the office and in operating rooms. True allergic reactions involving IgE-mediated reactions and anaphylaxis are rare; they have only been identified in case reports and account for less than 1% of adverse LA reactions. Most reactions are non-allergic or are a result of hypersensitivity to other culprits such as preservatives, excipients, or other exposures. LA reactions that are misclassified as true allergies can lead to unnecessary avoidance of LA drugs or delays in surgical procedures that require their use. A detailed history of prior LA reactions is the first and most crucial step for understanding the nature of the reaction. Reactions that are suspicious for an immediate hypersensitivity reaction can be evaluated with skin prick and intradermal testing with subsequent graded challenge. Reactions that are suspicious for a delayed hypersensitivity reaction can be evaluated with patch testing.

Tutorial on Clinical Practice for Use of the Fiberoptic Endoscopic Evaluation of Swallowing Procedure With Adult Populations: Part 1

PURPOSE

Representatives of the American Board of Swallowing and Swallowing Disorders (AB-SSD) and American Speech-Language-Hearing Association (ASHA) Special Interest Group (SIG) 13: Swallowing and Swallowing Disorders (Dysphagia) developed this tutorial to identify and recommend best practice guidelines for speech-language pathologists who conduct and interpret fiberoptic endoscopic evaluation of swallowing (FEES) procedures in adults. This document also includes proposed training needs and methods for achieving competency. Expert opinion is provided regarding indications for performing the FEES exam, potential contraindications, adverse effects and safety, equipment and personal protection, the exam protocol, interpretation and documentation of findings, and training requirements to perform and interpret the exam.

CONCLUSIONS

This tutorial by the AB-SSD and SIG 13 represents the first update about the FEES procedure since ASHA's position paper and technical report published in 2004. Creation of this document by members of the AB-SSD and SIG 13 is intended to guide professionals who are training for or practicing FEES in the adult population toward established best practices and the highest standards of care.

Recent update on potential cytotoxicity, biocompatibility and preventive measures of biomaterials used in dentistry

Dental treatment is provided for a wide variety of oral health problems like dental caries, periodontal diseases, periapical infections, replacement of missing teeth and orthodontic problems. Various biomaterials, like composite resins, amalgam, glass ionomer cement, acrylic resins, metal alloys, impression materials, bone grafts, membranes, local anaesthetics, etc., are used for dental applications. The physical and chemical characteristics of these materials influence the outcome of dental treatment. It also impacts on the biological, allergic and toxic potential of biomaterials. With innovations in science and their positive results, there is also a need for awareness about the biological risks of these biomaterials. The aim of dental treatment is to have effective, yet safe, and long-lasting results for the benefit of patients. For this, it is important to have a thorough understanding of biomaterials and their effects on local and systemic health. Materials used in dentistry undergo a series of analyses before their oral applications. To the best of our knowledge, this is the first and original review that discusses the reasons for and studies on the toxicity of commonly used biomaterials for applications in dentistry. It will help clinicians to formulate a methodical approach for the selection of dental biomaterials, thus providing an awareness for forecasting their risk of toxic reactions.

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.

Management of anaphylaxis in the dental practice: an update

Anaphylaxis is a severe and potentially life-threatening allergic reaction that can occur in the dental practice. There are a number of dental-related causes including mouthwashes, local anaesthetics, latex and antibiotics. The dental team must be able to respond effectively and manage the life-threatening situation appropriately following Resuscitation Council UK guidelines. The timely administration of adrenaline is life-saving; any delays can lead to a poor outcome. With the current national supply issues with adrenaline auto-injector devices, there is an expectation that GDPs should be competent at drawing up adrenaline from an ampoule and administrating it intramuscularly. The aim of this article is to provide an update on the management of anaphylaxis in the dental practice with particular reference to the procedure for intramuscular injection of adrenaline.

Articaine as an alternative in lidocaine allergy: Case report of a seventy year old male patient

INTRODUCTION

Allergy to lidocaine is extremely rare but if it occurs, one should switch to an alternative drug and discontinue the use of lidocaine so that adverse consequences do not occur.

PRESENTATION OF CASE

We present the case of a 70 year old male patient who had come to our department to undergo extraction of his decayed teeth under local anesthesia.

DISCUSSION

He had history of allergy to lidocaine. Type IV hypersensitivity to lidocaine was confirmed by positive skin prick testing to the drug. Skin prick testing was also performed for articaine that was available with us, and the test was found to be negative without any wheal or flare reaction even after 72 h. Thus it was confirmed that he was non-allergic to articaine and successfully underwent exodontia by using the same.

CONCLUSION

Articaine can be a suitable alternative in patients with true lignocaine allergy and vice-versa. No cross-reactivity has been reported between lidocaine and articaine so far. However, the number of cases reported in the past are limited, hence more cases are required in the future to prove its authenticity.

Local anaesthesia in dentistry: a review

Over the past century, there is perhaps no greater contribution to the practice of clinical dentistry than the development and application of local anaesthesia. What were once considered painful procedures have now been made routine by the deposition and action of local anaesthetics. This article will serve as a review of basic pharmacological principles of local anaesthesia, subsequent sequelae that can arise from their use, considerations when using local anaesthetics, and recent advances in the delivery of local anaesthetics.

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.

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 .

No cases of perioperative allergy to local anaesthetics in the Danish Anaesthesia Allergy Centre

BACKGROUND

Local anaesthetics (LA) are often suspected as possible causes of allergic reactions. The Danish Anaesthesia Allergy Centre (DAAC) is the national reference centre for investigation of perioperative allergic reactions. The purpose of this study was to investigate the incidence of IgE-mediated immediate type perioperative allergic reactions to LA.

METHODS

In the period 2004-2013, a total of 409 patients (244 women/165 men; median age 49 years, range 1-86 years) were investigated in DAAC on suspicion of allergy associated with anaesthesia and surgery. A total of 162 (40%) patients were exposed to one or more LA. Suspected allergy to LA was investigated by prick test, intradermal test and subcutaneous provocation with the suspected drug. Patients with positive skin tests still underwent subcutaneous provocation, as false positive skin tests can occur.

RESULTS

A total of 203 test series with LA were carried out on 162 patients (89 women/73 men; mean age 49 years, range 2-85 years) with the following drugs: Lidocaine n = 80 (49%), bupivacaine n = 82 (51%), ropivacaine n = 31 (19%) and mepivacaine n = 10 (6%). All 162 patients had negative subcutaneous provocation for all tested LA (95% CI: 0-1.8%). Investigations revealed another allergen in 52 of 162 patients.

CONCLUSION

None of the 162 patients with suspected perioperative allergic reactions and exposure to LA reacted on subcutaneous provocation with the relevant LA. Thus, no patients have been diagnosed with allergy to LA in DAAC in the period 2004-2013 and allergy to LA must be considered very rare in this population.

Unusual Hypersensitivity Reaction to Iohexol During Epidural Steroid Injection Resulting in Lipoma Development: A Case Presentation

Epidural steroid injections are common interventional pain procedures for radicular pain when conservative therapies fail. We present the case of a 36-year-old woman with lumbar radicular pain who developed a hypersensitivity reaction to iohexol during a fluoroscopically guided interlaminar epidural steroid injection resulting in lipoma development. Mechanisms of anaphylactoid reaction and recommendations for lipoma treatment are described based on clinical presentation. With an increase in the number of injections performed for pain management, awareness of this complication may need to be included for informed consent.

LEVEL OF EVIDENCE

V.

Perioperative anaphylactic reactions: Review and procedure protocol in paediatrics

Perioperative anaphylactic reactions are immediate, hypersensitive reactions that are potentially life-threatening resulting from a sudden release of mediators from mast cells and basophiles, due to either immune (IgE or non-IgE mediated) or non-immune mechanisms. The most frequent causing agents are neuromuscular blocking agents (NMBAs), latex and antibiotics, with latex being the first cause in paediatrics. With regard to perioperative anaphylactic reactions, the usual early signs and symptoms of an anaphylactic reaction could be overlooked or erroneously interpreted and non-severe anaphylaxis could go undetected, with a risk of more severe reactions in the future. Using the data registered on the anaesthesia sheet, it is essential to establish a chronological relationship between drugs and/or substances administered and the reaction observed. An elevated level of tryptase confirms an anaphylactic reaction, but this does not usually increase in the absence of compromised circulation. An allergy study should be carried out preferably between 4 and 6 weeks after the reaction, using a combination of specific IgE, skin and controlled exposure tests (if indicated). Test sensitivity is good for NMBAs, latex, antibiotics, chlorhexidine, gelatine and povidone, and poor for barbiturates, opiates (these can give false positives since they are histamine releasers) and benzodiazepines. Special preventive measures should be taken, especially in the case of latex. We present the maximum concentrations recommended for skin tests, the recommended dosage to treat anaphylactic reactions in paediatrics and a procedure algorithm for the allergological study of these reactions.

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.

Local anesthesia: agents, techniques, and complications

This article outlines the different classes of local anesthetics available for dental procedures. It also gives an overview of the mechanism of action and metabolism of each different class of local anesthetic. Furthermore, it discusses indications and contraindications of each local anesthetic and the proper dosage of each. The techniques for the administration of local anesthetics with the relevant anatomy are explained. An overview is given of the possible complications that can occur because of local anesthetic use and their possible treatment options.

Perioperative allergy: uncommon agents

Anesthesia may often be considered as a high-risk procedure and anaphylaxis remains a major cause of concern for anesthetists who routinely administer many potentially allergenic agents. Neuromuscular blocking agents, latex and antibiotics are the substances involved in most of the reported reactions. Besides these three agents, a wide variety of substances may cause an anaphylactic reaction during anesthesia. Basically all the administered drugs or substances may be potential causes of anaphylaxis. Among them, those reported the most in literature include hypnotics, opioids, local anesthetics, colloids, dye, Non-Steroidal Anti-Inflammatory Drugs (NSAIDs), Iodinated Contrast Media (ICM), antiseptics, aprotinin, ethylene oxyde and formaldehyde, and protamine and heparins. No premedication can effectively prevent an allergic reaction and a systematic preoperative screening is not justified for all patients; nevertheless, an allergy specialist should evaluate those patients with a history of anesthesia-related allergy. Patients must be fully informed of investigation results, and advised to provide a detailed report prior to future anesthesia.

Allergic reactions to local anesthetics in dental patients: analysis of intracutaneous and challenge tests

Some dental patients have histories of adverse reactions to local anesthesia. The aim of the present study was to investigate the frequency of allergy to local anesthetics of dental patients who had histories of adverse reactions to local anesthesia based on the results of allergy tests in our institute over a period of 5 years. We investigated the past medical records of dental patients retrospectively, and twenty patients were studied. Three of the 20 showed a positive or false-positive reaction in the intracutaneous test, and one patient showed a false-positive reaction in the challenge test. Our results suggest that the frequency of allergy to local anesthetics is low even if patients have histories of adverse reactions to local anesthesia. However, allergy tests of local anesthetics should be performed in patients in whom it is uncertain whether they are allergic.

Life-threatening anaphylactic reaction after the administration of airway topical lidocaine

A 9-year-old boy who developed a life-threatening anaphylaxis reaction of the airway and subsequent dyspnea and circulation collapse because of instilled the topical lidocaine into the airway within 2 min before performing flexible bronchoscopy (FB). FB revealed swollen airway mucosa and extensive foamy secretion that severely compromised the ventilation lumen. Rapid detection with FB and immediate resuscitation, including prompt administration of epinephrine, volume expander, and positive pressure ventilation with pure oxygen via an endotracheal tube, were successfully save the patient's life.

Perioperative anaphylaxis

The incidence of immune-mediated anaphylaxis during anesthesia ranges from 1 in 10,000 to 1 in 20,000. Neuromuscular blocking agents are most frequently incriminated, followed by latex and antibiotics, although any drug or substance used may be a culprit. Diagnosis relies on tryptase measurements at the time of the reaction and skin tests, specific immunoglobulin E, or basophil activation assays. Treatment consists of rapid volume expansion and epinephrine administration titrated to symptom severity.

Suspected allergy to local anaesthetics: follow-up in 135 cases

BACKGROUND

Local anaesthetics (LA) are generally considered safe with respect to allergy. However, various clinical reactions steadily occur. Even though most reactions are manifestations of reflexes to perceptive stimuli, uncertainty often remains regarding a possible allergic mechanism. This uncertainty later leads to an avoidance of local anaesthesia and unnecessarily painful interventions, resource-consuming general anaesthesia or even the risk of re-exposure to other yet unidentified allergens. In the present study, follow-up procedures at an allergy clinic were analysed to examine the frequency of identified causative agents and pathogenetic mechanisms and evaluate the strength of the diagnostic conclusions.

METHOD

The medical records of 135 cases with alleged allergic reactions to LA were reviewed. Diagnoses were based on case histories, skin tests, subcutaneous challenge tests and in vitro IgE analyses.

RESULTS

Two events (1.5%) were diagnosed as hypersensitivity to LA, articaine-adrenaline and tetracaine-adrenaline, respectively. Ten reactions (7%) were diagnosed as IgE-mediated allergy to other substances including chlorhexidine, latex, triamcinolone and possibly hexaminolevulinate. As challenge testing was not consistently performed with the culprit LA compound, follow-ups were short of definitely refuting hypersensitivity in 61% of the cases. The reported clinical manifestations were in general diagnostically unspecific, but itch and generalised urticaria were most frequent in test-positive cases.

CONCLUSION

Reactions during local anaesthesia are rarely found to be an IgE-mediated LA allergy. Whenever the clinical picture is compatible with allergy, other allergens should also be tested.

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

Local anaesthetics (LA) are widely used drugs. Adverse reactions are rare but may be caused by delayed-type hypersensitivity reactions and probably also immediate-type reactions. As it is not always easy to clinically differ between these subtypes, allergy skin testing should be considered. Although numerous test protocols have been published, how patients with hypersensitivity reactions to LA are ideally evaluated remains a topic of discussion. This review attempts to generate a comprehensive update on allergic reactions to LA and to present an algorithm that can be used for the evaluation of patients suspected with immediate- and delayed-type immune reactions. Literature was examined using PubMed-Medline, EMBASE, Biosis and Science Citation Index. Based on the literature, the proposed algorithm may safely and rapidly distinguish between immediate-type and delayed-type allergic immune reactions.

Anaesthesia for patients with idiopathic environmental intolerance and chronic fatigue syndrome

BACKGROUND

Idiopathic environmental intolerance syndrome (IEI), formerly known as multiple chemical sensitivity syndrome (MCSS), and chronic fatigue syndrome (CFS) are controversial diseases and there is little information in the literature regarding the appropriate conduct of anaesthesia in such patients.

METHODS

We studied 27 patients referred to our anaesthetic allergy clinic with IEI and CFS and performed literature and web searches on anaesthesia in these disorders.

RESULTS

The patients had a significant incidence of adverse events related to anaesthesia which were not allergic in nature. The adverse effects usually occurred postoperatively and were self limiting. Patients with IEI and CFS are not at risk of anaphylaxis and there is no scientific evidence that any drug or technique is excessively hazardous. Neither our patients nor the review of the scientific literature supported available web-based recommendations for the anaesthetic management of patients with IEL and CFS.

CONCLUSIONS

We suggest that the anaesthetist may be best to use the technique they would use if the patient did not have CFS or IEI but avoid drugs to which there is a history of adverse response. Anaesthesia is likely to be associated with adverse effects in these patients but the effects are not likely to be severe. A series of recommendations for the safe and harmonious conduct of anaesthesia in patients with CFS and IEI are provided.

Obtaining a contact lens acquired electroretinogram in the presence of topical anesthetic hypersensitivity

Clinical circumstances often demand flexibility in electrodiagnostic procedures. We present a clinical case that required alteration of our routine full-field electroretinography technique. The patient presented with reports of allergy to Xylocaine (lidocaine) and refused the use of any type of topical anesthetic drops. This conflicted with our routine ERG method that combines the use of the Henkes Lovac hard contact lens and the topical anesthetic Alcaine (proparacaine hydrochloride). We acquired a successful electroretinogram without topical anesthesia by using a "piggy-back" system involving the interposition of a soft hydrophilic contact lens between the cornea and the recording hard lens. The procedure yielded excellent ERG recordings and was well tolerated. This non-routine technique was also compared to our standard ERG technique using a normal volunteer. It appears that this proposed "piggy-back" technique is a useful alternative to routine ERG procedure in cases of refusal/allergy to ophthalmic solutions and also potentially in cases where additional corneal protection is needed.

[Immediate reactions to local anesthetics: diagnostic and therapeutic procedures]

BACKGROUND

Despite the widespread use of local anesthetics and frequently reported adverse reactions, true IgE-mediated allergy to local anesthetics is extremely rare. We report on 80 patients seen in our department for adverse reactions to local anesthetics, and we propose a clinical strategy to confirm or rule out immediate allergy to local anesthetics.

PATIENTS AND METHODS

We retrospectively analyzed the medical files of all patients referred to our department by their doctor or dentist for suspected immediate allergic reaction to local anesthetics between September 2001 and May 2004. These patients underwent skin tests (prick test and intradermal tests) exploring immediate allergy.

RESULTS

Eighty cases were tested in our department during this period. The most common symptoms were facial edema or dizziness following injection of an anesthetic occurring between a few seconds and more than 48 hours after administration. The causative local anesthetics were of the amide group in 91% of cases and of the ester group in 9% of cases. Seventy-nine patients had negative skin tests, allowing us to eliminate the diagnosis of immediate allergy, and the anesthetic could be reinjected with good tolerability. One patient presented with positive skin tests to lidocaine and cross reactivity to mepivacaine.

COMMENTS

Adverse reactions to local anesthetics are common and are mostly of pharmacological or toxic origin. However, allergic accidents with local anesthetics are rare and are mostly of type IV involving specific T cells. Immediate allergy to local anesthetics remains extremely rare with less than 10 authentic documented cases being published to date. Skin tests offer a reliable method for exploring immediate allergy in our experience and we propose a diagnostic strategy to confirm or rule out immediate allergy to local anesthetics.

Scandinavian Clinical Practice Guidelines on the diagnosis, management and follow-up of anaphylaxis during anaesthesia

The present approach to the diagnosis, management and follow-up of anaphylaxis during anaesthesia varies in the Scandinavian countries. The main purpose of these Scandinavian Clinical Practice Guidelines is to increase the awareness about anaphylaxis during anaesthesia amongst anaesthesiologists. It is hoped that increased focus on the subject will lead to prompt diagnosis, rapid and correct treatment, and standardised management of patients with anaphylactic reactions during anaesthesia across Scandinavia. The recommendations are based on the best available evidence in the literature, which, owing to the rare and unforeseeable nature of anaphylaxis, mainly includes case series and expert opinion (grade of evidence IV and V). These guidelines include an overview of the epidemiology of anaphylactic reactions during anaesthesia. A treatment algorithm is suggested, with emphasis on the incremental titration of adrenaline (epinephrine) and fluid therapy as first-line treatment. Recommendations for primary and secondary follow-up are given, bearing in mind that there are variations in geography and resources in the different countries. A list of National Centres from which anaesthesiologists can seek advice concerning follow-up procedures is provided. In addition, an algorithm is included with advice on how to manage patients with previous suspected anaphylaxis during anaesthesia. Lastly, Appendix 2 provides an overview of the incidence, mechanisms and possibilities for follow-up for some common drug groups.

Anaphylaxis during anaesthesia: diagnostic approach

Correct management of anaphylaxis during anaesthesia requires a multidisciplinary approach with prompt recognition and treatment of the acute event by the attending anaesthesiologist, and subsequent determination of the responsible agent(s) with strict avoidance of subsequent administration of all incriminated and/or cross-reacting compounds. However, correct identification of the causative compound(s) and safe alternatives is not always straightforward and, too often, not done. This review is not intended to discuss acute management of anaesthesia-related anaphylaxis but summarizes the major causes of anaphylaxis during anaesthesia and the diagnostic approach of this rare but potentially life-threatening complication. Apart from general principles about the diagnostic approach, history taking and importance of tryptase quantification, more specific confirmatory diagnostic procedures are organized on the basis of the major causes of perioperative anaphylactic reactions.

Use of preservative-free lidocaine for cataract surgery in a patient allergic to “caines”

Although many patients have been labeled allergic to local anesthetics (LAs), true allergic reactions to LAs are rare. An 81-year-old woman with a history of procaine (Novocaine) allergy presented for cataract surgery. Skin testing showed sensitivity to amide and ester LAs. Further testing with preservative-free lidocaine was negative, suggesting the patient was allergic to ester LAs and preservatives found in amide anesthetic preparations. Cataract extraction was subsequently and uneventfully performed in both eyes with topical anesthesia using preservative-free lidocaine.

Prevention of anaphylactic reactions to anaesthetic drugs

Although screening tests to prevent anaphylaxis during anaesthesia have been advocated, such tests are unlikely to have significant impact on reducing the incidence of anaphylaxis during anaesthesia. This is due to the low prevalence of the disease, the diversity of drugs used in anaesthesia and the incidence of false positive and negative tests. The suggested risk factors of allergy, i.e. atopy, asthma, family history, female sex, previous exposure, vasectomy, use of zinc protamine sulfate insulin and allergy to cosmetics, eggs, fish and non-anaesthetic drugs are not valid. Although all have theoretical or real associations with anaphylaxis during anaesthesia the majority of patients with such a history undergo uneventful anaesthesia. Fruit allergy, anaphylaxis to cephalosporins and penicillin, barbiturate allergy, gelatin allergy and allergy to metabisulphite and eggs require consideration in avoiding particular drugs. The incidence of anaesthetic anaphylaxis can be reduced by avoiding latex exposure in patients with spina bifida or latex allergy, and preventing second reactions in patients with a history of anaphylaxis, or major undiagnosed or undocumented adverse events during anaesthesia. Determining the cause of an adverse event and the drug responsible, and adequately communicating those findings can reduce second reactions. Avoiding neuromuscular blocking drugs (NMBDs) in patients who have reacted to an NMBD, and use of non-intravenous techniques should also reduce the incidence of second reactions. Desensitisation, and blocking with monovalent quaternary ammonium compounds may allow improved safety of NMBDs and pretreatment with antihistamines and corticosteroids may block or ameliorate the severity of reactions, but there is currently little evidence to support their routine use.

Management of a parturient with a history of local anesthetic allergy

IMPLICATIONS

The management of parturients with a strong history of allergy to local anesthetics poses significant challenges to the obstetric anesthesiologist. We recommend that when such patients have a strong desire to receive labor analgesia with local anesthetics, they undergo provocative challenge testing with preservative-free bupivacaine performed in labor and delivery with preparations for emergent cesarean delivery after 24-wk gestation.

A primigravida allegedly allergic to local anaesthetics

Pregnant patients may give a history of allergy to local anaesthetics, but many of these supposed allergies have not been investigated. There is cross-reactivity between the amide local anaesthetics, which are the only group available in the UK for regional analgesia. We report the management of a primigravida who gave a history of allergy to two local anaesthetics, lidocaine and prilocaine. She was admitted to the labour ward at 38 weeks' gestation for challenge testing to the amide local anaesthetic bupivacaine, with full resuscitation and delivery facilities available. The tests proved negative and she was allowed home. She was re-admitted at term in labour and requested epidural analgesia. Epidural bupivacaine with fentanyl was used without incident for labour and forceps delivery. Subsequent allergy testing to lidocaine also proved negative.

The pharmaceuticals and materials used in common spine interventions

Image-guided spine interventions are rapidly increasing in number in the realm of the interventional radiologist. Appropriate selection and understanding of the pharmaceuticals used in these procedures is necessary to minimize complications and maximize successful outcomes.