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

EAACI/ENDA position paper on drug provocation testing

In drug hypersensitivity, drug provocation testing (DPT), also called drug challenge, is the gold standard for investigation. In recent years, risk stratification has become an important tool for adjusting the diagnostic strategy to the perceived risk, whilst still maintaining a high level of safety for the patient. Skin tests are recommended before DPT but may be omitted in low-risk patients. The task force suggests a strict definition of such low-risk patients in children and adults. Based on experience and evidence from studies of allergy to beta-lactam antibiotics, an algorithm on how to adjust DPT to the risk, and when to omit skin tests before DPT, is presented. For other antibiotics, non-steroidal anti-inflammatory drugs and other drugs, skin tests are poorly validated and DPT is frequently necessary. We recommend performing DPT with chemotherapeutics and biologicals to avoid unnecessary desensitization procedures and DPT with skin tests negative contrast media. We suggest DPT with anesthetics only in highly specialized centers. Specifics of DPT to proton pump inhibitors, anticonvulsants and corticosteroids are discussed. This position paper provides general recommendations and guidance on optimizing use of DPT, whilst balancing benefits with patient safety and optimizing the use of the limited available resources.

Local anesthetics allergy in children: Evaluation of diagnostic tests with Real-Life data

BACKGROUND

Local anesthetic (LA) drugs are commonly used in clinical practice to provide effective analgesia, including in dentistry and minor surgical procedures. The perception of a high risk of allergy in daily applications leads to the referral of atopic patients and those with other drug allergies to allergy clinics for the evaluation of allergic reactions to LA. The aim of this study was to determine who should be referred to the allergy clinic for LA allergy testing, assess the frequency of LA allergy in pediatric patients, and identify the negative predictive value of skin tests in diagnosis.

METHODS

January 2017-July 2023, the clinical and laboratory data, as well as the results of drug allergy tests, of patients referred to our pediatric allergy clinic by dentists and physicians performing minor surgical procedures with suspected LA allergy were retrospectively evaluated.

RESULTS

Our study included a total of 153 patients, comprising 84 girls (54.9%) and 69 boys (45.1%), with a mean age of 8.9 (±3.3) years. The most common reason for referral was a history of non-LA drug allergies (n = 66, 43.2%), followed by asthma (n = 25, 16.3%). Hypersensitivity reactions (HRs) with LA were most commonly associated with articaine (n = 7, 4.8%), followed by lidocaine (n = 6, 4.1%). When intradermal tests were evaluated, 17 patients (11.1%) had a positive test result. The positivity for lidocaine was 70.6% (n = 12), and prilocaine was 29.4% (n = 5). Subcutaneous provocation was administered to 109 patients (71.2%), and one patient exhibited local erythema and swelling with prilocaine.

CONCLUSION

Although LA allergy is a rare occurrence, consultations of this nature are frequently requested from allergy clinics in real life. Considering the negative predictive value of skin tests performed with LA drugs, the reaction rate appears to be low in patients with atopy or other drug allergies. It is crucial for all relevant healthcare professionals to be knowledgeable about the appropriate approach to suspected LA allergies to avoid unnecessary tests. To the best of our knowledge, our study is the most comprehensive work in the literature that evaluates the results of diagnostic tests in children referred with a suspicion of LA allergy.

[Drug allergy: Fundamental aspects in diagnosis and treatment.]

BACKGROUND

Any substance used as a treatment for any disease can produce harmful or unpleasant events called adverse drug reactions (ADRs). They are due to inherent biological effects of the drug and are caused by immunological and non-immunological mechanisms.

OBJECTIVES

To describe the immunological mechanisms of hypersensitivity reactions (HSR) to drugs, their epidemiology, risk factors, classification, clinical manifestations, diagnosis, treatment, and prognosis.

METHODS

A review of the most current literature in English and Spanish was carried out, in the main databases, related to the HSR of various drug groups.

RESULTS

This study describes the terms used to define ADRs and HSRs, their classification and clinical manifestations, current diagnostic tools, treatment algorithms and prognosis of the most frequently used medications and with the highest prevalence of reported adverse events.

CONCLUSION

ADRs are a challenging entity, with a complex pathophysiology that has not been fully understood. Its approach requires a careful consideration since not all drugs have validated tests for their diagnosis nor a specific treatment. When indicating the use of any drug, the severity of the disease, the availability of other treatments and the potential risks of developing future adverse events should always be taken into consideration.

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.

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.

Local Anesthesia in Interventional Radiology

Interventional radiology is an evolving field that treats a variety of diseases. Local anesthetics is an important component of pain management during interventional radiologic procedures. It is highly effective and generally safe for routine procedures. However, local anesthetics can be associated with painful initial injection, allergic reactions, and rare but potentially devastating systemic toxicities. Recent evidence has shown that buffered solution and warm local anesthetics may reduce injection discomfort and improve clinical efficacy. Sensible safety practices and prompt recognition/treatment of the systemic toxicity are of paramount importance to provide safe local anesthesia. Interventional radiologists should be familiar with the basic pharmacology, common local anesthetics, optimizing strategies, complications, and management to provide safe and effective local anesthesia for patients.

Risk Factors for Immediate-Type Local Anesthetic Hypersensitivity Reactions in Pediatric Patients: A Retrospective Case-Control Study

Background

Local anesthetics (LA) are relatively safe and rarely cause immediate hypersensitivity reactions. The data on immediate LA hypersensitivity and its risk factors in children are limited.

Aim

To evaluate risk factors of immediate LA hypersensitivity.

Methods

The retrospective case-controlled study included 17 patients with confirmed immediate LA hypersensitivity. For each patient, three age- and gender-matched control subjects were included in the study. LA hypersensitivity was excluded by skin tests and subcutaneous drug provocation tests in all control subjects.

Results

The most common allergic assessment in the patient/control group was for lidocaine (n=5; 29.4%, vs n=23; 45.1%). Suspected LA hypersensitivity reactions were found to be associated with cutaneous manifestations in 14 (82.4%) patients and in 7 (13.7%) of the controls. A history of exposure to local anesthetics twice or more was present in 11 (64.7%) patients vs 6 (11.8%) controls. In conditional regression analysis, repeated LA exposure (≥2) and cutaneous findings were determined as significant risk factors (Odds Ratio [OR]:5.7; 95% Confidence Interval [CI]:1.2–27.1; P=0.029 and (OR:17.3; 95% CI:3.6–82.5; P<0.001, respectively).

Conclusion

Cutaneous manifestations and a history of LA exposure twice or more were predictive factors for LA allergy confirmed by skin test in children.

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.

Characterization of interactions between local anesthetics and histamine H1 receptor by cell membrane chromatography model

Local anesthetic has a wide application in clinical practice. However, angioedema, an adverse reaction caused by local anesthetics, has been reported to be related to histamine H₁ receptor (H₁R). Hence, an effective and practical method for investigating the interaction characteristics between local anesthetics and H₁R is needed. In this work, the competition binding assay and the relative standard method based on H₁R-HEK293/cell membrane chromatography (CMC) were developed to analyze the equilibrium dissociation constant (K_D) values of local anesthetics with H₁R. The activity of drugs toward H₁R was evaluated by intracellular Ca²⁺ imaging assay. Molecular docking was used to verify the interaction modes that occurred at the activate pocket of H₁R protein. Results showed that the local anesthetics can directly occupy histamine binding sites on H₁R, and the K_D values obtained from different CMC methods exhibited positive correlations with each other (p < 0.01). The K_D values of tetracaine, procaine, and lidocaine were much closer to that of histamine than bupivacaine and ropivacaine. This was not only in line with the Ca²⁺ responses in activating H₁R, but also consistent with the same amino acid residues shared with histamine in the H₁R active site. In conclusion, this study provided new insight into the interactions between local anesthetics and H₁R. The H₁R-HEK293/CMC methods developed in this study could be used to evaluate the interaction characteristics of those compounds acting on H₁R.

[Manifestations of allergic reactions occurring at a dental appointment]

OBJECTIVE

To analyze the data of modern scientific literature to conduct a study on identifying the true allergic reaction at a dental appointment.

MATERIAL AND METHODS

The article is based on the study of materials from domestic and foreign research databases eLibrary, PubMed, Cochrane Database Systematic Reviews. The research period is 15 years.

RESULTS

Among dental materials, the most common allergens are local anesthetics, metal alloys, components of composite materials, latex.

CONCLUSION

If allergy is suspected, it is necessary to carefully collect an anamnesis and conduct a clinical examination of the patient with the involvement of specialist doctors, with the recommendation of skin tests and test subcutaneous provocation.

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.

H1R mediates local anesthetic-induced vascular permeability in angioedema

Angioedema may occur during local anesthetic (LA) injection in the perioperative period. Histaminergic angioedema is the most common form of angioedema. It has been reported that LA is a potential exogenous ligand for histamine receptor 1 (H₁R). Whether H₁R participates in LA-induced angioedema is still controversial. By using a constructed H₁R high-expressed cell model, siRNA transfection, pharmacologic means, and genetically modified animal models, here we showed that H₁R mediated LA-induced hyperpermeability. LA with uncycled N-methyl scaffold in the side chain (procaine, tetracaine and lidocaine) had a better strength of drug-H₁R affinity than that for LA with cycled N atom (bupivacaine and ropivacaine) by the molecular docking assay and equilibrium dissociation constant (K_D values) obtained from the cell membrane chromatography (CMC) relative standard method. Procaine, tetracaine, and lidocaine triggered big calcium mobilization in H₁R-HEK293 cells and human umbilical vein endothelial cells (HUVECs) but much weaker in NC-HEK293 cells or H₁R knockdown HUVECs. Besides, the results of transendothelial resistance measurement, paracellular flux assay and immunofluorescence showed that procaine induced H₁R-dependent hyperpermeability, which involved in PLCγ/IP3R/PKC, ERK1/2, Akt signaling pathways, downstream vascular endothelial cadherin (VE-cad) destabilization. Furthermore, H₁R gene knockout prevented paw swelling and vascular leakage caused by procaine, tetracaine, and lidocaine in vivo. This study supported a key role of H₁R in LA-induced angioedema, and suggested that in the design of LA structure, the ring formation of the N-methyl scaffold on the side chain can properly avoid the angioedema.

Drug Hypersensitivity Reactions

Drug hypersensitivity reactions (DHRs) may be classified based on timing (immediate vs delayed), mechanisms, and pattern of clinical manifestations. Management may include selection of alternative, non-cross reactive agents, drug allergy testing, graded challenge and/or desensitization. Immediate skin testing only identifies risk for immediate-type allergic DHR and has a negative predictive value for only a limited number of drugs (eg, penicillin). Desensitization induces a temporary state of tolerance that is maintained only so long as the drug is continued. This article discusses special considerations about antibiotics, angiotensin-converting enzyme inhibitors, anesthetic agents, aspirin and nonsteroidal antiinflammatory drugs, radiocontrast media, and chemotherapeutic agents.

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.

[Dental care for patients at risk of adverse reaction to local anesthetics]

The study comprised 53 patients with side effect history to local anesthetics. The reasons for the occurrence of adverse reactions to local anesthetics was analyzed, and the frequency of their occurrence in dental practice was studied. It was found that in most patients (85%) with 'allergic reactions' to local anesthetics the diagnosis was unreasonable and incompetent. In most cases psychosomatic reactions were mistaken for an immediate allergic reaction. The prevalence of adverse reactions to local anesthetics was 1 case per 448 injections (1:448), true allergic reactions was documented in 0.1% cases.

The Journal of Allergy and Clinical Immunology: In Practice 2018 Highlights

A large number of clinically impactful studies and reviews were published in this journal in 2018. This article provides highlights of the original research published in 2018 issues of The Journal of Allergy and Clinical Immunolgy: In Practice on the subjects of anaphylaxis, asthma, dermatitis, drug allergy, eosinophilic disorders, food allergy, immune deficiency, rhinitis, and urticaria/angioedema and mast cell disorders. Within each topic, practical aspects of diagnosis and management are emphasized. Treatments discussed include lifestyle modifications, allergen avoidance therapy, positive and negative effects of pharmacologic therapy, and various forms of immunologic and desensitization management. We hope this review will help readers consolidate and use this extensive and practical knowledge for the benefit of patients.