EAACI position paper on how to classify cutaneous manifestations of drug hypersensitivity

Direct oral provocation test with beta-lactams in Brazilian children and adolescents

OBJECTIVE

Beta-lactam (BL) allergy is considered a public health issue worldwide. To date, there is no consistent data on the direct Oral Provocation Test (OPT) for BL in Brazilian children and adolescents. This study's main objective is to describe the safety profile of direct OPT in this population.

METHOD

A cross-sectional study was conducted with patients aged 1 to 17 years with a history of mild immediate or delayed reactions to penicillin. The European Network of Drug Allergy (ENDA) questionnaire was used. The authors performed OPTs with amoxicillin over five days. Continuous variables were described using their means and standard deviations. Bivariate analysis between test positivity and other study variables was performed using the Chi-square test, odds ratio, and their respective 95 % confidence intervals (CI 95 %). A p-value < 0.05 was considered significant.

RESULTS

In total, 54 OPTs were performed, four were positive (7.5 %) and one was considered inconclusive. All reactors were boys and had delayed reactions, with no severe reactions, and three showed symptoms on the first day of testing.

CONCLUSION

>90 % of the sample was delabeled as allergic to BL. There were no severe reactions, confirming the safety of direct OPT in this age group. Among the reactors, 3 patients presented symptoms on the first day of testing before receiving the second dose and one had symptoms on 5 days, indicating that further studies are needed on the optimal duration of the OPT.

Decoding Beta-Lactam Cross-Reactivity - Longitudinal Patch Testing From 2000 to 2022

INTRODUCTION

Patients with non-immediate hypersensitivity to beta-lactam antibiotics (βL) often avoid all βL, with limitations for future therapy.

OBJECTIVES

Assess cross-reactivity between βL in non-immediate cutaneous adverse drug reactions (ni-CADRs).

METHODS

Retrospective analysis (2000-2022) of patients with suspected ni-CADR with βL as a possible culprit who underwent patch testing (PT) with an extended antibiotic series (10% pet., Chemotechnique Diagnostics or prepared in-house) according to European Society of Contact Dermatitis (ESCD) recommendations. Fisher exact test was used with a significance of 0.05 corrected for multiple testing; positive associations were quantified with odds ratio (OR) with 95% confidence interval (CI).

RESULTS

Four hundred and fourteen patients (270 female/144 male; age 52 ± 19 years) were included, mostly with maculopapular exanthema (367; 89%), drug reaction with eosinophilia and systemic symptoms (DRESS) (22; 5%) and acute generalised exanthematous pustulosis (AGEP) (12; 3%). Eighty-six patients (21%) had positive results to at least one drug. Fifty-eight patients (14%) had 110 positive results to βL, mostly amoxicillin (33). Co-reactivity within penicillins was almost universal, including piperacillin with other penicillins (p = 0.007; OR 25; CI 3-56). There was co-reactivity to aminopenicillins and aminocephalosporins (p = 0.006; OR 33; CI 4-74) and within the cephalosporin subclass, including between aminocephalosporins and non-aminocephalosporins. Within carbapenems, 1 patient reacted to meropenem and ertapenem, with no extension to imipenem, as confirmed with a provocation test. Two patients reacted both to ceftriaxone and meropenem (p = 0.013; OR: 68; CI:15-612).

CONCLUSION

PT is useful to confirm a probable culprit in ni-CADR to βL. Co-reactivity, interpreted mostly as cross-reactivity, occurred within cephalosporin and, particularly, with penicillin subclasses, including between piperacillin-tazobactam and remaining penicillins, which has seldom been described. There was no association between penicillins and cephalosporins as a whole, except between aminopenicillins and aminocephalosporins, attributable to a similar lateral chain amino group. We found an unexpected association between meropenem and ceftriaxone, probably a concomitant sensitization.

Incidence and Factors Associated with Self-Reported Skin Symptoms of Allergic Reactions to COVID-19 Vaccines

Background: Few reports exist regarding the incidence and factors associated with allergic reactions to COVID-19 vaccines during post-marketing surveillance, especially for inactivated whole virus or viral vector vaccines. We aimed to determine the incidence and factors associated with self-reported allergic reactions to COVID-19 vaccines in the Thai population. Methods: A cross-sectional case-control study was conducted via telephone-based interviews. Cases were defined as physician-confirmed, self-reported vaccine recipients diagnosed with non-severe immediate allergic reactions, anaphylaxis, or delayed allergic reactions. Controls were randomly sampled from vaccinated individuals who reported no adverse events and were matched by the type of vaccine (1 case:2 controls). Demographic information and the history of atopic diseases were collected in both groups. Conditional logistic regression analysis was used to explore associated factors. Results: Among 215,079 vaccine doses administered, the incidence of self-reported skin symptoms of allergic reactions was 1821 events (0.85%). The risk factors for allergic reactions included age < 60 years (aOR 3.53; 95% CI:1.43-8.70; p = 0.006), female sex (aOR 8.33; 95% CI: 4.35-15.94; p < 0.001), a personal history of allergic rhinitis (aOR 4.32; 95% CI: 2.43-7.69; p < 0.001), atopic dermatitis (aOR 4.27; 95% CI: 1.74-10.47; p = 0.002), food allergies (aOR 6.53; 95% CI: 2.42-17.61; p < 0.001), and a family history of allergic disease (aOR 2.14; 95% CI: 1.12-4.08; p = 0.021). Conclusions: COVID-19 vaccines showed a low incidence of self-reported allergic reactions, which were more likely to occur in younger individuals, females, and those with a history of atopic diseases.

Penicillin allergy management strategies relevant for clinical practice - a narrative review

Penicillin allergy is the most commonly reported drug allergy, with prevalence rates ranging from 6% to 31% across various populations and geographic areas. The penicillin allergy label is linked to higher mortality and morbidity rates, extended hospital stays, increased readmission rates, and a greater reliance on second-line antibiotics. Research indicates that nearly 99% of those labeled as penicillin-allergic can tolerate the drug. However, alternative antibiotics are often prescribed without confirming the allergy, largely due to legal concerns regarding re-exposure. Even when a negative challenge test is conducted, non-allergist providers may remain hesitant to reintroduce penicillins. To address the considerable gap between reported and actual penicillin allergies, as well as to ensure the prompt use of penicillins by non-allergists, various management strategies have emerged in recent years. Although several comprehensive reviews have examined these strategies, selecting and applying the most suitable for routine practice is difficult. This narrative review focuses on the most relevant data regarding the efficiency of key penicillin allergy risk-assessment tools, particularly those of clinical significance, and discusses their readiness for implementation in non-allergist settings.

Rare delayed hypersensitivity reactions to contrast media: Severe cutaneous adverse reactions

The risk of developing a severe delayed cutaneous reaction (SCAR) is very low following iodine-based contrast medium (ICM) administration and extremely low following gadolinium-based contrast agent (GBCA) administration. However, SCAR can be very severe and potentially life-threatening. It is crucial for the imaging physician to recognize danger signals: bullous skin eruption, skin erosion and detachment, mucosal involvement, systemic symptoms, and laboratory abnormalities. Patients suspected of having a SCAR should be urgently referred to a drug allergy specialist or dermatologist. To prevent recurrence, consider exploring alternative imaging modalities and avoid administering the same type of contrast medium involved: if the culprit is a ICM, avoid all ICM and if the culprit is a GBCA, avoid all GBCA. In an allergy centre with experience in SCAR evaluation a careful allergologic analysis may be performed safely several months after the patient has recovered from SCAR. However, allergologic analysis is challenging due to the lack of reliable in vitro diagnostic tests and the risks of in vivo diagnostic tests, particularly drug provocation tests.

Local infiltration anesthesia with high dose ropivacaine and dexmedetomidine in major knee surgery is safe

BACKGROUND

The role of local infiltration anesthesia (LIA) in knee surgery is significant. LIA can be more potent than a nerve block, but without the downsides. A wide range of agents are used for LIA, including some off-label medications such as dexmedetomidine and ropivacaine. Dexmedetomidine has recently received attention for decreasing demand for anesthetic agents and prolonged effect of anesthesia. The purpose of this study was to demonstrate safety of dexmedetomidine and ropivacaine as LIA.

METHODS

This is a retrospective analysis of 200 patients receiving 300 mg of ropivacaine, 100 µg of dexmedetomidine and 10 mL of saline solution as LIA. Both agents are off-label for this use. The LIA applied prior to skin closure as a pertiarticular block. Major knee surgery was defined as ligament reconstruction of at least one ligament, fracture of the femur and the tibia, knee replacement and osteotomy. We evaluated short-term major side-effects of these agents, and evaluated 30-day complications.

RESULTS

Included were 77 arthroplasties, 10 fracture fixations, 19 osteotomies, 55 primary and revision ACL, 10 isolated medial patellar femoral ligament reconstructions, 2 ACLs combined with a partial knee arthroplasty, 4 cartilage transplantations and 23 multiligament knee reconstructions. We observed one transitory discoloration after an ACL reconstruction that disappeared by the 48 h mark. We had no 30-day superficial or deep infections. Cardiac or allergic reactions were not observed.

CONCLUSIONS

LIA in a combination of single high-dose ropivacaine and dexmedetomidine is safe in knee surgery. Further studies evaluating pain relief with this LIA combination are needed.

Patch testing in non-immediate hypersensitivity to cotrimoxazole: Is it useful?

BACKGROUND

Existing literature has questioned the sensitivity of patch testing (PT) with cotrimoxazole (CTX) in the study of drug hypersensitivity.

OBJECTIVES

Assess the sensitivity of PT with CTX in non-immediate cutaneous adverse drug reactions (CADR).

PATIENTS/MATERIALS/METHODS

Retrospective analysis (2000-2022) of PT with an antibiotic series including CTX 10% pet (Chemotechnique Diagnostics©) performed according to ESCD guidelines in patients with suspected non-immediate CADR reactions to CTX. Some patients were additionally tested with in-house preparations of CTX from Bactrim DS® tablets at 10% in pet or water and trimethoprim 10% pet (Laboratórios Edol©).

RESULTS

Sixty-four patients (48F/16M; mean age 47 ± 18) were included, mostly with maculopapular exanthema (51, 80%). Notably, CTX was sole suspect in 24 patients. There was no positive reaction to CTX at 10% from Chemotechnique or Bactrim DS® tablets prepared at 10% pet for patch testing. One patient reacted exclusively to trimethoprim with 1+ reaction. Two patients had a faint reaction (1+) only with the powder of Bactrim DS® tablets in water at D2, but as the reactions faded completely in 24 or 48 h, they were interpreted as irritant non-specific reactions.

CONCLUSION

These findings suggest that patch testing may lack sufficient sensitivity to diagnose CTX-induced non-immediate CADR. Therefore, clinicians should be cautious interpreting CTX patch test results.

Acute generalized exanthematous pustulosis: European expert consensus for diagnosis and management

Acute generalized exanthematous pustulosis (AGEP) is a rare, usually drug-induced, acute pustular rash. Despite the lack of strong data supporting the effectiveness of topical or systemic corticosteroids in this drug reaction, they are widely used. More generally, there is no consensus on the diagnostic modalities and the management of patients with AGEP. We aimed to provide European expert recommendations for the diagnosis and management or patients with AGEP. Members of the ToxiTEN group of the European Reference Network (ERN)-skin, all dermatologists and/or allergologists with expertise in drug reactions, elaborated these recommendations based on their own experience and on a review of the literature. Recommendations were separated into the following categories: professionals involved, assessment of the diagnosis of AGEP, management of the patient and allergological work-up after the acute phase. Consensus was obtained among experts for the list of professionals involved for the diagnosis and management of AGEP, including the minimum diagnostic work-up, the setting of management, the treatments, the modalities and the timing of allergological work-up and follow-up. European experts in drug allergies propose herein consensus on the diagnosis and management of patients with AGEP. A multidisciplinary approach is warranted, including dermatologists, allergologists and pharmacovigilance services.

In vitro diagnostics of drug allergies

In vitro diagnostics for drug hypersensitivity reactions distinguish between serological and cellular-based tests. A serological test used for the diagnosis of immediate type reactions is the detection of specific IgE antibodies. The cellular tests include the basophil activation test for immediate type reactions and the lymphocyte transformation test, which is mainly used to detect delayed type hypersensitivity reactions. Further cellular-based tests are the CAST-ELISA and the mast cell activation test. None of the above-mentioned tests can definitively exclude an allergy if the result is negative. In addition, it is important to note that even a positive test result is not necessarily associated with an allergy but has to be interpreted in the clinical context.

Symmetrical Drug-Related Intertriginous and Flexural Exanthema With Amoxicillin: Presenting a Flare-Up Phenomenon

This case report describes a 40-year-old male patient who developed symmetrical drug-related intertriginous and flexural exanthema after taking amoxicillin. Initial allergy testing showed negative intradermal tests, but subsequent drug provocation tests with amoxicillin and penicillin were positive, indicating cross-reactivity between these β-lactam antibiotics. Notably, following the final provocation test, the intradermal test with penicillin turned positive, demonstrating a flare-up phenomenon. The findings highlight the importance of thorough allergy evaluations, including drug provocation testing, to guide safe antibiotic treatment.

Patch tests in non-immediate cutaneous adverse drug reactions: Late readings on Day 4 is more sensitive than on Day 3

BACKGROUND

Patch tests (PTs) are recommended to identify the culprit drug in non-immediate cutaneous adverse drug reactions (NICADRs). We recently reported that, in patients with NICADRs, a unique reading of PTs at day (D)2 compared with an additional second late reading at D4 missed almost half (45.3%) of the positive PTs.

OBJECTIVES

To assess the change in sensitivity of the PT reading on D4 compared with the reading on D3.

METHODS

We performed a retrospective (July 2020-June 2023) monocentric study of patients who had PTs with two readings for a NICADR. We compared reading on D3 and the second reading on D4 for the suspected drug (primary outcome) and for the related drugs tested simultaneously (secondary outcome).

RESULTS

During the study period, 249 patients underwent patch testing with D3 and D4 readings. Regarding the primary outcome, the first reading at D3 was positive for 13.7% of patients, and the reading at D4 for 24.9% of patients (p < 0.0001). Regarding the secondary outcome, only 9.6% of patients had all their positive PT at D3 compared with 24.9% of patients at D4 (p < 0.0001). Considering the evaluated drug classes, no statistical difference was observed. However, we highlight that D3 reading detected all positive carbamazepine PTs (n = 3) while positive clindamycin PTs (n = 4) were identified only with the help of the second reading on D4.

CONCLUSION

This study showed that, an additional D4 reading compared with a single D3 reading enhanced the sensitivity of PTs to identify culprit drugs and related. Further studies should replicate these findings and evaluate the medico-economic balance and safety of a single reading of PTs on D4.

Pathophysiology of drug hypersensitivity

Drug hypersensitivity reactions (DHRs) are type B adverse drug reactions (ADRs) traditionally defined as unpredictable, dose independent and not related to the drug pharmacology. DHRs, also called drug allergy if the immune system involvement is confirmed, represent around one-sixth of all ADRs and can cause major clinical problems due to their vague clinical presentation and irregular time course. Understanding the underlying pathophysiology of DHRs is very important for their diagnosis and management. Multiple layers of evidence exist pointing to the involvement of the immune system in DHRs. Recent data have led to a paradigm shift in our understanding of the exact pathophysiology of these reactions. Numerous hypotheses proposing explanation on how a low molecular weight drug molecule can elicit an immune reaction have been proposed. In addition to the classical "hapten" hypothesis, the reactive metabolite hypothesis, the pharmacological interaction with the immune system (p-i) concept, the danger/injury hypothesis and the altered peptide repertoire hypothesis have been proposed. We here introduce the inflammasome activation hypothesis and the cross-reactivity hypothesis as additional models explaining the pathophysiology of DHRs. Available data supporting these hypotheses are briefly summarized and discussed. We also introduced the cross-reactivity model, which may provide a platform to appreciate the potential role played by other factors leading to the activation of the immune system. We believe that although the drug in question could be the trigger of the reaction, the components of the immune system mediating the reaction do not act in isolation but rather are affected by the proinflammatory milieu occurring at the time of the reaction. This review attempts to summarize the available evidence to further illustrate the pathophysiology of DHRs.

Biodegradable Mesoporous Organosilica-Based Nanostabilizer Targeting Mast Cells for Long-Term Treatment of Allergic Diseases

Allergic diseases are immune system dysfunctions mediated by mast cell (MC) activation stimulated by specific allergens. However, current small molecular MC stabilizers for allergic disease prevention often require multiple doses over a long period of time and are associated with serious side effects. Herein, we develop a diselenide-bridged mesoporous silica nanostabilizer, proving that it could specifically target sensitized MCs via the recognition of IgE aptamer and IgE. Meantime, the IgE aptamer can also mitigate allergic reactions by preventing re-exposure of allergens from the surface of sensitized MCs. Furthermore, the diselenide-bridged scaffold can be reduced by the intracellular excessive ROS, subsequently achieving redox homeostasis via ROS depletion. Finally, the precise release of small molecular MC stabilizers along with the biodegradation of nanocarrier can stabilize the membranes of MCs. In vivo assays in passive cutaneous anaphylactic (PCA) and allergic rhinitis (AR) mice indicated that our current strategy further endowed it with a high efficacy, long-term therapeutic time window, as well as negligible inflammatory side effects for allergic diseases, offering a promising therapeutic strategy for the clinical generalization of allergic diseases.

Protein Haptenation and Its Role in Allergy

Humans are exposed to numerous electrophilic chemicals either as medicines, in the workplace, in nature, or through use of many common cosmetic and household products. Covalent modification of human proteins by such chemicals, or protein haptenation, is a common occurrence in cells and may result in generation of antigenic species, leading to development of hypersensitivity reactions. Ranging in severity of symptoms from local cutaneous reactions and rhinitis to potentially life-threatening anaphylaxis and severe hypersensitivity reactions such as Stephen-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN), all these reactions have the same Molecular Initiating Event (MIE), i.e. haptenation. However, not all individuals who are exposed to electrophilic chemicals develop symptoms of hypersensitivity. In the present review, we examine common chemistry behind the haptenation reactions leading to formation of neoantigens. We explore simple reactions involving single molecule additions to a nucleophilic side chain of proteins and complex reactions involving multiple electrophilic centers on a single molecule or involving more than one electrophilic molecule as well as the generation of reactive molecules from the interaction with cellular detoxification mechanisms. Besides generation of antigenic species and enabling activation of the immune system, we explore additional events which result directly from the presence of electrophilic chemicals in cells, including activation of key defense mechanisms and immediate consequences of those reactions, and explore their potential effects. We discuss the factors that work in concert with haptenation leading to the development of hypersensitivity reactions and those that may act to prevent it from developing. We also review the potential harnessing of the specificity of haptenation in the design of potent covalent therapeutic inhibitors.

Knowledge mapping and global trends of drug hypersensitivity from 2013 to 2023: A bibliometric analysis

BACKGROUND

Drug hypersensitivity is a major global public health issue with a significant increase in prevalence in populations. Here, we provide a deep insight into the frontier hotspot and future direction in the field of drug hypersensitivity.

METHODS

A knowledge map is portrayed based on publications related to drug hypersensitivity from Web of Science Core Collection using CiteSpace. Co-occurrence relationships of countries, institutes, authors, journals, references, and keywords are constructed. According to the co-occurrence relationships, hotspots and future trends are overviewed.

RESULTS

The United States ranked first in the world and China with the second highest publications was the only developing country. Torres, Mayorga, and Blanca were highly productive authors. Harvard University was the institution with the most research publications. Keywords co-occurrence analysis suggested applications in emerging causes, potential mechanisms, and clinical diagnosis as the research hotspots and development frontiers.

CONCLUSION

Research on drug hypersensitivity is in a rapid development stage and an emerging trend in reports of anaphylaxis to polyethylene glycols is identified. Developing algorithms for understanding the standardization process of culprit drugs, clinical manifestations, and diagnostic methods will be the focus of future direction. In addition, a better understanding of the mechanisms to culprit drugs with immunological precise phenotypic definitions and high-throughput platforms is needed.

Drug-induced hypersensitivity reactions in a Lebanese outpatient population: A decade-long retrospective analysis (2012-2021)

Background

Drug hypersensitivity reactions (DHRs) are becoming more common as a result of increasing prevalence and case complexity. Allergists and clinical immunologists worldwide are challenged daily to adequately diagnose and manage these reactions. Data in the literature regarding DHR outpatient consultations are scarce worldwide, limited in the Middle East, and currently unavailable in Lebanon.

Objective

This retrospective study aimed to evaluate the characteristics of all reported DHRs over 10 years in a tertiary-care allergy clinic in Lebanon.

Methods

We conducted a decade-long (2012-21) retrospective analysis of the archived medical records of patients with a history of DHRs. Demographics, clinical history, diagnostic tools, and characteristics of the DHRs were collected and analyzed.

Results

A total of 758 patients experienced DHRs to therapeutic molecules provided for ambulatory care. Our results identified 72 medications. The most frequently implicated drug classes included β-lactam antibiotics (53.8%), followed closely by nonsteroidal anti-inflammatory drugs (48.9%). Of the 758 patients, 32.6% reported DHRs to multiple molecules, and 11.8% reported concomitant DHRs to 1 or several molecules provided in the perioperative setting. Of those, opioids and neuromuscular blocking agents were the 2 most common therapeutic classes. Furthermore, we evaluated the cross-reactivity between molecules of the same class. In neuromuscular blocking agents, rocuronium and cisatracurium were the most commonly cross-reactive, and for opioids, the most common association we recorded was with morphine and pethidine.

Conclusion

Our findings constitute the first step toward a more comprehensive evaluation of the clinical characteristics of DHRs in Lebanon.

Immediate Reaction to Propranolol: An Extremely Rare but Important Condition. A Case Report

INTRODUCTION

Beta-blockers involve a group of drugs widely used nowadays. Propranolol was the first beta-blocker available in the market. It is the most prescribed first-generation betablocker and is commonly used. Beta-blocker allergy is extremely unusual. Only an isolated case of an urticaria reaction to propranolol has been published in 1975.

CASE PRESENTATION

We present a 44-year-old man. In 2016, he was treated with a daily dose of 5 mg of propranolol prescribed for a diagnosis of essential tremor. On the third day of medical treatment, he experienced an episode of generalized urticaria directly related to the administration of propranolol. He continued with his habitual treatment and he had no other urticaria episodes. A drug provocation test was carried out with gradually increasing doses of the culprit drug. Thirty minutes after a total cumulative dose of 5 mg, the patient had several hives on the chest, abdominal region and arms. Two weeks later, a new drug provocation test was performed to bisoprolol as an alternative beta-blocker, with good tolerance.

CONCLUSION

We describe a new case of urticaria secondary to propranolol, presenting as an immediate hypersensitivity reaction. Bisoprolol has been succesfully proved to be a safe option. Bisoprolol is a second-generation beta-blocker, it is available and commercialized worldwide, which makes it a good alternative.

Different Patterns of Response in Hypersensitivity Reactions to Arylpropionic Acid Derivatives

BACKGROUND

Ibuprofen and other arylpropionic acid derivatives (APs) are among the most consumed nonsteroidal anti-inflammatory drugs worldwide at all age ranges; however, little is known about drug hypersensitivity reactions (DHRs) they induce.

OBJECTIVE

To characterize in detail patients reporting DHRs to APs.

METHODS

We prospectively evaluated patients with symptoms suggestive of AP-DHRs and analyzed their clinical characteristics, reported reactions, and diagnostic approaches.

RESULTS

Six hundred sixty-two patients confirmed as hypersensitive to APs were included: 489 with cross-reactive reactions (CRs) (73.86%) and 173 with selective reactions (SRs) (26.13%). The percentage of subjects reporting reactions to ibuprofen and dexketoprofen was higher in CRs (P = .005 and P = .01, respectively), whereas naproxen and ketoprofen were more frequently involved in SRs (P = .0002 and P = .00001, respectively). The most frequent symptoms induced by ibuprofen, dexketoprofen, and naproxen were isolated angioedema and urticaria, combined or not with angioedema in both CRs and SRs. The result of nasal provocation test with lysine acetylsalicylate was positive in 156 cases (77.14% in patients showing exclusively respiratory symptoms, and in 68.18% of those with both cutaneous and respiratory involvement). To confirm diagnosis, drug provocation test with acetylsalicylic acid was required in 246 CR patients (50.3%), whereas in 28 SR patients (16.18%) drug provocation test with the culprit AP was required.

CONCLUSIONS

Skin is the organ most commonly involved in AP-DHRs, with ibuprofen and dexketoprofen inducing most frequently CRs, and naproxen and ketoprofen SRs. More studies are necessary to clarify the underlying mechanism in DHRs induced by APs.

Drug Allergy in Children: Adverse Reactions after Skin Testing

INTRODUCTION

Skin tests are one of the most widely used diagnostic tools for suspected drug allergies in children. Studies on systemic reactions occurring during skin testing with allergens have mostly been conducted in pediatric and adult patient groups together. However, data on adverse reactions including allergic reactions after drug skin tests in children are scarce. It is aimed to determine the adverse reactions after skin test in children with suspected drug allergy.

METHODS

Patients who underwent a drug skin test due to the suspicion of drug allergy between May 2017 and June 2020 were evaluated, retrospectively. Data about adverse reactions seen after skin testing at the testing area in the clinic were analyzed.

RESULTS

The study included 1,073 children (585 [54.5%] boys and 488 [45.5%] girls) with a median age of 7.5 years. A total of 12 (1.1%) reactions were detected after skin testing, and 4 (0.4%) of them were allergic reactions. Of the allergic reactions, three were anaphylaxis and one was urticaria. Two of the reactions (1 anaphylaxis and 1 urticaria) were detected after the skin prick test and the remaining 2 were detected after intradermal test. Three of the nonallergic reactions were considered as vasovagal reactions and seven were considered as nonspecific and anxiety-related reactions.

CONCLUSION

Although drug skin tests were generally well-tolerated and adverse reactions were rare, severe allergic reactions including anaphylaxis may ensue. Skin tests should be necessarily performed in clinical settings in experienced centers.

Prevalence of Trimethoprim-Sulfamethoxazole Adverse Reaction Mislabelling in Australia

INTRODUCTION

Trimethoprim-sulfamethoxazole (TMP-SMX) is an important antibiotic, with the most compelling indications for Pneumocystis jirovecii pneumonia prophylaxis and methicillin-resistant Staphylococcus aureus treatment. Previous adverse reactions (AR) to TMP-SMX may limit the usability of TMP-SMX. Electronic medical record (EMR) of AR for other antibiotics has previously been shown to be inaccurate; however, the extent to which this occurs for TMP-SMX is unknown.

METHODS

A multi-centre retrospective observational study was conducted for consecutive inpatient admissions over a 2.5-year period commencing 2020. Adverse reactions to TMP-SMX recorded in the EMR were collected and reviewed by two independent medical officers using pre-defined expert criteria for the classification of allergies and intolerances.

RESULTS

TMP-SMX AR were present in the EMR of 759 individuals (prevalence 0.6%). The majority were labelled as allergy (725, 95.5%) rather than intolerance (34, 4.5%). Most common AR were rash, vomiting, and swelling. When classified against the gold-standard expert criteria, there were 437 allergies (57.6%) and 159 intolerances (21.0%). Overall, the number of incorrect EMR AR labels was 133/759 (17.5%). Both medical and surgical specialties had significant numbers of patients with TMP-SMX AR labels and incorrectly classified EMR AR labels.

CONCLUSION

TMP-SMX AR labels affect inpatients admitted under multiple specialty units. The user-entered categorization as allergy or intolerance labels in EMRs are frequently used incorrectly. These incorrect labels may inappropriately contraindicate the use of TMP-SMX, and formal evaluation of TMP-SMX ARs with immunological assessment and relabelling where appropriate may increase the use of this agent.

Athena: Speciality Certificate Examination case for general dermatology and dermatology in primary health care

A 62-year-old man was referred to the emergency department with a 6-day history of a progressive pustular eruption; he had commenced ceftriaxone to treat suspected facial cellulitis 2 days prior. He had no significant past medical or dermatological history. This is a case of a rare severe cutaneous adverse reaction to a prescribed drug.

Aspirin-induced urticaria in a recently diagnosed ischemic stroke patient: A case report and literature review

Key Clinical Message

NSAIDs may be rare but an important cause of urticarial which should not be missed.

Abstract

The aspirin and urticaria correlation has not been fully understood. The pharmacological inference is suspected to be the diversion of arachidonic acid metabolism. Aspirin sensitivity can aggravate preexisting chronic urticaria and in some instances causes acute urticaria. We report a case of a 53-year-old male, recently diagnosed with a stroke, who presented with complaints of multiple rashes over the trunk and upper extremities with aspirin. NSAIDs induced urticarial are usually neglected by physicians during diagnosis.

Stevens-Johnson Syndrome Induced by Herbal Kadha

Stevens-Johnson syndrome (SJS) is a dreaded hypersensitivity reaction and a rare immune disorder. We present a Stevens-Johnson syndrome induced by herbal kadha, which may be the first case. A ten-year-old boy presented with massive sloughing, redness, oedematous skin, an oral ulcer, and an inability to feed or drink for two days. The present symptoms started after 12 hours of consuming herbal Kadha, given by a private practitioner in clinics where he was treated for fever. After not responding to earlier treatment, the patient was referred to the present Institute. The patient had a history of seizure disorder and had been on tablet phenytoin for seven months with no history of adverse reactions to it. He was treated in the intensive care unit. Fortunately, he responded to treatment and recovered fully. He received treatment in the form of immunoglobulin and steroids. Phenytoin and herbal kadha were withdrawn, and Clobazam was continued. Natural herbal medicines can develop severe adverse effects. Physicians should remain aware that drug interactions can likely be seen with drugs with a narrow therapeutic index combined with herbal preparations. Clinicians should do more research on the interaction between herbal and prescription medications.

Photodistributed Stevens-Johnson syndrome and toxic epidermal necrolysis: a systematic review and proposal for a new diagnostic classification

BACKGROUND

Ultraviolet radiation (UVR) exposure is commonly reported as a risk factor for Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN). However, minimal evaluation of photo-induced SJS/TEN has been conducted. Thus, this review identifies all cases of SJS/TEN that are linked to an acute exposure of UVR and outlines the unifying characteristics of these cases. Furthermore, the theoretical pathogenesis, differential diagnoses, and proposed diagnostic criteria are defined.

METHODS

PubMed, Google Scholar, and other databases and websites were searched from inception to September 2021 to identify studies that met inclusion criteria. The following keywords were utilized: "Stevens-Johnson syndrome" and "toxic epidermal necrolysis" with "ultraviolet," "photodistributed," "photo-induced," "photosensitivity," and "photo." One reviewer assessed study characteristics, with confirmation by a second. The risk of bias was assessed independently by another.

RESULTS

Thirteen patient cases were identified, all reporting ultraviolet radiation prior to rash onset and an underlying causal drug. Case classifications included 7/13 SJS and 6/13 TEN. All cases described the rash as photodistributed with UVR exposure prior to rash onset (delay of 1-3 days) and a causal drug. 10 cases provided evidence that the photodistributed rash lacked linear demarcation (as in a sunburn) with satellite target-like lesions. No cases described a flu-like prodrome.

DISCUSSION

Mucositis, palmar and plantar rash, a positive Nikolsky sign, and a prolonged disease course can help distinguish from photosensitive reactions, while a negative direct immunofluorescence test is important to distinguish from other photo-induced disorders.

CONCLUSION

Physicians should be aware that UVR may precipitate SJS/TEN in patients taking susceptible drugs. After a 24-h delay from UVR exposure, a non-distinct, photodistributed rash appears with no flu-like prodrome and progresses for at least 48 h to include vesiculobullous eruptions and mucous membrane involvement. Photodistributed SJS/TEN appears to be photo-drug-induced with a unique onset and rash presentation that should be recognized as a distinct diagnosis.

[Diagnostics of drug allergies and intolerances]

The prevalence of hypersensitivity reactions to drugs is increasing. Currently, this affects more than 7% of the world population. Nonsteroidal anti-inflammatory drugs (NSAID) and beta-lactam antibiotics (BLA) are by far the most common pharmaceutical preparations involved in hypersensitivity reactions to drugs. Misdiagnoses are frequent and BLA allergies present a danger that can lead to adverse health outcomes. Therefore, delabeling (exclusion of a suspected diagnosis) is paramount for those affected. Following the occurrence of uncomplicated maculopapular exanthemas, outpatient oral drug provocation can be safely considered in children without prior skin tests. Immediate perioperative reactions are rare. The approach to studying these complex reactions requires collaboration between allergologists and anesthesiologists to provide the best possible care for these patients.

Updates on the immunopathology and genomics of severe cutaneous adverse drug reactions

Severe cutaneous adverse reactions (SCARs) such as Stevens-Johnson syndrome, toxic epidermal necrolysis (SJS/TEN), and drug reaction with eosinophilia and systemic symptoms (DRESS)/drug-induced hypersensitivity syndrome (DIHS) cause significant morbidity and mortality and impede new drug development. HLA class I associations with SJS/TEN and drug reaction with eosinophilia and systemic symptoms/drug-induced hypersensitivity syndrome have aided preventive efforts and provided insights into immunopathogenesis. In SJS/TEN, HLA class I-restricted oligoclonal CD8+ T-cell responses occur at the tissue level. However, specific HLA risk allele(s) and antigens driving this response have not been identified for most drugs. HLA risk alleles also have incomplete positive and negative predictive values, making truly comprehensive screening currently challenging. Although, there have been key paradigm shifts in knowledge regarding drug hypersensitivity, there are still many open and unanswered questions about SCAR immunopathogenesis, as well as genetic and environmental risk. In addition to understanding the cellular and molecular basis of SCAR at the single-cell level, identification of the MHC-restricted drug-reactive self- or viral peptides driving the hypersensitivity reaction will also be critical to advancing premarketing strategies to predict risk at an individual and drug level. This will also enable identification of biologic markers for earlier diagnosis and accurate prognosis, as well as drug causality and targeted therapeutics.

Utility and Safety of Skin Tests in Drug Reaction With Eosinophilia and Systemic Symptoms (DRESS): A Systematic Review

BACKGROUND

Determination of culprit drug in drug reaction with eosinophilia and systemic symptoms (DRESS) is crucial. Skin tests have been used, although it remains unclear how sensitive these are.

OBJECTIVE

To determine the value of skin tests in the assessment of drug causality in DRESS.

METHODS

A systematic literature search was conducted for publications from 1996 onward of skin tests (skin prick test = SPT, patch test = PT, intradermal test = IDT) performed in clearly defined DRESS cases. Outcomes of testing, drug culpability assessments, and challenge test data were extracted.

RESULTS

A total of 17 articles met inclusion criteria. In 290 patients with DRESS, patch testing was most frequent (PT = 97.2% [n = 282], IDT = 12.4% [n = 36], SPT = 3.1% [n = 9]). Positive results were noted in 58.4% (n = 160 of 282) of PTs, 66.5% of IDTs, and 25% of SPTs. When confidence of drug causality was high (n = 73 of 194), testing did not correlate well with clinical suspicion: PTs, 37.6%; IDTs, 36.5%. Direct comparison of skin testing with provocation testing (n = 12) showed 83.3% correlation. Positive IDT results were reported in 8 negative PT cases.

CONCLUSIONS

Skin tests, particularly PTs and IDTs, have been reported as tools for diagnosis of causal drugs in DRESS. Heterogeneity in methodology, results analysis, and reporting of cohorts make meta-analysis to determine sensitivity and specificity of published literature impossible and highlight weaknesses in the field. We propose that international collaboration is essential to harmonize the methodology and reporting measures from hypersensitivity testing studies in larger cohorts.

Delayed Drug Hypersensitivity Reactions: Molecular Recognition, Genetic Susceptibility, and Immune Mediators

Drug hypersensitivity reactions are classified into immediate and delayed types, according to the onset time. In contrast to the immediate type, delayed drug hypersensitivity mainly involves T lymphocyte recognition of the drug antigens and cell activation. The clinical presentations of such hypersensitivity are various and range from mild reactions (e.g., maculopapular exanthema (MPE) and fixed drug eruption (FDE)), to drug-induced liver injury (DILI) and severe cutaneous adverse reactions (SCARs) (e.g., Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), drug reaction with eosinophilia and systemic symptoms (DRESS), and acute generalized exanthematous pustulosis (AGEP)). The common culprits of delayed drug hypersensitivity include anti-epileptics, antibiotics, anti-gout agents, anti-viral drugs, etc. Delayed drug hypersensitivity is proposed to be initiated by different models of molecular recognition, composed of drug/metabolite antigen and endogenous peptide, HLA presentation, and T cell receptor (TCR) interaction. Increasing the genetic variants of HLA loci and drug metabolic enzymes has been identified to be responsible for delayed drug hypersensitivity. Furthermore, preferential TCR clonotypes, and the activation of cytotoxic proteins/cytokines/chemokines, are also involved in the pathogenesis of delayed drug hypersensitivity. This review provides a summary of the current understanding of the molecular recognition, genetic susceptibility, and immune mediators of delayed drug hypersensitivity.

Resensitization in suspected penicillin allergy

BACKGROUND

The diagnosis of allergic reactions to penicillins (AR-PEN) is very complex as there is a loss of sensitization over time, which leads to negative skin tests (STs) and specific IgE in serum, and even to tolerance to the drug involved. However, STs may become positive after subsequent exposure to the culprit drug (resensitization), with the risk of inducing potentially severe reactions. The exact rate of resensitization to penicillins is unknown, ranging from 0% to 27.9% in published studies.

OBJECTIVES

To analyze the rate of resensitization in patients with suggestive AR-PEN by repeating STs (retest) after an initial evaluation (IE).

MATERIAL AND METHODS

Patients with suspected AR-PEN were prospectively evaluated between 2017 and 2020. They underwent STs, and a randomized group also underwent a drug provocation test (DPT) with the culprit. Only patients with negative STs and/or DPT were included. All included cases were retested by STs at 2-8 weeks.

RESULTS

A total of 545 patients were included: 296 reporting immediate reactions (IRs) and 249 non-immediate reactions (NIRs). Eighty (14.7%) cases had positive results in retest (RT+): 63 (21.3%) IRs and 17 (6.8%) NIRs (p < 0.0001). The rate of RT+ was higher in anaphylaxis compared with all other reactions (45.8% vs 9.1%, p < 0.0001). The risk of RT+ was higher from the fifth week after IE (OR: 4.64, CI: 2.1-11.6; p < 0.001) and increased with the patient's age (OR: 1.02; CI: 1.01-1.04; p = 0.009).

CONCLUSIONS

Due to the high rate of resensitization, retest should be included in the diagnostic algorithm of IRs to penicillins after an initial negative study, especially in anaphylaxis, to avoid potentially severe reactions after subsequent prescriptions of these drugs.

In Vitro Assays for Diagnosis of Drug-Induced Nonsevere Exanthemas: A Systematic Review and Meta-Analysis

Frequent mislabelled causal relationship between drug hypersensitivity reactions and culprit drugs reinforces the need for an accurate diagnosis. The systematic reviews and meta-analyses of in vitro assays published so far focused on immediate reactions and the most severe delayed reactions, while the most frequent drug-induced delayed reactions-nonsevere exanthemas-have been underestimated. We aim to fill this gap. A systematic review of studies on in vitro assays used in the diagnosis of nonsevere drug-induced delayed reactions was conducted following the methodology of Preferred Reporting Items for a Systematic Review and Meta-analysis of Diagnostic Test Accuracy Studies Statement. The EMBASE and PubMed databases were searched. We have included 33 studies from which we extracted the data, then performed meta-analysis where possible, or synthesised the evidence narratively. The quality of the analysed studies was assessed with the QUADAS-2 tool. The tests identified the most frequently were lymphocyte transformation test (LTT), ELISpot, and ELISA. In the meta-analysis carried out for LTT in reactions induce by beta-lactams, the pool estimate of sensitivity and specificity amounted to 49.1% (95% CI: 14.0%, 85.0%) and 94.6% (95% CI: 81.7%, 98.6%), respectively. The studies showed heterogeneity in study design and laboratory settings, which resulted in a wide range of specificity and sensitivity of testing.

Characterization of immunologically detectable T-cell sensitization, Immunohistochemical detection of pro-inflammatory cytokines, and clinical parameters of patients after allogeneic intraoral bone grafting procedures: a prospective randomized controlled clinical trial in humans

BACKGROUND

The null hypotheses were tested that intraoral bone augmentation using two different allogeneic materials has no impact on the patient's blood levels of material-specific lymphocytes and on the immunohistochemical detection of pro-inflammatory cytokines IL-1α, IL1ß and TNF-α and T-cell markers CD4, CD8 in biopsies of the test groups.

METHODS

In this prospective RCT, 60 systemically healthy participants were randomly assigned to two allogeneic test groups (1: Maxgraft®, freeze-dried, multiple donors, and 2: Puros®, solvent-dehydrated, single donor) and an autologous control group (10 patients). Plasma samples were collected pre-(T1) and postoperatively (2 weeks (T2) and 4 months (T3)). The Lymphocyte Transformation Test (LTT) was used for analyzing levels of transformed lymphocytes for type IV immune reactions by 3H-thymidine activity. Bone biopsies were harvested at T3 and immunohistochemically analyzed for IL-1α, IL1ß, TNF-α, CD4, CD8 and correlated with the immunological and clinical findings.

RESULTS

A statistically significant difference between the tested materials was observed for LTT measurements at T3 (p = 0.033). Furthermore, three groups were identified: Group A (LTT negative T1-T3, n = 48), group B (LTT positive T1-T3, n = 7), group C (developing positive LTT at T2, n = 5). A highly significant elevation of IL-1α, IL1ß, TNF-α in patients of group C (p = 0.0001) and a significant elevation of CD4+ cells in patients of group B (p = 0.005) was shown.

CONCLUSION

Our data show that following allogeneic bone grafting, local and systemic immunological reactions can be detected in some patients. These findings were statistically significant for the timepoint T3 between the tested materials as well as for the groups B and C correlated with group A for both tested materials. Therefore, the null hypotheses were rejected. A preoperative compatibility test for allogeneic materials in order to improve patient safety and the predictability of these materials would be desirable.

TRIAL REGISTRATION

Ethical commission of the Ärztekammer Hamburg, Germany (PV5211) as well as by the German Registry of Clinical Studies (DRKS00013010) on 30/07/2018 ( http://apps.who.int/trialsearch/ ).

Perioperative Anaphylaxie – alte Zöpfe und Neues zu den Auslösern

Perioperative Anaphylaxien werden mit mindestens 1:6000 angegeben. Neue Kenntnisse der Pathophysiologie der anaphylaktischen Reaktionen beziehen die Auslösung über das Mastzell-related G-Protein und die Komplementaktivierungs-abhängige Pseudoallergie mit ein. Neu beschriebene Auslöser sind das Chlorhexidin oder Gelatine-Produkte, eingesetzt zur Blutstillung oder blaue Farbstoffe zur intraoperativen Markierung. Wachsamkeit ist in Hinblick auf biphasische Reaktionen geboten. Propofol darf mittlerweile bei Ei- und Sojaallergikern eingesetzt werden.

Antibiotic hypersensitivity in cystic fibrosis - Low frequency of anaphylaxis over 16 000 courses

AIMS

Drug hypersensitivity reactions (DHR) to antibiotics are common and a substantial issue in managing patients with cystic fibrosis (CF). This study aimed to assess the prevalence and clinical features as well as risk factors of DHR to antibiotics in CF.

METHOD

A 20-year retrospective study was conducted among 226 CF patients (100 children and 126 adults) attending our centre. The Swedish Registry for Cystic Fibrosis and electronic medical records enabled us to ascertain the number and routes of antibiotic courses. All suspected DHR were evaluated.

RESULTS

The patients had a total of 16 910 antibiotic courses, of which 6832 (40%) were intravenously administered. Of 226 enrolled CF patients, 70 (31%) developed overall 131 DHR to antibiotics. The prevalence of DHR increased with advancing age (P < .001). Beta-lactams elicited 71% of all DHR and piperacillin was the most common single culprit (30% of intravenous and 24% of all DHR). Reactions were mild to moderate and mostly limited to skin; no severe cutaneous adverse reactions were observed. Additionally, anaphylaxis was rare, constituting 2.3% (3/131) of all DHR. Patients with DHR were exposed to significantly more courses of antibiotics than those without DHR (median 124 vs. 46, retrospectively, P < .001).

CONCLUSIONS

DHR to antibiotics, particularly to beta-lactams, are increased in CF patients, and associated with a higher number of cumulative exposures because of recurrent infections. However, severe cutaneous or systemic DHR, such as anaphylaxis, appear to be rare.

Confirmation of Drug Allergy in a General Pediatrics Outpatient Clinic

BACKGROUND

The studies including diagnostic workup on true drug allergy in children are limited.

OBJECTIVE

This study aimed to evaluate the frequency of confirmed drug allergies in children with a history of suspected drug allergies who had applied to the general paediatric outpatient clinics of our hospital due to various health problems.

METHODS

The history of drug allergy was questioned in children who applied to the general pediatric outpatient clinics of our hospital. Allergy tests were performed to confirm drug allergy in children whose history was compatible with drug allergy.

RESULTS

In this study, the parents of 5,553 children aged between 4 months and 17.9 years were asked, "Has your child ever developed an allergy after drug use?". Seven percent of parents (n=389/5,553) thought that their child had a drug allergy. When these patients were evaluated by a paediatric allergist, it was suspected that 21.1% (n=82/389) had a drug allergy. When diagnostic tests were performed for drug allergies, drug allergy was confirmed in only 4.2% (n=3/72). As a result, the frequency of drug allergies according to the history was 1.47% (n=82/5,553) in the population we studied, while the frequency of confirmed drug allergies was found to be 0.05% (n=3/5,553).

CONCLUSION

The patient and/or parent statements alone are not sufficient for the diagnosis of drug allergies in children. In order to confirm or rule out drug allergies, drug allergy tests must be performed and so unnecessary drug restrictions can be avoided.

Pharmacological Prevention of Hypersensitivity Reactions Caused by Iodinated Contrast Media: A Systematic Review and Meta-Analysis

Objectives: Hypersensitivity reactions (HSRs) are uncommon but serious adverse events following the administration of iodinated contrast media (ICM) prior to CT imaging. While premedication is almost universally given in high-risk patients, there is a lack of evidence regarding the efficacy of such premedication. This study aims to determine the efficacy of premedication with corticosteroids prior to ICM administration in the prevention of HSRs through meta-analysis. Materials and Methods: An extensive review of the literature yielded 404 potentially relevant studies. Of these, five studies met the inclusion criteria of this meta-analysis. Pooled HSR event rates were obtained from each of the studies for both patients who had and who had not received premedication with corticosteroids. Heterogeneity between studies was also determined. Results: A total of 736 patients across all five studies were included in the analysis. Patients who did not receive premedication had initial pooled HSR rates of 0.16 (95% CI, 0.07−0.35) across all studies. Following premedication, pooled HSR rates dropped to 0.02 (95% CI, 0.01−0.06). Patients who had prior HSRs were significantly less likely to experience HSRs (OR = 0.09; 95% CI, 0.03−0.25; p < 0.00001) after treatment with premedication. Conclusions: This meta-analysis offers evidence for the reduction in the recurrence of moderate and severe HSRs in patients who have a history of such reactions. Premedication with corticosteroids prior to ICM administration is thus highly recommended in high-risk patients.

Cutaneous Adverse Drug Reactions (CADRs)—Statistical Analysis of the Causal Relationship between the Drug, Comorbidities, Cofactors, and the Cutaneous Reaction—A Single-Centered Study

Cutaneous adverse drug reactions (CADRs) are among the most common types of drug hypersensitivity reactions. The purpose of this study was to evaluate the clinical spectrum of CADRs and to determine the causal relationship between drugs, comorbidities, cofactors or concomitant symptoms, and cutaneous reactions. A retrospective hospital-based study was carried out over a period of 10 years at the Department of Dermatology, Sexually Transmitted Diseases and Clinical Immunology at the University of Warmia and Mazury in Olsztyn to record various CADRs, comorbidities, cofactors, and the suspected drug in hospitalized patients. The data were subjected to statistical analysis. CADRs were diagnosed in a total of 140 patients, 32.14% of whom were men and 67.86% of whom were women. The mean age was 66.33 years. The most commonly suspected drugs were Allopurinol 12.86%, Amoxicillin with clavulanic acid 10%, Amoxicillin 9.29%, Paracetamol 6.43%, Metronidazole 5%, and Carbamazepine 5%. Attention should be paid to the possibility of using a substitute for a suspected drug if CADRs arise, or discontinuing a drug that is unjustifiably overused. The results of the present study should also prompt research into a potential treatment that could be implemented concurrently with a drug that has a high predisposition to cause CADRs.

Potential Biomarker Identification by RNA-seq analysis in Antibiotic-related Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS): a Pilot Study

One of the most severe forms of cutaneous adverse drug reactions is 'drug reaction with eosinophilia and systemic symptoms' (DRESS), hence subsequent avoidance of the causal drug is imperative. However, attribution of drug culpability in DRESS is challenging and standard skin allergy tests are not recommended due to patient safety reasons. Whilst incidence of DRESS is relatively low, between 1:1000 to 1:10,000 drug exposures, antibiotics are a commoner cause of DRESS and absence of confirmatory diagnostic test can result in unnecessary avoidance of efficacious treatment. We therefore sought to identify potential biomarkers for development of a diagnostic test in antibiotic-associated DRESS. Peripheral blood mononuclear cells (PBMCs) from a 'discovery' cohort (n = 5) challenged to causative antibiotic or control were analysed for transcriptomic profile. A panel of genes was then tested in a validation cohort (n = 6) and compared to tolerant controls and other inflammatory conditions which can clinically mimic DRESS. A scoring system to identify presence of drug hypersensitivity was developed based on gene expression alterations of this panel. The DRESS transcriptomic panel identified antibiotic-DRESS cases in a validation cohort but was not altered in other inflammatory conditions. Machine learning or differential expression selection of a biomarker panel consisting of six genes (STAC, GPR183, CD40, CISH, CD4, and CCL8) showed high sensitivity and specificity (100% and 85.7-100% respectively) for identification of the culprit drug in these cohorts of antibiotic-associated DRESS. Further work is required to determine whether the same panel can be repeated for larger cohorts, different medications, and other T cell mediated drug hypersensitivity reactions.

Hypersensitivity Reactions to Iodinated Contrast Media

At present, iodinated contrast media (ICM) are mostly non-ionic, have low osmolality, and are safe. Even if adverse drug reactions (ADRs) occur, most are chemo-toxic symptoms and require only observation or H1 antihistamines. However, rare, unpredictable, and even life-threatening hypersensitivity can still occur. The aim of this review is to summarize the issues that all relevant staff need to know about and be able to respond to. The most significant risk factor for ICM hypersensitivity is a history of ICM hypersensitivity. For high-risk populations, we must cautiously weigh the advantages and disadvantages of premedication and be aware that breakthrough reactions may still occur. The best policy for patients with a history of severe ICM hypersensitivity is to avoid the same ICM. If ICM are inevitable, skin tests, in vitro tests, and drug provocation tests may help to find a feasible alternative that is safer. The severity of the hypersensitivity is correlated with the positivity rate of these tests, so there is no need for further investigations for patients with only mild reactions. We should also keep in mind that even excipients in ICM may induce hypersensitivity. Detailed, standardized documentation is essential for correct diagnosis and the prevention of future occurrence.

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.

Advances and highlights in T and B cell responses to drug antigens

The immunological mechanisms involved in drug hypersensitivity reactions (DHRs) are complex, and despite important advances, multiple aspects remain poorly understood. These not fully known aspects are mainly related to the factors that drive towards either a tolerant or a hypersensitivity response and specifically regarding the role of B and T cells. In this review, we focus on recent findings on this knowledge area within the last 2 years. We highlight new evidences of covalent and non-covalent interactions of drug antigen with proteins, as well as the very first characterization of naturally processed flucloxacillin-haptenated human leukocyte antigen (HLA) ligands. Moreover, we have analysed new insights into the identification of risk factors associated with the development of DHRs, such as the role of oxidative metabolism of drugs in the activation of the immune system and the discovery of new associations between DHRs and HLA variants. Finally, evidence of IgG-mediated anaphylaxis in humans and the involvement of specific subpopulations of effector cells associated with different clinical entities are also topics explored in this review. All these recent findings are relevant for the underlying pathology mechanisms and advance the field towards a more precise diagnosis, management and treatment approach for DHRs.

Outcome of a de-labelling algorithm compared with results of penicillin (β-lactam) allergy testing

Background

Penicillin allergy labels frequently impede guideline-directed treatment with a penicillin or other β-lactam antibiotics. Despite presumed allergy, targeted questioning may indicate a low probability of sensitization and permit reasonably safe administration of the antibiotic in question. In this study, we evaluated a standardized algorithm aiming to differentiate non-allergic patients from those with true allergic β-lactam hypersensitivity.

Methods

We retrospectively applied a de-labelling algorithm in 800 consecutive patients with suspected β-lactam hypersensitivity. All had undergone complete allergy work-up permitting to definitely exclude or diagnose β-lactam allergy between 2009 and 2019.

Results

In 595 (74.4%) out of 800 cases evaluated, β-lactam allergy could be excluded by negative challenge testing. IgE-mediated anaphylaxis was diagnosed in 70 (8.7%) patients, delayed-type hypersensitivity in 135 (16.9%). In 62 (88.6%) anaphylaxis cases, the algorithm correctly advised to use an alternative antibiotic. Accuracy was higher in patients with moderate to severe anaphylaxis (97.7%) compared to those with a history of mild reactions (73.1%). The algorithm correctly identified 122 (90.4%) patients with proven delayed-type hypersensitivity. It permitted de-labelling in 330 (55.5%) out of 595 patients with diagnostic exclusion of penicillin hypersensitivity, but failed to identify the remaining 265 (44.5%) as low-risk cases.

Conclusions

The algorithm detected 89.8% of cases with penicillin (β-lactam) allergy, sensitivity was optimal for moderate to severe anaphylaxis. Study data justify the implementation of a standardized de-labelling algorithm under close supervision in order to permit guideline-directed treatment and reduce the use of broad-spectrum antibiotics as part of an antibiotic stewardship program.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13223-022-00659-1.

Patch testing in Drug reaction with eosinophilia and systemic symptoms (DRESS): a literature review

The literature on positive patch test results in drug reaction with eosinophilia and systemic symptoms (DRESS) is reviewed. 105 drugs were identified that have together caused 536 positive patch tests in 437 patients suffering from DRESS. By far most reactions (n=145) were caused by carbamazepine, followed by amoxicillin, isoniazid, phenytoin, ethambutol, fluindione, phenobarbital, rifampicin, and ceftriaxone; 43 drugs each caused a single case only. The drug classes causing the highest number of reactions are anticonvulsants (39%), beta-lactam antibiotics (20%), antituberculosis agents (11%), non-beta-lactam antibiotics (6%) and iodinated contrast media (5%). The sensitivity of patch testing (percentage of positive reactions) is high for anticonvulsants (notably carbamazepine), beta-lactam antibiotics (notably amoxicillin) and possibly iodinated contrast media. Allopurinol and sulfasalazine frequently cause DRESS, but never give positive patch tests. Patch testing in DRESS appears to be safe, although mild recurrence of DRESS symptoms, mostly skin reactions, may not be rare. Multiple drug hypersensitivity was found to occur in 16% of all patients, but it is argued that the true frequency is (far) higher. Clinical aspects of DRESS, including diagnosing the disease and identifying culprit drugs (patch tests, intradermal tests, in vitro tests, challenge tests) are also provided, emphasizing the role of patch testing. This article is protected by copyright. All rights reserved.