Prevalence of hypersensitivity reactions in various forms of mastocytosis: A pilot study of 2485 adult patients with mastocytosis collected in the ECNM registry

BACKGROUND

Hypersensitivity reactions (HR) are common in mastocytosis. However, little is known about triggers and risk factors. The registry of the European Competence Network on Mastocytosis (ECNM) enables reliable studies in a larger cohort of mastocytosis patients. We assessed prevalence, triggers and risk factors of HR in adults with mastocytosis in the ECNM registry.

METHODS

Data were collected in 27 ECNM centers. We analyzed potential triggers (Hymenoptera venoms, food, drug, inhalant and others) and risk factors at diagnosis and during follow-up. The study group consisted of 2485 adults with mastocytosis, 1379 women (55.5%) and 1106 men (44.5%). Median age was 48.2 years (range 18-91 years).

RESULTS

Nine hundred and forty eight patients (38.1%) reported one or more HR`. Most common triggers were Hymenoptera venoms in cutaneous mastocytosis (CM) and indolent systemic mastocytosis (ISM), whereas in advanced SM (advSM), most common elicitors were drugs, including nonsteroidal anti-inflammatory agents and penicillin. In multivariate analyses, tryptase level < 90 ng/mL, <15% infiltration by mast cells in bone marrow biopsy-sections, and diagnosis of ISM were identified as independent risk factors for HR. For drug-induced HR, prominent risk factors were advSM and high tryptase levels. New reactions were observed in 4.8% of all patients during 4 years follow-up.

CONCLUSIONS

HR are mainly triggered by Hymenoptera venoms in patients with CM and ISM and by drugs in patients with advSM. Tryptase levels <90 ng/mL, mast cell bone marrow infiltration <15%, and WHO category ISM are predictors of HR. New HR occur in 4.8% of all patients within 4 years.

Basophil activation test in the diagnostic workup of perioperative anaphylaxis due to neuromuscular blocking agents: A case series and implications for practice

In Australia, neuromuscular blocking agents are the leading cause of perioperative anaphylaxis. Current investigation of suspected anaphylaxis includes tryptase levels, serum immunoglobulin E (IgE) levels, and skin testing, including intradermal testing and skin prick testing. The gold standard for the diagnosis of a hypersensitivity reaction is a challenge test, but this poses a risk to patient safety. An alternative test, known as the basophil activation test (BAT) is a form of cellular in vitro testing using flow cytometry to measure the degree of basophil degranulation within a sample of blood following exposure to an allergen. This acts as a surrogate marker for mast cell and basophil activation, thereby identifying IgE-mediated allergy. It is most commonly used to supplement equivocal findings from initial in vitro testing to assist in confirming the diagnosis of a hypersensitivity reaction and identify the causative agent. We present a case series in which five patients with suspected anaphylaxis underwent a BAT, demonstrating its role and limitations in allergy testing within Australia.

Asparaginase-specific basophil recognition and activation predict Asparaginase hypersensitivity in mice

Background

Asparaginase (ASNase) is a crucial part of acute leukemia treatment, but immune responses to the agent can reduce its effectiveness and increase the risk of relapse. Currently, no reliable and validated biomarker predicts ASNase-induced hypersensitivity reactions during therapy. We aimed to identify predictive biomarkers and determine immune cells responsible for anaphylaxis using a murine model of ASNase hypersensitivity.

Methods

Our preclinical study uses a murine model to investigate predictive biomarkers of ASNase anaphylaxis, including anti-ASNase antibody responses, immune complex (IC) levels, ASNase-specific binding to leukocytes or basophils, and basophil activation.

Results

Our results indicate that mice immunized to ASNase exhibited dynamic IgM, IgG, and IgE antibody responses. The severity of ASNase-induced anaphylaxis was found to be correlated with levels of IgG and IgE, but not IgM. Basophils from immunized mice were able to recognize and activate in response to ASNase ex vivo, and the extent of recognition and activation also correlated with the severity of anaphylaxis observed. Using a multivariable model that included all biomarkers significantly associated with anaphylaxis, independent predictors of ASNase-induced hypersensitivity reactions were found to be ASNase IC levels and ASNase-specific binding to leukocytes or basophils. Consistent with our multivariable analysis, we found that basophil depletion significantly protected mice from ASNase-induced hypersensitivity reactions, supporting that basophils are essential and can be used as a predictive marker of ASNase-induced anaphylaxis.

Conclusions

Our study demonstrates the need for using tools that can detect both IC- and IgE-mediated hypersensitivity reactions to mitigate the risk of ASNase-induced hypersensitivity reactions during treatment.

Cross-reactivity among and between macrolides, lincosamides, and streptogramins: Study on the French pharmacovigilance database

BACKGROUND

Hypersensitivity reactions (HSR) are reported for the macrolides, lincosamides, and streptogramins (MLS) antibiotic family. Data about cross-reactivity among and between MLS remain scarce or controversial.

OBJECTIVES

The aim of this study was to provide an overview of hypersensitivity cross-reactions among MLSs based on data extracted from the French National Pharmacovigilance Database (FPVD).

METHODS

Cases of HSR to MLSs reported between January 1985 and December 2019 were extracted from the FPVD using standardized MedDRA queries (SMQ). Cases including an allergological test involving multiple MLSs and giving at least one positive result were included.

RESULTS

Of the 8394 cases reviewed, 149 were included. HSR mainly involved pristinamycin (n = 83; 53.2%) and spiramycin (n = 31; 19.9%). HSR to MLS was immediate in 54 cases and delayed in 94 cases. Skin tests represented the majority of the allergological tests performed (n = 728; 84.7%), followed by reintroduction tests (n = 79; 9.2%). Eighty-six cross-reactivities among MLS were identified in 62 cases (41.6%). All the 25 explorations performed for streptogramins showed cross-reactivities, but only 30/253 among macrolides (11.9%). Cross-reactivities between the three MLS were observed in 31/322 (9.6%) of the allergological explorations.

CONCLUSION

This study highlights the possibility of cross-reactivity among and between MLSs. Dermatologists and allergologists managing patients with HSR to MLSs should be aware of a risk of cross-reactivity among the macrolides and between the different classes of MLS and to perform MLSs allergological testing before recommending an alternative antibiotic, especially in severe drug hypersensitivity from the MLS family.

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.

First Case Report of Deferiprone-Induced Anaphylactic Reaction

A 56-year-old Thai male, known for allergies to penicillin, sulfa, and lincosamide, presented with hyperferritinemia. Upon initiating deferiprone therapy, the patient experienced recurrent episodes of dyspnea, culminating in anaphylactic shock. Treatment included subcutaneous epinephrine, intravenous chlorpheniramine, and hydrocortisone, which led to symptom resolution. This case constitutes the first case report of deferiprone-associated anaphylactic reactions.

Hypersensitivity reactions to proton pump inhibitors. An EAACI position paper

Proton pump inhibitors (PPIs) are invaluable therapeutic options in a variety of dyspeptic diseases. In addition to their well-known risk profile, PPI consumption is related to food and environmental allergies, dysbiosis, osteoporosis, as well as immediate and delayed hypersensitivity reactions (HSRs). The latter, although a rare event, around 1%-3%, due to the extraordinarily high rate of prescription and consumption of PPIs are related to a substantial risk. In this Position Paper, we provide clinicians with practical evidence-based recommendations for the diagnosis and management of HSRs to PPIs. Furthermore, the unmet needs proposed in the document aim to stimulate more in-depth investigations in the topic.

Hypersensitivity Reactions to Taxanes: A Multicenter Study for Outcomes and Safety of Rapid Drug Desensitization

PURPOSE

Taxanes can cause hypersensitivity reactions (HSRs), which pose a significant challenge in the treatment of malignancies. Patients who are eligible for rapid drug desensitization (RDD) can continue treatment; however, some patients experience breakthrough reactions (BTRs). Data about risk factors for BTRs during RDDs in patients with HSRs to taxanes are limited.

METHODS

This was a multicenter, retrospective study of patients with immediate-HSRs to taxanes. Initial HSRs were classified as grade 1, 2, or 3 based on severity. Prick/intradermal skin tests were performed with implicated taxanes. A 12-step protocol was used during RDD.

RESULTS

The study comprised 75 patients (F/M: 63/12, mean age 49.92 ± 11.72 years, 43 HSRs to paclitaxel, 32 HSRs to docetaxel). The majority of reactions (86.7%) occurred during the first or second exposure. The prevalence of drug allergy history was higher in patients with paclitaxel HSR than in those with docetaxel HSR, although it was not statistically significant (23.3% vs. 6.3%). The initial HSRs were mostly grade 2 (n = 50, 66.7%) or grade 3 (n = 22, 29.3%). Skin tests with implicated taxanes were done on 48 patients, and the rate of positive response in patients with grade 1, 2, and 3 initial HSRs were 50%, 17.6%, and 16.7%, respectively. . A total of 255 RDDs were completely performed, although BTRs occurred in 27 (grade 1, 55.6%; grade 2, 40.7%; grade 3, 3.7%). There were no statistically significant correlations between the risk of BTR and age, drug cycle, gender, positivity of skin test or atopy. The step reduction was successfully done on 9 eligible patients with mild or moderate HSRs during the 12-step RDDs.

CONCLUSIONS

Our experience demonstrates a 100% success rate in completing the 255 RDDs for taxanes, affirming the safety and efficacy of the RDD within the study population.

Recent findings on drug hypersensitivity in children

Drug hypersensitivity reactions (DHR) in children have a significant impact on clinical practice and public health. Both under-diagnosis (due to under-reporting) and over-diagnosis (due to the overuse of the term "allergy") are potential issues. The aim of this narrative review is to describe the most recent findings of DHR in children/adolescents and gaps regarding epidemiology, antibiotic allergy, antiepileptic hypersensitivity, vaccine allergy, and severe cutaneous adverse reactions (SCAR) in this age group.

Pharmacogenetics to prevent hypersensitivity reactions to antiepileptic drugs: is testing performed when indicated?

Extensive scientific evidence consistently demonstrates the clinical validity and utility of HLA-B*15:02 pre-screening in averting severe cutaneous adverse reactions (SCARs), namely Stevens-Johnson syndrome and toxic epidermal necrolysis, associated with carbamazepine or oxcarbazepine usage. Current practice guidelines and drug labeling actively advocate for pharmacogenetic pre-screening before initiating these antiepileptic drugs (AED), with particular emphasis on patients of Asian descent. However, there is a potential need to strengthen compliance with these recommendations. This retrospective study aimed to describe the pharmacogenetic pre-screening, documentation, and SCARs incidence for patients of Asian ancestry initiated on carbamazepine or oxcarbazepine at a large Northeastern USA healthcare system. Between 1 July 2016 and August 1, 2021, 27 patients with documented Asian heritage in the electronic health record (EHR) were included. The overall rate of HLA-B*15:02 pre-screening before carbamazepine or oxcarbazepine initiation was 4%. None who underwent pharmacogenetic pre-screening carried the associated HLA-B risk allele, and no SCARs were reported. Notably, pharmacogenetic results were not discretely entered into the EHR, and the results were only found as attached documents in the miscellaneous section of the EHR. There remains a significant opportunity for improving HLA-B*15:02 pre-screening for patients starting carbamazepine and oxcarbazepine to prevent SCARs in the USA.

Glycolysis: An early marker for vancomycin-specific T-cell activation

BACKGROUND

Vancomycin, a glycopeptide antibiotic used for Gram-positive bacterial infections, has been linked with drug reaction with eosinophilia and systemic symptoms (DRESS) in HLA-A*32:01-expressing individuals. This is associated with activation of T lymphocytes, for which glycolysis has been isolated as a fuel pathway following antigenic stimulation. However, the metabolic processes that underpin drug-reactive T-cell activation are currently undefined and may shed light on the energetic conditions needed for the elicitation of drug hypersensitivity or tolerogenic pathways. Here, we sought to characterise the immunological and metabolic pathways involved in drug-specific T-cell activation within the context of DRESS pathogenesis using vancomycin as model compound and drug-reactive T-cell clones (TCCs) generated from healthy donors and vancomycin-hypersensitive patients.

METHODS

CD4+ and CD8+ vancomycin-responsive TCCs were generated by serial dilution. The Seahorse XFe96 Analyzer was used to measure the extracellular acidification rate (ECAR) as an indicator of glycolytic function. Additionally, T-cell proliferation and cytokine release (IFN-γ) assay were utilised to correlate the bioenergetic characteristics of T-cell activation with in vitro assays.

RESULTS

Model T-cell stimulants induced non-specific T-cell activation, characterised by immediate augmentation of ECAR and rate of ATP production (JATPglyc). There was a dose-dependent and drug-specific glycolytic shift when vancomycin-reactive TCCs were exposed to the drug. Vancomycin-reactive TCCs did not exhibit T-cell cross-reactivity with structurally similar compounds within proliferative and cytokine readouts. However, cross-reactivity was observed when analysing energetic responses; TCCs with prior specificity for vancomycin were also found to exhibit glycolytic switching after exposure to teicoplanin. Glycolytic activation of TCC was HLA restricted, as exposure to HLA blockade attenuated the glycolytic induction.

CONCLUSION

These studies describe the glycolytic shift of CD4+ and CD8+ T cells following vancomycin exposure. Since similar glycolytic switching is observed with teicoplanin, which did not activate T cells, it is possible the master switch for T-cell activation is located upstream of metabolic signalling.

Assessing delayed penicillin hypersensitivity using the PENFAST+ score

Introduction

Approximately 10% of individuals report a suspected allergy to penicillin, but according to allergy work-ups, only 10%-15% of them are truly allergic. A clinical decision score, the PEN-FAST, was developed and validated to identify adults with low-risk penicillin allergy.

Objectives

The objective of this study was to improve the performance of the PEN-FAST score, particularly for those with delayed hypersensitivity (HS), by improving the negative predictive value.

Methods

STEP 1: Retrospective evaluation of the PEN-FAST score in patients with proven immediate and delayed penicillin allergy. STEP 2: Identification of additional criteria among Step 1 patients misclassified by PEN-FAST score. Development of the PEN-FAST+ score using multivariable logistic regression in a prospective cohort of patients with a suspicion of HS to penicillin. STEP 3: Comparison of diagnostic performances of PEN-FAST and PEN-FAST+ scores.

Results

The PEN-FAST score showed limitations in predicting the relapse of immediate skin HS or delayed maculopapular exanthema, with 28.6% and 38.4% of patients misclassified, respectively. We identified two potential additional criteria: skin rash lasting more than 7 days and immediate reaction occurring in less than 1 h (generalized or localized on palmoplantar area or scalp itching/heat feeling). A total of 32/252 (12.7%) patients were confirmed to be allergic to penicillin. With PEN-FAST, 37% of patients (n = 10) with delayed allergic penicillin HS were misclassified. With PEN-FAST+, 3 patients with delayed HS confirmed by a ST (11.1%) were misclassified. The AUC was significantly higher for PEN-FAST+ than PEN-FAST (85% vs. 72%, p = 0.03).

Implementation of a multidisciplinary inpatient drug desensitization program

PURPOSE

The purpose of this project was to analyze the process of adult inpatient drug desensitization and to create a multidisciplinary standardized procedure with the aim of improving patient safety, efficiency, length of stay, and patient satisfaction.

SUMMARY

A team consisting of physicians, pharmacists, nurses, critical care specialists, and operational capacity managers was created. The electronic health system was queried to evaluate the frequency of desensitizations, level of care, implicated medications, and length of stay. An electronic desensitization request form was created along with a desensitization team and email listserver for notification of key stakeholders.

CONCLUSION

A standardized, safe, and efficient process for inpatient drug desensitization requires advance planning and participation from all disciplines involved. Operational and logistical aspects of desensitization are crucial components of rapid drug desensitization. A structured, multidisciplinary approach to inpatient desensitization is feasible.

Sulfasalazine-Induced Delayed Hypersensitivity Reaction Presenting as Fever, Aseptic Meningitis, and Mesenteric Panniculitis in a Patient with Seronegative Arthritis

BACKGROUND An 82-year-old woman presented with acute pyrexial illness and mesenteric panniculitis and developed biochemical aseptic meningitis (cerebrospinal fluid pleocytosis with no identifiable pathogen). Investigation determined her illness was likely a delayed hypersensitivity reaction caused by sulfasalazine. Sulfasalazine-induced aseptic meningitis is a rare condition often diagnosed late in a patient's admission owing to initial non-specific illness symptomatology requiring the exclusion of more common "red flag" etiologies, such as infection and malignancy. CASE REPORT An 82-year-old woman with a history of recurrent urinary tract infections and seronegative arthritis presented with a 3-day history of fatigue, headache, dyspnea, and lassitude. On admission, she was treated as presumed sepsis of uncertain source owing to pyrexia and tachycardia. Brain computer tomography (CT) revealed no acute intracranial abnormality. Furthermore, CT of the chest, abdomen, and pelvis did not reveal any source of sepsis or features of malignancy. After excluding infective etiologies with serological and cerebrospinal fluid testing, sulfasalazine-induced aseptic meningitis (SIAM) was diagnosed. The patient was then commenced on intravenous steroids, resulting in immediate defervescence and symptom resolution. CONCLUSIONS SIAM remains a diagnostic challenge since patients present with non-specific signs and symptoms, such as pyrexia, headaches, and lassitude. These patients require a thorough investigative battery starting with anamnesis, physical examination, biochemical testing, and radiologic imaging. This case illustrates the need for a high suspicion index of drug-induced hypersensitivity reaction in a rheumatological patient with pyrexial illness where infective etiologies have been confidently excluded. Prompt initiation of intravenous steroids in SIAM provides a dramatic recovery and resolution of symptoms.

Nsaids Linked to IgA-Mediated Hypersensitivity Vasculitis and Purpura Fulminans-Like Eruption

Background

IgA vasculitis and hypersensitivity reactions following exposure to non-steroidal anti-inflammatory drugs (NSAIDs) are very rarely associated with purpura fulminans (PF). The latter is a coagulation event characterised by decreased levels of protein C and a rapidly progressive purpuric rash, often leading to ischaemia, amputations and death.

Case summary

A previously healthy 66-year-old man presented with a vasculitic rash and abdominal pain following exposure to naproxen (NSAID), which quickly deteriorated to purpura fulminans-like eruption and skin necrosis, mainly involving the face and hands. The presence of IgA sediments on skin biopsy and decreased levels of complement as well as protein C pointed to an immune-mediated inflammatory process. Dramatic clinical escalation with immediate risk to organs and life required an aggressive and broad-spectrum therapeutic approach in an intensive care setting. Clinical improvement and complete reconstitution of protein C were achieved following plasma exchange with fresh frozen plasma (FFP) and immunosuppression with glucocorticoids with no persistent organ damage.

Conclusions

This rare case illustrates the catastrophic cross links between NSAIDs, IgA-mediated hypersensitivity vasculitis and purpura fulminans-like syndrome. A high index of suspicion is required for the evaluation of environmental exposures such as drugs and infections in patients with vasculitis and/or purpura. A rapid and comprehensive therapeutic approach should be implemented to avoid multi-organ damage, amputations and death. Complete avoidance of the offending agent is key for future prevention of recurrence.

LEARNING POINTS

This case illustrates a rare cross link between a commonly used drug (NSAIDs) and severe, life-threatening hypersensitivity reactions (IgA vasculitis and purpura fulminans-like eruption).These events require a high index of suspicion and emphasise the importance of considering environmental exposures such as drugs in the immediate diagnosis of both conditions.In addition to long-term drug avoidance, early and aggressive interventions are required to avoid organ damage, amputations or death.

Drug hypersensitivity and eosinophilia: The decisive role of p-i stimulation

Eosinophilia is a common finding in drug hypersensitivity reactions (DHR). Its cause is unclear, as neither antigen/allergen-driven inflammation nor clonal expansion is involved. Most delayed-DHRs are due to p-i (pharmacologic interaction of drugs with immune receptors). These are off-target activities of drugs with immune receptors that result in various types of T-cell stimulation, some of which involve excessive IL-5 production. Functional and phenotypic studies of T-cell clones and their TCR-transfected hybridoma cell lines revealed that some p-i-induced drug stimulations occur without CD4/ CD8 co-receptor engagement. The CD4/CD8 co-receptors link Lck (lymphocyte-specific protein tyrosine kinase) and LAT (linker for activation of T cells) to the TCR. Alteration of Lck or LAT can result in a TCR signalosome with enhanced IL-5 production. Thus, if a more affine TCR-[drug/peptide/HLA] interaction allows bypassing the CD4 co-receptor, a modified Lck/LAT activation may lead to a TCR signalosome with elevated IL-5 production. This "IL-5-TCR-signalosome" hypothesis could also explain eosinophilia in superantigen or allo-stimulation (graft-versus-host disease), in which evasion of CD4/CD8 co-receptors has also been described. It may open new therapeutic possibilities in certain eosinophilic diseases by directly targeting the IL-5-TCR signalosome.

Why drug exposure is frequently associated with T-cell mediated cutaneous hypersensitivity reactions

Cutaneous hypersensitivity reactions represent the most common manifestation of drug allergy seen in the clinic, with 25% of all adverse drug reactions appearing in the skin. The severity of cutaneous eruptions can vastly differ depending on the cellular mechanisms involved from a minor, self-resolving maculopapular rash to major, life-threatening pathologies such as the T-cell mediated bullous eruptions, i.e., Stevens Johnson syndrome/toxic epidermal necrolysis. It remains a significant question as to why these reactions are so frequently associated with the skin and what factors polarise these reactions towards more serious disease states. The barrier function which the skin performs means it is constantly subject to a barrage of danger signals, creating an environment that favors elicitation. Therefore, a critical question is what drives the expansion of cutaneous lymphocyte antigen positive, skin homing, T-cell sub-populations in draining lymph nodes. One answer could be the heterologous immunity hypothesis whereby tissue resident memory T-cells that express T-cell receptors (TCRs) for pathogen derived antigens cross-react with drug antigen. A significant amount of research has been conducted on skin immunity in the context of contact allergy and the role of tissue specific antigen presenting cells in presenting drug antigen to T-cells, but it is unclear how this relates to epitopes derived from circulation. Studies have shown that the skin is a metabolically active organ, capable of generating reactive drug metabolites. However, we know that drug antigens are displayed systemically so what factors permit tolerance in one part of the body, but reactivity in the skin. Most adverse drug reactions are mild, and skin eruptions tend to be visible to the patient, whereas minor organ injury such as transient transaminase elevation is often not apparent. Systemic hypersensitivity reactions tend to have early cutaneous manifestations, the progression of which is halted by early diagnosis and treatment. It is apparent that the preference for cutaneous involvement of drug hypersensitivity reactions is multi-faceted, therefore this review aims to abridge the findings from literature on the current state of the field and provide insight into the cellular and metabolic mechanisms which may contribute to severe cutaneous adverse reactions.

Taxanes hypersensitivity is not a risk factor for severe reactions to SARS-CoV-2 vaccines

Summary

Background. Hypersensitivity reactions (HSR) to taxanes have been related to a complement activation by their excipients, polyoxyethylated castor oil and Polysorbate 80, structurally related to those of SARS-CoV-2 vaccines. The aim of this study was to verify the presence of a higher risk of HSR to SARS-CoV-2 vaccines in patients with history of HSR to taxanes. Methods. Patients with history of HSR to taxanes were evaluated before the vaccination in our center and underwent skin tests for PEG and Polysorbate 80 (PandP). Some patients completed the vaccination course in other centers without prior PandP skin tests because they had not manifested taxanes hypersensitivity before vaccination, or because those tests were not available. Results. 50 patients were evaluated. 100% of patients with history of hypersensitivity to taxanes completed the vaccine course with no cases of anaphylaxis. 33 underwent skin tests for PandP before the vaccination and no correlation was found between the positivity of PandP and taxanes skin tests (p = 0.538). 7 patients developed mild symptoms during skin tests and vaccination, similar but weaker than those suffered at the time of the taxane infusion, independently from the results of skin tests. Conclusions. In our cohort patients with history of reaction to taxanes were not at higher risk to develop anaphylaxis to SARS-CoV-2 vaccines. However, a common non-IgE mediated mechanism behind those HSRs cannot be completely excluded. This can only account for mild and harmless symptoms in case of SARS-CoV-2 vaccines. However, prudence is still recommended in these patients.

Alpha-gal syndrome-Food or drug allergy: A case report

Alpha-gal syndrome is an immunoglobulin E-mediated hypersensitivity characterized by delayed allergic reactions to ingested products containing alpha-gal carbohydrate. We present a patient with recurrent urticaria and suspected repaglinide hypersensitivity, who was eventually diagnosed with alpha-gal syndrome, wanting to emphasize possible drug allergy misdiagnosis and required caution with the medication choice.

Guideline for allergological diagnosis of drug hypersensitivity reactions: S2k Guideline of the German Society for Allergology and Clinical Immunology (DGAKI) in cooperation with the German Dermatological Society (DDG), the Association of German Allergologists (ÄDA), the German Society for Pediatric Allergology (GPA), the German Contact Dermatitis Research Group (DKG), the German Society for Pneumology (DGP), the German Society of Otorhinolaryngology, Head and Neck Surgery, the Austrian Society of Allergology and Immunology (ÖGAI), the Austrian Society of Dermatology and Venereology (ÖGDV), the German Academy of Allergology and Environmental Medicine (DAAU), and the German Documentation Center for Severe Skin Reactions (dZh)

Not available.

Tools for Etiologic Diagnosis of Drug-Induced Allergic Conditions

Drug hypersensitivity reactions are a serious concern in clinical practice because they can be severe and result in lifelong sequelae. An accurate diagnosis and identification of the culprit drug is essential to prevent future reactions as well as for the identification of safe treatment alternatives. Nonetheless, the diagnosis can be challenging. In vivo and in vitro tests can be helpful, although none are conclusive; therefore, the tests are not usually performed in isolation but as part of a diagnostic algorithm. In addition, some in vitro tests are only available in research laboratories, and standardization has not been fully accomplished. Collaborating research is needed to improve drug hypersensitivity reaction diagnosis. In this review, we update the current available in vivo and in vitro tools with their pros and cons and propose an algorithm to integrate them into clinical practice.

Fidaxomicin-Associated Hypersensitivity Reactions: Report of a Morbilliform Drug Eruption

PurposeWe report a probable case of morbilliform drug eruption secondary to fidaxomicin in a patient with Clostridioides difficile infection (CDI). Summary: A 62-year-old female presented to our institution's emergency department (ED) with symptoms consistent with Clostridioides difficile infection. The patient was prescribed 2 weeks of oral vancomycin for CDI prior to presentation. Given insufficient response to vancomycin, the patient was started on fidaxomicin with a planned 10-day course. After 2 doses of fidaxomicin, the patient developed a rash on her back that spread within 24 hours. The patient did not experience relief upon administration of a variety of medications for allergic reaction. Improvement was noted upon discontinuation of fidaxomicin. The Food and Drug Administration reports that < 2% of adults treated with fidaxomicin experience a rash as an adverse effect. Conclusion: Fidaxomicin was a probable cause of morbilliform drug eruption in our patient with CDI. The patient improved upon discontinuation of fidaxomicin.

Drug provocation tests in children: All that glitters is not gold

A proper allergy work-up, based on the gold standard drug provocation test (DPT), usually rules out suspected drug hypersensitivity in children. These tests are generally open, given their high efficiency compared with double-blind placebo-controlled DPTs. Although their negative predictive value is excellent, no studies have calculated their positive predictive value, highly dependent on the prevalence of the disease. Most studies have found a rate of <5%-10% of true beta-lactam hypersensitivity in children. Given this low prevalence (pre-test probability), a few false-positive results can significantly reduce the estimated positive predictive value. False positives may arise from the nocebo effect during the test, including nocebo by proxy, or from observer bias, which depends on professional expertise and organizational circumstances. Some studies have found a high rate of tolerance on a second DPT in children who failed the first, but these results may be affected by the interval between the two tests, of a year or more in most cases, reflecting a loss of hypersensitivity over time. Taking into account the low rate of positive DPTs, with commonly mild reactions, we suggest confirming nonsevere positive DPTs with a second provocation performed soon after the first, especially in the case of beta-lactam antibiotics, in order to improve the diagnostic accuracy, de-label more patients, and achieve a better estimation of true drug hypersensitivity prevalence. In case of mild immediate reactions, the potential benefits of a second DPT should be carefully weighed against the risk of anaphylaxis.

Drug rash with eosinophilia and systemic symptoms (DRESS) syndrome in childhood: a narrative review

Despite being rare, the Drug Rash with Eosinophilia and Systemic Symptoms (DRESS) syndrome is a serious, possibly fatal condition that may affect both adults and children who may be also burdened by delayed sequelae. It is an adverse drug reaction characterized by widespread skin involvement, fever, lymphadenopathy, visceral involvement, and laboratory abnormalities (eosinophilia, mononucleosis-like atypical lymphocytes). It is more frequently triggered by anticonvulsants, sulphonamides, or antibiotics, the latter being responsible for up to 30% of pediatric cases. The disease typically develops 2-8 weeks after exposure to the culprit medication, with fever and widespread skin eruption; mild viral prodromes are possible. Unfortunately, diagnosis is challenging due to the absence of a reliable test; however, a score by the European Registry of Severe Cutaneous Adverse Reactions (RegiSCAR) allows to classify suspect patients into no, possible, probable, or definite DRESS cases. Moreover, rapid-onset DRESS syndrome has been described in recent years. It affects children more often than adults and differs from the most common form because it appears ≤15 days vs. >15 days after starting the drug, it is usually triggered by antibiotics or iodinated contrast media rather than by anticonvulsants and has a higher presence of lymphadenopathy. Differential diagnosis between rapid-onset antibiotic-driven DRESS syndrome, viral exanthems, or other drug eruptions may be challenging, but it is mandatory to define it as early as possible to start adequate treatment and monitor possible complications. The present review reports the latest evidence about the diagnosis and treatment of pediatric DRESS syndrome.

Management of coronavirus disease 2019 vaccine-induced cutaneous complications: A comprehensive literature review

Despite the numerous reports of cutaneous manifestations associated with vaccines for coronavirus disease 2019 (COVID-19), the relationship between COVID-19 vaccines and cutaneous side effects remains unevaluated. In this review, we examine these manifestations and their management. Reported dermatoses included injection-site reaction (early and delayed), type I allergic reaction, morbilliform eruption, pityriasis rosea, Sweet syndrome, lichen planus, psoriasis, herpes zoster reactivation, erythema multiforme, Stevens-Johnson syndrome, and toxic epidermal necrolysis (TEN). The most common COVID-19 vaccination-related cutaneous manifestations are delayed local reactions, approximately 66% of which are associated with the Moderna vaccine, and 33% with the Pfizer vaccine. Aside from mild injection-site reactions, severe reactions include anaphylaxis and TEN. Most reactions, except for Stevens-Johnson syndrome and anaphylaxis, though unpredictable and unpreventable are mild and can be treated symptomatically. Findings from this review should allow primary care physicians and dermatologists to reach faster diagnosis and initiate prompt intervention.

Hypersensitivity to Non-Steroidal Anti-Inflammatory Drugs on a pediatric Portuguese cohort

Summary

Background. Non-steroidal anti-inflammatory drugs (NSAID)/analgesics (paracetamol) are among the most common causes of drug hypersensitivity reactions in children, with a reported prevalence of around 0.3% in the pediatric population. Paracetamol and ibuprofen are the most commonly reported culprits in the pediatric population. Our objective was to describe the allergy workup to NSAID/paracetamol of a pediatric population monitored in an allergy outpatient clinic. Methods. Retrospective observational study by consulting the medical records of patients evaluated in a pediatric outpatient clinic with history of NSAID/paracetamol, between January 2016 to August 2022. Results. A total of 43 patients have been evaluated for NSAID/paracetamol suspected allergy: 53.5% females, mean age of 9.8 ± 5.1 years, 47.7% atopic. The drugs reported as culprits were: ibuprofen (75.6%), paracetamol (17.8%), metamizole (4.4%) and naproxen (2.2%) and clinical manifestations were mainly urticaria/angioedema and maculopapular exanthema. Skin tests were performed in 7 patients: paracetamol (n = 5) and metamizole (n = 2), which were all negative. Fourty-six drug provocation tests were performed: 28 with the culprit drug and 18 with an alternative one; only 2 were positive (ibuprofen - culprit NSAID group): one immediate periorbital angioedema and one delayed lip edema with oropharyngeal tightness. Conclusions. The investigation of allergy to NSAID/paracetamol in children remains a challenge. In our population, ibuprofen was the most common NSAID reported. There were only 2 (4.3%) mild reactions on DPT. We could allow the use of the culprit NSAID/analgesic in 11 patients and an alternative one in 9 patients. This study highlights the importance of DPT in children for a correct diagnosis of NSAID hypersensitivity and selection of an alternative drug.

In vitro diagnostic testing for drug allergy in children

Diagnosing Drug Hypersensitivity Reactions (DHRs) could be a complicated process especially in children, since allergic-like manifestation at this age is more often the expression of concomitant infections rather than a actual DHRs. In vivo tests are usually suggested as a first step; however, prick and intradermal tests could be painful and have shown different sensitivity and specificity among published studies. In some cases, in vivo tests such as Drug Provocation test (DPT) could be even contraindicated. Therefore, the need for in vitro testing is compelling, to add useful information along the diagnostic pathway and to limit the need of DPT. In this review, we analyze the different types of in vitro tests, focusing on those used more widely such as specific IgE and on those that are still for research settings, such as basophil activation test and lymphocyte transformation test, but that have shown some useful diagnostic potential.

Primary care doctors' attitude towards drug allergy in Portugal: a questionnaire

Summary

Background. The aim of the study was to learn about perception of drug allergy by general practitioners (GP) from continental Portugal, identify difficulties and educational needs for its management. Methods. A total of 372 answers were obtained. A questionnaire was addressed to GPs. Results. The most commonly identified drugs were antibiotics for 65.3% of the GPs and skin was the most commonly affected organ for 65.8%. Drug allergy was considered as very important in clinical practice by 73.7%, but difficulties in recognizing it were stated by 70.2%. Further education in this field wouldbe welcome by 97.8% of the doctors. The collaboration of Immunoallergology centers was considered non satisfactory by 39.8% of GPs and 45.7% of them stated that two-thirds of the suspected reactions were not investigated. Conclusions. These points deserve consideration in future health educational and organizational strategies.

Pharmacist-led improvement in perioperative antibiotic selection for patients with a penicillin allergy label

DISCLAIMER

In an effort to expedite the publication of articles, AJHP is posting manuscripts online as soon as possible after acceptance. Accepted manuscripts have been peer-reviewed and copyedited, but are posted online before technical formatting and author proofing. These manuscripts are not the final version of record and will be replaced with the final article (formatted per AJHP style and proofed by the authors) at a later time.

PURPOSE

Surgical patients with a penicillin allergy label (PAL) are less likely to receive β-lactams for surgical site infection (SSI) prophylaxis and more likely to receive second-line antibiotics, which may increase the risk of SSI, drug toxicities, and associated costs. We assessed the impact of implementing a pharmacist-led quality improvement project to increase the use of cefazolin as a first-line agent in this population.

SUMMARY

After implementation of a pilot project in December 2021, all patients with a PAL and orders for preoperative antibiotics were risk stratified into high- or low-risk categories by a pharmacist. For the low-risk group, cefazolin was recommended. For the high-risk group, cefazolin was avoided and a second-line agent was administered. Our analysis compared 422 preintervention patients (August 15 to November 15, 2021) to 492 postintervention patients (December 15 to March 15, 2022). During the postintervention period, β-lactam usage increased (from 12.6% to 37.8%, P < 0.001), while usage of vancomycin (45.5% vs 29.5%, P < 0.001) and other second-line antibiotics (87.4% vs 62.2%, P < 0.001) declined. There were no adverse reactions reported in the preintervention cohort, with 2 potential adverse reactions reported after the intervention (0% vs 0.4%, P = 0.190). Medication costs based on claims data were 50% to 80% lower for patients receiving cefazolin.

CONCLUSION

In our cohort, a pharmacy-led antibiotic selection algorithm for patients with a PAL receiving perioperative antimicrobial prophylaxis resulted in increased use of β-lactam antibiotics, decreased use of second-line antibiotics, and decreased costs without a significant change in the incidence of adverse reactions.

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.

Viral infections and drug hypersensitivity

Virus infections and T-cell-mediated drug hypersensitivity reactions (DHR) can influence each other. In most instances, systemic virus infections appear first. They may prime the reactivity to drugs in two ways: First, by virus-induced second signals: certain drugs like β-lactam antibiotics are haptens and covalently bind to various soluble and tissue proteins, thereby forming novel antigens. Under homeostatic conditions, these neo-antigens do not induce an immune reaction, probably because co-stimulation is missing. During a virus infection, the hapten-modified peptides are presented in an immune-stimulatory environment with co-stimulation. A drug-specific immune reaction may develop and manifest as exanthema. Second, by increased pharmacological interactions with immune receptors (p-i): drugs tend to bind to proteins and may even bind to immune receptors. Without viral infections, this low affine binding may be insufficient to elicit T-cell activation. During a viral infection, immune receptors are more abundantly expressed and allow more interactions to occur. This increases the overall avidity of p-i reactions and may even be sufficient for T-cell activation and symptoms. There is a situation where the virus-DHR sequence of events is inversed: in drug reaction with eosinophilia and systemic symptoms (DRESS), a severe DHR can precede reactivation and viremia of various herpes viruses. One could explain this phenomenon by the massive p-i mediated immune stimulation during acute DRESS, which coincidentally activates many herpes virus-specific T cells. Through p-i stimulation, they develop a cytotoxic activity by killing herpes peptide-expressing cells and releasing herpes viruses. These concepts could explain the often transient nature of DHR occurring during viral infections and the often asymptomatic herpes-virus viraemia after DRESS.

[ANTIMICROBIAL ALLERGY ASSESSMENT DURING PREGNANCY FOR APPROPRIATE ANTIMICROBIAL USE AT DELIVERY]

BACKGROUND

Avoidance of suspect drugs based solely on a history of drug allergy is detrimental to disease outcomes. Many antimicrobial allergy labels are not usually true allergy. Some studies have demonstrated that antimicrobial allergy assessments can be safely performed on pregnant women. The purpose of this study was to examine the usefulness of antibiotic allergy assessment during pregnancy in Japan.

METHODS

We reviewed pregnant women who reported antimicrobial allergies and were referred to the allergy center. Allergists conducted an interview and skin test and selected antibiotics that could be used at delivery.

RESULTS

Twenty-four pregnant women were referred to as having antimicrobial allergies. Most of the suspected antimicrobials were cephalosporin (13 cases, 52%) and penicillin (9 cases, 36%). Five women were ruled out only by our interviews. Of the remaining 20 cases, 10 were immediate type, 6 were non-immediate type, and 4 were unknown. All 21 pregnant women who needed antimicrobials were able to use the first-line drugs (β-lactam antimicrobials) at the time of delivery. No surgical site infections or allergic reactions were observed.

CONCLUSION

Pregnant women with antimicrobial allergy labels could be evaluated by antimicrobial allergy assessment during pregnancy, and first-line antimicrobials were safely and properly used at delivery.

Diagnostic Value of Oral Provocation Tests in Drug Hypersensitivity Reactions Induced by Nonsteroidal Anti-Inflammatory Drugs and Paracetamol

Oral drug provocation tests (DPT) are the basic diagnostic tool for the detection of hypersensitivity to non-opioid analgesics and for selecting a safe alternative for a patient. They are of great practical importance due to their common use, but the data on the follow-up of patients after negative DPT are still very scarce. We examined the further fate of 164 such adult patients after negative NSAID or paracetamol tests and analyzed which excipients in the studied drugs they could be exposed to after the diagnostic workup. A structured medical interview was performed 32.9 months (mean) after the provocation tests. Of the 164 patients, 131 (79.9%) retook the tested drug and 12 developed another hypersensitivity reaction, giving the estimated negative predictive value of 90.8%. These reactions were induced by acetylsalicylic acid, paracetamol, meloxicam, and diclofenac, and were clinically similar to the initial ones (most commonly urticaria and angioedema). There are 93 generics of these drugs on the local market, containing a total of 33 excipients for which hypersensitivity reactions have been reported. All available generics contain such excipients. Thirty-one patients (20.1%) did not take the previously tested drug again, most often because it was not needed or because they were afraid of another reaction. DPT with analgesics has a high diagnostic performance. A minority of patients had relapsed after reexposure. One of the underestimated reasons for this may be drug excipients provoking a reaction, so it is advisable to use exactly the same medical product that has been negatively tested. Many patients avoid reexposure to a given drug, despite negative tests, therefore very reliable patient education in connection with DPT is highly needed.

Pathology of drug hypersensitivity reactions and mechanisms of immune tolerance

Immune-mediated type IV adverse drug reactions are idiosyncratic in nature, generally not related to the primary or secondary pharmacology of the drug. Due to their complex nature and rarity, these iatrogenic reactions are seldom predicted or encountered during preclinical/early clinical development stages, and often precipitate upon exposure to wider populations (i.e. phase III onwards). They confer a burden on the healthcare sector in both a clinical and financial sense presenting a severe impediment to the drug discovery and development process. Research over the past 50 years has improved our understanding of these reactions markedly as both in vitro and in vivo studies have placed the role of the immune system, in particular; drug-responsive T cells, firmly in the spotlight as the mediators of these reactions. Indeed, the role of different populations of T cells in adverse events and the interaction of drug molecules with HLA proteins expressed on the surface of antigen-presenting cells is of considerable interest. Herein, this review examines the pathways of immune-mediated adverse events including the various T cell subtypes implicated and the mechanisms of T cell activation. Additionally, we address the enigma of immunological tolerance and explore the role tolerance plays in determination of susceptibility to such adverse events even in individuals carrying immunogenic liabilities.

A striking presentation of pustular Sweet syndrome induced by trimethoprim-sulfamethoxazole

We describe a strikingly robust presentation of trimethoprim-sulfamethoxazole (TMP-SMX)-induced pustular Sweet syndrome and discuss how to distinguish it from iododerma and other neutrophil-rich conditions. A review of the literature indicates that TMP-SMX-induced Sweet syndrome (SS) may have higher rates of neutrophilia and greater ocular, mucosal, and musculoskeletal involvement compared to SS from other drugs. Recognizing these features and identifying the offending agent are critical for correctly diagnosing TMP-SMX-induced SS in a timely manner.

Infantile Stevens Johnson syndrome and toxic epidermal necrolysis: A systematic review of clinical features and outcomes in children ages 12 months and under

BACKGROUND/OBJECTIVES

Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are life-threatening mucocutaneous hypersensitivity reactions that carry significant morbidity and mortality. While clinical features are well documented in adult and pediatric patients, infantile cases are rarely reported. Our objective was to synthesize clinical features and outcomes in this population.

METHODS

A literature search was performed from three large databases (PubMed, EMBASE, and Web of Science) to systematically identify reports of SJS/TEN in the infantile period (defined as less than 12 months of age) between 1962 and 2019. Cases determined to represent SJS/TEN based on defined criteria were included. Each case was scored based on Quality Rating Scheme for Studies and Other Evidence. The initial search yielded 4856 publications, of which 19 (n = 26) met final inclusion criteria.

RESULTS

All cases for which body surface area (BSA) involvement was available or able to be approximated (n = 18/26) met criteria for TEN. All cases (n = 26) had mucous membrane involvement, with the oral mucosa most commonly affected (85.7%). Mortality was high within our population with 39.1% of infants expiring, 77.8% secondary to bacterial sepsis. The most common triggers were medications (52.4%), infections (33.3%), and vaccinations (14.3%).

CONCLUSIONS

This review highlights several unique clinical findings amongst infants with SJS/TEN, including increased BSA involvement, higher rates of bacterial sepsis, and higher mortality rates compared to older children and adults. Infants are more likely to present as TEN over SJS. More research is needed to identify triggers, successful treatments, and specific outcomes in this population.

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.

Chronic Spontaneous Urticaria in Hong Kong: Clinical Characteristics, Real-World Practice and Implications for COVID-19 Vaccination

PURPOSE

The real-world management and clinical characteristics of chronic spontaneous urticaria (CSU) in Hong Kong and its implications for coronavirus disease 2019 (COVID-19) vaccination are unknown. We investigated the clinical characteristics of patients with CSU and the role of an immunologist-led Urticaria Clinic as well as the impact of CSU on COVID-19 vaccine uptake in Hong Kong.

METHODS

Longitudinal clinical data of 257 CSU patients were collected and analyzed. Association analyses were performed to identify the relationships between variables and factors associated with COVID-19 vaccine uptake.

RESULTS

After the immunologist review, the Weekly Urticaria Activity Score (UAS7) was significantly lower than baseline (median: 0.00 vs. 12.0, P < 0.001). Changes in UAS7 were significantly greater among patients with baseline UAS7 ≥ 16 compared to those with UAS7 < 16 (median: -24.0 vs. -2.00, P < 0.001). CSU patients had lower COVID-19 vaccination rates than the general population with only 176 (68.5%) and 165 (65.0%) receiving at least one dose and 2 doses of vaccination, respectively. The presence of concomitant suspected drug allergy was associated with lower COVID-19 vaccine uptake (odds ratio [OR], 0.47; P = 0.010), while regular pharmacological treatment was associated with higher COVID-19 vaccine uptake among CSU patients (OR, 3.79; P = 0.010).

CONCLUSIONS

A dedicated immunologist-led Urticaria Clinic may effectively improve CSU management and outcomes in Hong Kong.

HLA pharmacogenetic markers of drug hypersensitivity from the perspective of the populations of the Greater Middle East

Specific HLA associations with drug hypersensitivity may vary between geographic regions and ethnic groups. There are little to no data related to HLA-drug hypersensitivity on populations who reside in the Greater Middle East (GME), a vast region spanning from Morocco in the west to Pakistan in the east. In this review, the authors intended to summarize the significant HLA alleles associated with hypersensitive drug reactions induced by different drugs, as have been found in different populations, and to summarize the prevalence of these alleles in the specific and diverse populations of the GME. For example, HLA-B*57:01 allele prevalence, associated with abacavir-induced hypersensitivity, ranges from 1% to 3%, and HLA-DPB1*03:01 prevalence, associated with aspirin-induced asthma, ranges from 10% to 14% in the GME population. Studying pharmacogenomic associations in the ethnic groups of the GME may allow the discovery of new associations, confirm ones found with a low evidence rate and enable cost-effectiveness analysis of allele screening before drug use.

Managing the ADR of Stevens-Johnson syndrome/toxic epidermal necrolysis

INTRODUCTION

Stevens-Johnson syndrome and toxic epidermal necrolysis are severe, life-threatening adverse drug reactions that are collectively known as epidermal necrolysis. The abrupt detachment of the skin and mucositis results in systemic complications such as fluid and electrolyte disturbances, hypothermia, sepsis, organ failure, and death. Management is multidisciplinary and complex.

AREAS COVERED

This present article reviews the principles and best practices in the care of patients with epidermal necrolysis. These include having prompt admissions to optimal care facilities, coordinated specialized care during the acute phase, as well as long-term follow-up to manage chronic sequelae.

EXPERT OPINION

Patients with epidermal necrolysis should be managed in specialized/reference centers that are experienced with the management of the disease. Multi-disciplinary supportive care remains the cornerstone. Current evidence precludes definitive recommendation on any immunomodulatory agent as treatment. Long-term follow-up is required in order to diagnose and treat any chronic sequelae.

Incidence of immediate allergic reactions to mRNA COVID-19 vaccines in adults with drug allergies and other allergic disorders

Concerns have been raised about allergic reactions to messenger ribonucleic acid (mRNA) coronavirus disease 2019 (COVID-19) vaccines. A history of allergic reactions, including anaphylaxis to drugs, has been frequently reported in individuals with anaphylaxis to mRNA vaccines. To estimate the rate of immediate allergic reactions in patients with a history of drug allergy or other allergic disorders. We included adult patients who had received at least 1 dose of an mRNA COVID-19 vaccine at the Special Hospital for Pulmonary Diseases between March 1, 2021, and October 1, 2021, and who reported a history of drug allergy or other allergic diseases (asthma, allergic rhinitis, atopic dermatitis, food or insect venom allergy, mastocytosis, idiopathic anaphylaxis, acute or chronic urticaria, and/or angioedema). Immediate allergic reactions, including anaphylaxis, occurring within 4 hours of vaccination were recorded. Six immediate allergic reactions were noted in the cohort of 1679 patients (0.36%). One patient experienced anaphylaxis (0.06%), which resolved after epinephrine administration, and the other reactions were mild and easily treatable. Most patients with a history of allergies can safely receive an mRNA COVID-19 vaccine, providing adequate observation periods and preparedness to recognize and treat anaphylaxis.

Linear Immunoglobulin a Bullous Dermatosis in Children

Linear Immunoglobulin A Bullous Disease (LABD) is a rare dermatosis whose pathomechanisms are not yet completely understood. LABD has different features characterizing adults and children in terms of potential triggers, clinical manifestations, and prognosis. The aim of the present study is to review all neonatal and pediatric cases of LABD and summarize the major characteristics. Childhood LABD is mainly idiopathic with a benign prognosis. Neonatal cases are difficult to differentiate from infectious diseases and usually have a poor prognosis. Drugs are one of the possible triggers that can activate autoimmune responses through antigen mimicry and epitope spreading as well as different stimuli (e.g., infections, inflammatory diseases, trauma). The gold standard for the diagnosis is based on direct immunofluorescence. Prognosis is generally favorable but often depends on the prompt dermatological diagnosis, treatment and follow-up guaranteed by a multidisciplinary team, including pediatricians for this group of age.

Drugs and Vaccines Hypersensitivity in Children with Mastocytosis

Mastocytosis, a heterogeneous mastcell disease, include three different entities: cutaneous mastocytosis, systemic mastocytosis (SM) and mast-cell sarcoma. Tryptase levels can differentiate cutaneous mastocytosis from SM. In mastocytosis, quick onset drug hypersensitivity reactions (DHRs) that are facilitated by mastcell mediators, are investigated in adults. Due to the limited number of children with mastcell disease and increased serum tryptase levels, the role of drugs in this age group is less studied. In this review, we critically assessed relevant papers related with immediate DHRs in children with mastocytosis and discuss practical issues of the management. In childhood mastocytosis, anaphylaxis is frequently idiopathic, and elevated level of basal tryptase, and high burden of disease may increase the risk. Among drugs, antibiotics, NSAIDs and opioids can potentially induce anaphylaxis, anyway avoidance should be recommended only in case of previous reactions. Moreover, vaccinations are not contraindicated in patients with mastocytosis. The risk of severe systemic reactions after drugs intake seems to be extremely low and in general lower in children than in adults. Anyway, studies on this topic especially focusing on children, are missing to state final recommendations.

Allergy clinic patients' drug hypersensitivity

BACKGROUND

Drug hypersensitivity reaction (DHR) is a common reason for an allergology con- sultation, during which it is not only necessary to gather a thorough medical history, but also to propose and perform diagnostic tests.

OBJECTIVES

The aim of the study was to retrospectively assess the patients with a profile of preliminary drug hypersensitivity diagnosis, the usefulness of NSAID hypersensitivity classifica- tion in outpatient practice, and to analyze the results of skin, provocation, and drug tolerance tests performed in Immunology and Allergy Clinic patients.

METHODS

Around 501 medical records of patients referred to the academic allergy outpatient clinic from 2011 to 2019, and had a preliminary drug hypersensitivity diagnosis were analyzed. The diagnostic and drug tolerance tests results carried out in 269 patients of the Clinic from 2009 to 2019 were then evaluated.

RESULTS

Among the patients referred due to suspected drug hypersensitivity, the majority (n=338, 67.5%) were believed to be hypersensitive to NSAIDs and antibiotics (n=272, 54.3%). In patients with hypersensitivity to NSAIDs, the mixed pattern was the most prevalent (n=73, 21.6%), followed by NECD (n=64, 18.9%) and NIUA (n=55, 16.3%). The second most common drug causing DHR were the antibiotics, mainly β-lactams (n=160, 58.8%), followed by macrolides (n=35, 12.9%). In hypersensitivity caused due to β-lactams, the delayed form was predominant (n=24, 15%) with manifested skin symptoms (n=74, 46.3%). Non-steroidal anti-inflammatory drugs (n=21, 42.9%), followed by antibiotics (n=11, 22.5%) were the commonest causes of ana- phylaxis, as reported by 49 patients.

CONCLUSION

The study shows that a majority of patients with suspected drug hypersensitivity can be classified under the hypersensitivity umbrella based on their medical history, which is the basis for further diagnostic process.