Desensitization in delayed drug hypersensitivity reactions -- an EAACI position paper of the Drug Allergy Interest Group

Hypersensitivity reaction to Abiraterone, successful desensitization protocol in prostate cancer patient

INTRODUCTION

In prostate cancer, androgens are key in the growth of both normal prostate and cancer cells. Abiraterone acetate inhibits CYP17, an important target in prostate cancer given its central role in the production of adrenal and tumor-derived androgens. Although abiraterone is generally well tolerated, common adverse effects such as hypertension, hypokalemia, and hepatotoxicity have been reported.

CLINICAL CASE

We present the case of an 83-year-old Mexican man with high-volume EC IV prostate cancer resistant to castration, orchiectomy, and bone, liver, and lung metastases. First-line treatment with the CHAARTED scheme was indicated, by patient decision refuse chemotherapy treatment. On the fourth day of starting treatment, he developed pruritic erythematous macular skin lesions and urticaria on the posterior chest that resolved spontaneously. A generalized erythematous and pruritic maculopapular rash appeared 12 days after starting abiraterone, for which she was referred to allergies.

MANAGEMENT AND RESULTS

An oral provocation test was performed for two days, presenting localized macular lesions eight hours after the administration of abiraterone. An oral desensitization protocol was carried out for ten days in which no hypersensitivity reactions were observed, thus achieving the successful administration of abiraterone.

Antibiotic prophylaxis in immunosuppressed patients - Missed opportunities from trimethoprim-sulfamethoxazole allergy label

Trimethoprim-sulfamethoxazole (TMP-SMX) is a broad spectrum antibiotic in use for more than 50 years. It has an important indication as first line agent in the prophylaxis of opportunistic infections, particularly Pneumocystis jirovecii pneumonia (PJP), in immunosuppressed patients. For those who have a history of allergy or severe intolerance to TMP-SMX, pentamidine, dapsone or atovaquone may be substituted; however there is evidence that TMP-SMX offers superior coverage for PJP, toxoplasmosis, and nocardiosis. Compared to pentamidine, it has the added benefit of cost-effectiveness and self-administration as opposed to required hospital attendance for administration. Many patients who report a history of allergy or adverse reaction to TMP-SMX (or "sulfur allergy") will be found not to be allergic; and even those who are allergic may be able to be desensitized. The evaluation and, where appropriate, removal of TMP-SMX allergy label enables the use of TMP-SMX for prophylaxis against opportunistic infections. This is a cost-effective intervention to optimize antimicrobial prescribing and reduce the risk of opportunistic infections in immunosuppressed patients.

Desensitization in patients with hypersensitivity to platinum and taxane in gynecological cancers

BACKGROUND

Exposure to paclitaxel and carboplatin has the risk of developing hypersensitivity reactions (HSRs), which could necessitate using less effective treatments to avoid anaphylaxis. Desensitization to platinum and taxane HSRs can be used to complete chemotherapy according to the standard regimen; therefore, this study investigated rates and benefits of successful desensitization in patients with gynecologic cancers (GC).

METHODS

We collected data from 241 patients with GC who had at least one cycle of platinum or taxane chemotherapy. The rate of HSRs and successful desensitization were evaluated, and an outcome analysis was conducted.

RESULTS

The rate of HSRs to platinum and taxane was 6.39% and 13.07%, respectively. We observed a 100% success rate of desensitization in our cohort. Patients with HSR were significantly younger (57.1 vs. 64.9 years, p = 0.030) in the taxane cohort. Importantly, the overall survival (OS) of patients with platinum and taxane HSRs who underwent desensitization was comparable to that of patients with no HSRs (platinum vs. controls; median OS 60.36 vs. 60.39 months, p = 0.31; taxane vs. controls; OS 80.29 vs. 60.00 months, p = 0.59).

CONCLUSION

Thus, we show that desensitization for platinum and taxane HSRs is safe and effective, resulting in an outcome that is well comparable to patients without HSR. Based on these observations, desensitization procedures might be considered as standard of care before switching to less effective treatment for patients with GC.

Lack of Suspicion of Dapsone Hypersensitivity Syndrome in a Leprosy Patient: Case Report with Fatal Outcome

Background

Dapsone is an antibiotic used in the management of leprosy. Following the worldwide adoption of the dapsone-containing multidrug therapy for treating leprosy, an upsurge in the reported frequency of dapsone hypersensitivity syndrome (DHS) has been observed. DHS is associated with a high fatality rate among patients from low-resourced settings and patients with syndrome-associated hepatitis.

Case Presentation

This is a case of a Ghanaian male who, while being treated for leprosy with the multidrug therapy, developed exfoliative dermatitis and signs of liver damage, 6 weeks after treatment initiation. He was managed for dapsone-related exfoliative dermatitis and infectious causes of liver damage were investigated. However, the patient's condition rapidly deteriorated with a fatal outcome despite discontinuation of dapsone. DHS was only considered as a differential diagnosis postmortem.

Conclusion

This case highlights the importance of having a high index of suspicion for DHS in all patients on dapsone and the need for a thorough workup for all leprosy patients who present with exfoliative dermatitis and signs of liver involvement within the latency period of the syndrome, especially in low resource settings. Furthermore, it stresses the need for prompt and appropriate treatment as DHS can quickly become fatal in such settings.

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.

Anaphylactic reaction to carboplatin diagnosed by skin testing-a reliable tool in platinum-based immediate-type hypersensitivity reactions

Immediate-type hypersensitivity reactions (IHRs) to carboplatin (CA) are most commonly reported in ovarian cancer patients. A 54-year-old woman with stage IV melanoma suffering from metastasis in the entire right lower extremity was presented to our allergy outpatient clinic for diagnostic work-up due to an anaphylactic reaction with palmoplantar erythema, conjunctivitis along with facial erythema, and an incipient decrease in blood pressure during a chemotherapy regimen with dacarbazine and carboplatin upon re-administration. A subsequently carried out allergological work-up with skin testing (ST) revealed CA to be the culprit drug, whereas cisplatin (CI) was confirmed to be a safe alternative for the patient for following treatments. Here, we report a case of an IHR to carboplatin in a melanoma patient, with CI serving as a safe alternative diagnosed by skin testing.

Research progress on desensitization of hypersensitivity reaction to iodinated contrast media

Desensitization therapy for iodinated contrast media (ICM) aims to induce drug tolerance in patients with a history of severe allergic reactions to ICM in a short time. Currently, there is no widely accepted consensus on inducing desensitization to avoid severe allergic responses to ICM. The clinically successful cases have shown that prophylactic use of antihistamines and glucocorticoids can increase the desensitization effect; repeatedly desensitizing and gradually increasing the dose can be conducive to establishing better tolerance to ICM. Most desensitization effects, including stress resistance, can endure 24-48 h. The mechanisms of desensitization therapy remain unclear, the initial dose, administration interval and dose gradient are largely based on clinical experiences and the reaction of patients. This article reviews the current research progress on ICM-related allergies, desensitization methods and related mechanisms, as well as the benefits and hazards of desensitization, to provide a reference for desensitization treatment of hypersensitivity to ICM .

Incidence and Clinical Impact of Endovenous Glue-Induced Hypersensitivity Among Patients Who Underwent Endovenous Cyanoacrylate Ablation Procedures: A Registry-Based Cohort Study

BACKGROUND

The characteristics of endovenous glue-induced hypersensitivity (EGIH) remain unclear.

OBJECTIVE

To assess the clinical impacts on patients with EGIH after endovenous cyanoacrylate-glue ablation (CA).

MATERIALS AND METHODS

A prospectively designed endovenous CA-specific registry was created, and a total of 335 limbs from 173 patients who underwent endovenous CA were enrolled for a cohort study.

RESULTS

Symptomatic EGIH was observed in 55 (31.8%) patients. Beyond the target vein area, systemic side effects were noted in 5.8% of the treated patients after CA. The median onset time was 13 postoperative days (range: 1-35 days). The median duration was 7 days, but about 10.9% of the affected patients experienced symptoms lasting longer than 4 weeks. In the EGIH and non-EGIH groups, significant improvements in venous clinical severity score and Chronic Venous Insufficiency Quality of Life Questionnaire-14 scores were observed 3 months postoperatively. The development of EGIH did not affect the postoperative patient-reported satisfaction scores ( p = .524).

CONCLUSION

EGIH is observed in a substantial proportion of patients. The side effects do not affect the clinical outcomes and patient-reported outcome measures. Further studies are required on the detailed pathogenesis and definition of EGIH.

Desensitization in children allergic to drugs: Indications, protocols, and limits

Any drug can potentially induce a hypersensitivity reaction. If after the allergological work-up the drug hypersensitivity reaction is confirmed, in most cases, the simple avoidance of the culprit drug and a suggestion of an unrelated alternative is enough. However, there are circumstances where the choice to stop the treatment affects the survival, the safety and/or the quality of life of the patient and the global outcome of the disease in question. When this occurs, drug desensitization can be the answer and should not be viewed as an extravagance, nor the pediatric age should be considered a contraindication. Drug desensitization in children can be safely and successfully performed, having a positive impact on the survival and overall prognosis. In general, the indications for DDS are the same in adults as in children. However, in this age group there are specificities that this paper aimed to describe, reviewing the mechanisms behind drug hypersensitivity and rapid drug desensitization, types of protocols, indications, and contraindications, as well as several technical aspects that are specific to the pediatric age.

Desensitization protocol to lenalidomide: An effective and safe treatment modality for delayed hypersensitivity-induced rash in patients with multiple myeloma

INTRODUCTION AND OBJECTIVES

Lenalidomide is considered a standard of care in multiple myeloma (MM) Some MM patients will develop delayed hypersensitivity to lenalidomide, which can lead to treatment discontinuation. Desensitization to lenalidomide can help these patients to complete treatment courses. Here, we aimed to review lenalidomide-treated MM patients who developed delayed hypersensitivity-induced rash and were treated with desensitization.

METHODS

A retrospective analysis of medical files of MM patients, who were desensitized to lenalidomide due to delayed hypersensitivity rash. Patients were treated between 2018 and 2022 at Hadassah Medical Center, Jerusalem, Israel.

RESULTS

Search of patients yielded 16 patients that underwent desensitization to lenalidomide within the study period. The desensitization protocol consisted of a slow, 3-week-long protocol with lenalidomide's target doses of 10, 15, and 25 mg/day. Of the 16 patients, 10 (62.5%) succeeded to complete the protocol and thus were able to complete lenalidomide treatment cycles. One patient with unsuccessful desensitization was subsequently treated with first-generation IMiD thalidomide, with no rash appearing. None of the patients that were treated with desensitization had severe immune-mediated or non-dermatological adverse reactions.

CONCLUSIONS

Desensitization to lenalidomide is safe and effective. Discontinuation of lenalidomide in MM patients with delayed hypersensitivity and no contraindication to desensitization should be discouraged. Collaboration between hematologists and allergists is needed.

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.

Tuberculosis treatment-related lichenoid drug eruptions

Tuberculosis is one of the leading causes of death from infectious diseases in adults worldwide. Drug hypersensitivity in tuberculosis is an important problem affecting the treatment process. Although treatment is started with isoniazid, rifampicin, ethambutol, and pyrazinamide in drug-sensitive tuberculosis patients, it may not always be continued in this way. When hypersensitivity develops under antituberculosis treatment, type 4 hypersensitivity is the most common, and maculopapular drug eruption develops as a subgroup. Lichenoid drug eruption is very rare. We present our case who was diagnosed with pulmonary tuberculosis, who developed lichenoid drug eruption while receiving treatment, and whose treatment was completed by giving the new regimen with successful desensitization.

Attenuation of Human Growth Hormone-Induced Rash With Graded Dose Challenge

Adult growth hormone (GH) deficiency is rare and requires replacement with extrinsic/synthetic injection. GH hypersensitivity has been reported; specifically, atopic patients may develop rashes from somatotropin therapy. Allergic and non-allergic skin reactions to recombinant human GH are uncommon and infrequently reported. We describe a graded-dose challenge with intravenous Norditropin® in a 65-year-old atopic adult woman who developed a severe whole-body rash with Norditropin FlexPro® administration on several occasions but was negative on skin-prick testing to Norditropin® percutaneously and intradermally, but the patch testing was positive for gold and nickel.

The patient was registered as a direct admission to the emergency room at a university hospital for a rapid antigen coronavirus disease 2019 (COVID-19) testing after having received two COVID-19 vaccinations and re-testing four months after vaccination. She was then directly admitted to a non-COVID-19 intensive care unit with direct bedside supervision by a registered nurse and a physician board certified in internal medicine, allergy/immunology, and pulmonary diseases. The patient brought a Norditropin® pen which our pharmacy team attached to a compatible syringe for dilutions. A graded dose challenge at a final dosage of 0.1 mL was performed and the patient was monitored for allergic and other adverse drug reactions, which did not occur. At the time of writing this case report, the patient has been maintained on Norditropin FlexPro® 0.1 mL and has not experienced any adverse reactions, including recurrent skin eruptions.

The case presented is the first to describe a patient who successfully tolerated a graded dose challenge of an adult patient to GH replacement therapy (as Norditropin®) under supervision in an intensive care unit, whereas prior to reporting of this case, a graded dose challenge to GH replacement therapy had only been successfully performed in a child using another formulation of somatotropin (Humatrope®). Hence, this case lends support that graded dose challenge with somatotropin analogs may be considered for patients with isolated GH deficiency such as in the case presented here.

Antibiotic Allergy De-Labeling: A Pathway against Antibiotic Resistance

Antibiotics are one of the most frequently prescribed drugs. Unfortunately, they also are the most common cause for self-reported drug allergy, limiting the use of effective therapies. However, evidence shows that more than 90% of patients labeled as allergic to antibiotics are not allergic. Importantly, the label of antibiotic allergy, whether real or not, constitutes a major public health problem as it directly impacts antimicrobial stewardship: it has been associated with broad-spectrum antibiotic use, often resulting in the emergence of bacterial resistance. Therefore, an accurate diagnosis is crucial for de-labeling patients who claim to be allergic but are not really allergic. This review presents allergy methods for achieving successful antibiotic allergy de-labeling. Patient clinical history is often inaccurately reported, thus not being able to de-label most patients. In vitro testing offers a complementary approach but it shows limitations. Immunoassay for quantifying specific IgE is the most used one, although it gives low sensitivity and is limited to few betalactams. Basophil activation test is not validated and not available in all centers. Therefore, true de-labeling still relies on in vivo tests including drug provocation and/or skin tests, which are not risk-exempt and require specialized healthcare professionals for results interpretation and patient management. Moreover, differences on the pattern of antibiotic consumption cause differences in the diagnostic approach among different countries. A multidisciplinary approach is recommended to reduce the risks associated with the reported penicillin allergy label.

A new strategy of desensitization in mucopolysaccharidosis type II disease treated with idursulfase therapy: A case report and review of the literature

Mucopolysaccharidosis type II (MPS II) is a multisystemic lysosomal storage disorder caused by deficiency of the iduronate 2-sulfatase enzyme. Currently, enzyme replacement therapy (ERT) with recombinant idursulfase is the main treatment available to decrease morbidity and improve quality of life. However, infusion-associated reactions (IARs) are reported and may limit access to treatment. When premedication or infusion rate reductions are ineffective for preventing IARs, desensitization can be applied. To date, only two MPS II patients are reported to have undergone desensitization. We report a pediatric patient with recurrent IARs during infusion successfully managed with gradual desensitization. Our protocol started at 50% of the standard dosage infused at concentrations from 0.0006 to 0.06 mg/ml on weeks 1 and 2, followed by 75% of the standard dosage infused at concentrations from 0.0009 to 0.09 mg/ml on weeks 3 and 4, and full standard dosage thereafter, infused at progressively increasing concentrations until the standard infusion conditions were reached at 3 months. Our experience can be used in the management of MPS II patients presenting IARs to idursulfase infusion, even when general preventive measures are already administered.

Standards for practical intravenous rapid drug desensitization & delabeling: A WAO committee statement

Drug hypersensitivity reactions (DHRs) to intravenous drugs can be severe and might leave patients and doctors in a difficult position where an essential treatment or intervention has to be suspended. Even if virtually any intravenous medication can potentially trigger a life-threatening DHR, chemotherapeutics, biologics, and antibiotics are amongst the intravenous drugs most frequently involved in these reactions. Admittedly, suspending such treatments may negatively impact the survival outcomes or the quality of life of affected patients. Delabeling pathways and rapid drug desensitization (RDD) can help reactive patients stay on first-choice therapies instead of turning to less efficacious, less cost-effective, or more toxic alternatives. However, these are high-complexity and high-risk techniques, which usually need expert teams and allergy-specific techniques (skin testing, in vitro testing, drug provocation testing) to ensure safety, an accurate diagnosis, and personalized management. Unfortunately, there are significant inequalities within and among countries in access to allergy departments with the necessary expertise and resources to offer these techniques and tackle these DHRs optimally. The main objective of this consensus document is to create a great benefit for patients worldwide by aiding allergists to expand the scope of their practice and support them with evidence, data, and experience from leading groups from around the globe. This statement of the Drug Hypersensitivity Committee of the World Allergy Organization (WAO) aims to be a comprehensive practical guide on the technical aspects of implementing acute-onset intravenous hypersensitivity delabeling and RDD for a wide range of drugs. Thus, the manuscript does not only focus on clinical pathways. Instead, it also provides guidance on topics usually left unaddressed, namely, internal validation, continuous quality improvement, creating a healthy multidisciplinary environment, and redesigning care (including a specific supplemental section on a real-life example of how to design a dedicated space that can combine basic and complex diagnostic and therapeutic techniques in allergy).

Hypersensitivity to febuxostat in a patient with a previous allopurinol-induced Steven-Johnson syndrome: a case report of treatment with a slow desensitization protocol

BACKGROUND

We report thea case of a 43-year-old Chinese male with tophaceous gout who had been living in our country for some years.

CASE PRESENTATION

Previous treatments with allopurinol had induced Steven Johnson syndrome, dictating a switch to febuxostat 80 mg daily. After two years of treatment with febuxostat, he developed a diffuse maculopapular rash with severe itching. Rheumatologists stopped the febuxostat but the gout worsened over the following years despite of treatment with kalnicitrate and colchicine. Therefore, an allergy consultation was called for. A slow desensitization protocol with febuxostat was started, with a low oral dosage scheme to be increased up to 80mg/day. Febuxostat was prepared in a solid formulation by the pharmacist as pills, instead of the more frequently used liquid suspension.

CONCLUSION

The patient is currently receivinges febuxostat 80 mg, shows no side effects and his gout has improved. This is the first reported example of a successful desensitization protocol using a solid preparation of diluted febuxostat given as pills.

Use of Rapid Drug Desensitization in Delayed Hypersensitivity Reactions to Chemotherapy and Monoclonal Antibodies

Background:

Rapid drug desensitization (RDD) allows first-line therapies in patients with immediate drug hypersensitivity reactions (DHR) to chemotherapeutic drugs (ChD) and monoclonal antibodies (mAb). Desensitization in delayed drug reactions has traditionally used slow protocols extending up to several weeks; RDD protocols have been scarcely reported.

Patients and Method:

We retrospectively analyzed the patients referred to the Allergy Department, who had experienced a delayed DHR (&gt; 6 h) related to a ChD or mAb and underwent an RDD protocol. The rate of successful administration of the offending drug and the presence of adverse reactions were evaluated.

Results:

A total of 93 RDDs were performed in 11 patients (including 6 men and 5 women, with a median age of 61 years). The primary DHR were maculopapular exanthema (MPE) (8), generalized delayed urticaria (1), MPE with pustulosis and facial edema (1), and facial edema with desquamative eczema (1). The meantime for the onset of symptoms was 3 days (range 1–16 days). RDD was performed using a protocol involving 8–13 steps, with temozolomide (25), bendamustine (4), rituximab (9), infliximab (24), gemcitabine (23), and docetaxel (8), within 4.6–6.5 h. Sixteen breakthrough reactions were reported during the RDD (17.2 %) in 5 patients; all were mild reactions including 11 delayed and 5 immediate reactions. All patients completed their treatment.

Conclusions:

RDD is a potentially safe and effective procedure in patients suffering from delayed reactions to ChD and mAb. It allows them to receive full treatment in a short period, thereby reducing time and hospital visits.

Converter Phenotype: A New Profile That Is Not Exclusive to Taxanes

Introduction: Phenotype I hypersensitivity reactions are the most commonly reported drug reactions; however, precision medicine has made it possible to characterize new phenotypes. A recent communication proposed the existence of a “converter phenotype,” which would affect patients who present non-immediate hypersensitivity reactions and in subsequent exposures develop immediate hypersensitivity reactions. This study aimed to describe the clinical characteristics of converter phenotype reactions and their evolution during desensitization to chemotherapeutic drugs and monoclonal antibodies.

Methods: We retrospectively reviewed our database of patients undergoing desensitization to chemotherapy or biological agents and selected those with a converter phenotype. Demographic and clinical characteristics of the patients, the results of skin tests, tryptase and IL-6 levels, and desensitization outcomes were assessed.

Results: Of 116 patients evaluated, 12 (10.3%) were identified as having a converter phenotype. The median interval between drug exposure and reaction was 90.6 h (range 8-288 h). After the conversion, phenotype I was the most frequent (58.3%), followed by cytokine release reactions (33.3%). Fifty-one desensitizations were undertaken and all treatments completed, with 10 (19.6%) breakthrough reactions. No new changes in the phenotype were detected.

Conclusions: The symptoms of non-immediate drug hypersensitivity reactions may indicate the need for an early allergological evaluation to assess the risk of future immediate drug reactions. Clinical characteristics, skin test results, and biomarkers can help predict responses to rapid drug desensitization, guiding clinicians on how to optimize therapy delivery while maintaining patient safety.

'Practical management of suspected hypersensitivity reactions to anti-tuberculosis drugs.'

Tuberculosis (TB) is the commonest cause of death by a single infectious agent globally and ranks amongst the top ten causes of global mortality. The incidence of TB is highest in Low-Middle Income countries (LMICs). Prompt institution of, and compliance with, therapy are cornerstones for a favourable outcome in TB and to mitigate the risk of multiple drug resistant (MDR)-TB, which is challenging to treat. There is some evidence that adverse drug reactions (ADRs) and hypersensitivity reactions (HSRs) to anti-TB drugs occur in over 60% and 3-4% of patients respectively. Both ADRs and HSRs represent significant barriers to treatment adherence and are recognised risk factors for MDR-TB. HSRs to anti-TB drugs are usually cutaneous and benign, occur within few weeks after commencement of therapy and are likely to be T-cell mediated. Severe and systemic T-cell mediated HSRs and IgE mediated anaphylaxis to anti-TB drugs are relatively rare, but important to recognise and treat promptly. T-cell mediated HSRs are more frequent amongst patients with co-existing HIV infection. Some patients develop multiple sensitisation to anti-TB drugs. Whilst skin tests, patch tests and in vitro diagnostics have been used in the investigation of HSRs to anti-TB drugs, their predictive value is not established, they are onerous, require specialist input of an allergist and are resource-dependent. This is compounded by the global, unmet demand for allergy specialists, particularly in low income countries (LICs) / LMICs and now the challenging circumstances of the SARS-CoV-2 pandemic. This narrative review provides a critical analysis of the limited published evidence on this topic and proposes a cautious and pragmatic approach to optimise and standardise the management of HSRs to anti-TB drugs. This includes clinical risk stratification and a dual strategy involving sequential re-challenge and rapid drug desensitisation. Furthermore, a concerted international effort is needed to generate real-time data on ADRs, HSRs, safety and clinical outcomes of these interventions.

Immediate and Delayed Hypersensitivity Reactions to Beta-Lactam Antibiotics

Beta-lactam antibiotics are the most commonly reported drug allergy in adults and children. More than 95% of those with reported allergy labels to beta lactams are not confirmed when subjected to allergy testing. Beta lactam antibiotics are associated with a wide spectrum of immediate and delayed drug hypersensitivity reactions. The latency period to symptoms and clinical presentation aids in the causality assessment. Risk stratification based on diagnosis and timing then allows for appropriate management and evaluation. Skin prick testing, intradermal testing and oral challenge are well established for evaluation of immediate reactions. Delayed intradermal testing, patch testing and oral challenge can also be considered for evaluation of mild to moderate delayed reactions. Cross-reactivity between beta-lactams appears to be driven most commonly by a shared R1 side-chain. Standardized algorithms, protocols and pathways are needed for widespread implementation of a pragmatic and effective approach to patients reporting beta lactam allergy.

Eosinophilic Reaction at the Time of Catheter Insertion Predicts Survival in Patients Initiating Peritoneal Dialysis

INTRODUCTION

Despite excellent biocompatibility, insertion of silicone peritoneal dialysis (PD) catheters can induce minor foreign body reaction, affecting long-term patient outcomes. We evaluated the effect of eosinophilic reaction associated with PD catheter insertion on outcomes of patients initiating PD.

METHODS

Eosinophilic reaction to PD catheter insertion was defined as the ratio of peripheral blood eosinophil count at 1 week after insertion (E1W) to pre-insertion eosinophil count (E0), and the association of E1W/E0 with technique survival, peritonitis-free survival, and heart failure (HF)-related hospitalization-free survival was analyzed.

RESULTS

This retrospective cohort study included 116 patients (89 male patients) who underwent PD catheter insertion between January 2008 and June 2018 (61.3 ± 12.9 years). The follow-up duration was 46.2 (23.8-75.3) months. E1W was significantly higher than E0 (median, 333 vs. 234/μL, p < 0.001), with a median E1W/E0 of 1.54. The log-rank test showed that technique survival, peritonitis-free survival, and HF-related hospitalization-free survival were significantly better in patients with E1W/E0 < 1.54 than in those with E1W/E0 ≥ 1.54 (p = 0.002, <0.001, and <0.001, respectively). By the Cox regression analysis adjusted for age, sex, the Charlson comorbidity index, the estimated glomerular filtration rate, and the geriatric nutritional risk index, E1W/E0 remained a significant risk factor for technique failure, peritonitis, and hospitalization for HF (hazard ratio (HR) 1.68, p = 0.01; HR 2.19, p < 0.001; HR 2.15, p < 0.001, respectively).

CONCLUSION

Eosinophilic reaction at the time of PD catheter insertion is a novel marker that may predict outcomes in patients initiating PD.

Sulfonamide Hypersensitivity

Sulfonamides, particularly antimicrobial sulfonamides, have been implicated as a common cause of a spectrum of hypersensitivity reactions. Immediate IgE-mediated reactions have been reported but are much less common than delayed cutaneous reactions. Delayed cutaneous reactions range from benign exanthems to severe cutaneous reactions such as Stevens Johnson syndrome, toxic epidermal necrolysis, or drug reaction with eosinophilia and systemic symptoms. Sulfonamides can be subclassified as antimicrobial sulfonamides and non-antimicrobial sulfonamides, which are also distinguished by key structural differences, resulting in very low risk of cross-reactivity between these two subclasses. Immediate and delayed skin testing and in vitro testing remain limited as options in evaluating antimicrobial sulfonamide hypersensitivity. Drug challenges continue to play an important role in the evaluation of both immediate and delayed reactions, with a growing body of evidence for the safety of direct challenges regardless of human immunodeficiency virus infection status. While numerous "desensitization" protocols have been described for the management of antimicrobial sulfonamide hypersensitivity, there is limited evidence that such procedures are successful because of an induction of tolerance.

Altered levels of complement components associated with non-immediate drug hypersensitivity reactions

Nonimmediate drug hypersensitivity reactions (niDHRs) range from mild-type maculopapular exanthema (MPE) to severe type Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) with unentirely clarified pathogenesis. This study sought to explore whether complement components participated in niDHRs. The participants comprised of three groups as follows: MPE (n = 65), SJS/TEN (n = 13, contains 7 SJS, 2 SJS-TEN overlap and 4 TEN), and equal healthy controls (n = 78). Skin pathological changes were confirmed by hematoxylin and eosin staining. The mRNA and protein levels of complement components were assessed. In the MPE group, there were no alterations in complement components at the protein and mRNA levels found except for a decrease in factor H mRNA. In the SJS/TEN group, up-regulated levels of C3aR and C5aR mRNA and down-regulated factor H mRNA levels in blood were noted. A lower plasma protein level of C3, Factor H and a higher level of C3a, C5, C5a, C5b-9, Factor B (p < 0.05) were found in the SJS/TEN group compared with in the control (p < 0.05). In SJS/TEN skin lesions, indirect immunofluorescence assays showed positive specific staining for C5b-9, but not C3. Both C3aR and C5aR were positive staining in the SJS/TEN samples, while staining for C1q, mannose-binding lectin (MBL), Factor B, and Factor H were only weak or negative. The findings reported here are the first to define the expression profiles/extent of the presence of various complement components at the mRNA and protein levels in niDHRs, especially in SJS/TEN. These altered complement components might, at least in part, be integral to the mechanisms underlying the pathogeneses of SJS and TEN.

A new rapid titration protocol for lamotrigine that reduces the risk of skin rash

Objective

Lamotrigine is one of the most widely used antiepileptic drugs, but it has a critical issue of a skin rash if the starting dose is too high or the escalation rate is too rapid. We investigated the efficacy and safety of a novel and rapid titration protocol for lamotrigine that takes only 11 days to reach a daily dose of 200 mg.

Methods

We prospectively enrolled 33 adult patients (age 18‐85) who were diagnosed with epilepsy and started lamotrigine administration for the first time at a single tertiary hospital. Our new protocol starts with a subthreshold dose of the drug and then administers a stepwise‐incremental dose until reaching the full therapeutic dose within 11 days.

Results

Of 29 patients analyzed, only two (6.9%) experienced idiosyncratic skin rash before the first follow‐up visit at 2 weeks (±3 days). In addition, a therapeutic concentration was reached in more than 75% of studied patients after 2 weeks of lamotrigine administration.

Significance

These findings demonstrate the value of the novel tolerance induction protocol for lamotrigine, which could widen the available application of lamotrigine in various situations. However, this study is a preliminary study limited by a small number of patients and its nonrandomized and open‐label design, so the current protocol needs more rigorous clinical evaluations before the application to the real clinical setting.

Reintroduction of Antituberculous Drugs in Patients with Antituberculous Drug-Related Drug Reaction with Eosinophilia and Systemic Symptoms

BACKGROUND

Patients who suffered drug reaction with eosinophilia and systemic symptom (DRESS) during the treatment of tuberculosis (TB) commonly experience multidrug hypersensitivity reactions resulting in limited anti-TB drug choices. Therefore, reintroduction based on a desensitization protocol may be an option to resume anti-TB medication.

OBJECTIVE

To evaluate the outcomes and safety of resuming anti-TB drugs according to reintroduction methods in patients with anti-TB drug-related DRESS.

METHODS

A retrospective cohort of patients who had experienced anti-TB drug-related severe cutaneous adverse reactions from 2011 to 2017 was established from separate 5 institutions.

RESULTS

Anti-TB medication was resumed in 27 of 29 patients with anti-TB drug-related DRESS through complete changing regimen (n = 9), reintroduction by a graded challenge (n = 5), or reintroduction using a desensitization protocol (n = 13). Nine patients completely changed their anti-TB regimen to second-line TB drugs, but only 1 (11.1%) succeeded in maintaining new anti-TB drugs. The other 8 failed to take drugs due to the occurrence of hypersensitivity reactions to the newly introduced anti-TB drugs. Two (40.0%) of 5 patients who underwent graded rechallenges successfully completed anti-TB drugs, whereas 3 (60%) failed to resume anti-TB drugs due to the recurrence of hypersensitivity reactions. In 13 patients who resumed anti-TB drugs using a desensitization protocol, no one who underwent desensitization developed recurrence of DRESS; 11 (84.6%) eventually completed anti-TB treatment and 2 eventually failed to complete anti-TB treatment due to late-onset itching and drug-induced liver injury.

CONCLUSIONS

Resuming anti-TB medication based on desensitization protocols may be a safe and effective option for those with anti-TB drug-related DRESS.

Delayed hypersensitivity to antiepileptic drugs in children

BACKGROUND

Antiepileptic drugs (AEDs) are widely used for the treatment of epilepsy, but they can be associated with the development of mainly delayed/non-immediate hypersensitivity reactions (HRs). Although these reactions are usually cutaneous, self-limited, and spontaneously resolve within days after drug discontinuation, sometime HR reactions to AEDs can be severe and life-threatening.

AIM

This paper seeks to show examples on practical management of AED HRs in children starting from a review of what it is already known in literature.

RESULTS

Risk factors include age, history of previous AEDs reactions, viral infections, concomitant medications, and genetic factors. The diagnostic workup consists of in vivo (intradermal testing and patch testing) and in vitro tests [serological investigation to exclude the role of viral infection, lymphocyte transformation test (LTT), cytokine detection in ELISpot assays, and granulysin (Grl) in flow cytometry. Treatment is based on a prompt drug discontinuation and mainly on the use of glucocorticoids.

CONCLUSION

Dealing with AED HRs is challenging. The primary goal in the diagnosis and management of HRs to AEDs should be trying to accurately identify the causal trigger and simultaneously identify a safe and effective alternative anticonvulsant. There is therefore an ongoing need to improve our knowledge of HS reactions due to AED medications and in particular to improve our diagnostic capabilities.

Safe administration of drug desensitizations in pediatric patients

PURPOSE

Patients with certain types of allergic reactions to medication may safely receive the culprit medication through an elaborate allergy procedure called a drug desensitization. Nurses play a key role in this process which is only performed when a certain medication is absolutely indicated as optimal therapy. Nurses are instrumental in the planning stages of drug desensitizations for coordination of interdisciplinary care and anticipation of adverse effects. Thus, it is paramount that nurses performing this procedure understand the mechanism of desensitizations and have access to the resources needed to safely complete these procedures in pediatric patients.

CONCLUSION

Excellence in nursing clinical acumen and a detailed order set are essential to patient safety during dug desensitization. With the following methodology and coordination by nursing, we have had great success at Children's Hospital Los Angeles in over one hundred drug desensitizations in pediatric patients which allowed them to received first line therapies. We have created order sets from published references and years of clinical experience. The nursing care of adult patients undergoing drug desensitization procedures is well described in the literature but few resources exist for pediatric nurses. There is paucity of published nursing resources for pediatric drug desensitizations. Repeated PubMed searches for "pediatric drug desensitizations" in 2019-2020, revealed only one recent reference geared toward physicians.

PRACTICE IMPLICATIONS

With appropriate training, staffing, and coordination, drug desensitizations can be safely performed in pediatric patients with close observation by a multi-disciplinary team. The bedside nurse has a pivotal role as coordinator and clinician for these high-risk resource-intensive procedures.

Implementation of EMR-based standardized antibiotic desensitization protocols and its impact on providers

Background: As desensitization protocols become more readily available and published, more institutions are implementing them and searching for ways to streamline the process. There have been no published studies to date on the effect that electronic medical record systems (EMR) have on the safety and efficiency of β-lactam antibiotic desensitization. Objective: The purpose of this study was to evaluate the changes in workflow, efficiency, and medical errors after implementation of β-lactam antibiotic desensitization. Methods: A collaborative effort between the Allergy/Immunology Division and the Pharmacy Department led to the creation and implementation of antibiotic desensitization order sets. Pre- and postimplementation of β-lactam antibiotic surveys were sent to pharmacists and allergy/immunology fellows and attendings at a single-center tertiary care center. Results: There were only 26 valid respondents (12.3%) to both the pre- and postimplementation surveys. The percentage of respondents who thought that the time needed to prepare desensitization materials was < 4 hours increased from 23% to 77% (p < 0.001). The percentage of respondents who thought that the time needed to input electronic desensitization orders was < 1 hour increased from 19% to 54% (p = 0.002). The percentage of respondents who identified zero errors increased from 42% to 92% (p = 0.001). The perception of the overall desensitization process efficiency significantly increased (p < 0.001). Conclusion: Creation of standardized electronic β-lactam antibiotic desensitization order sets significantly decreased the time taken to order and prepare materials and increased overall efficiency.

COVID-19 pandemic: Practical considerations on the organization of an allergy clinic-An EAACI/ARIA Position Paper

BACKGROUND

The coronavirus disease 2019 (COVID-19) has evolved into a pandemic infectious disease transmitted by the severe acute respiratory syndrome coronavirus (SARS-CoV-2). Allergists and other healthcare providers (HCPs) in the field of allergies and associated airway diseases are on the front line, taking care of patients potentially infected with SARS-CoV-2. Hence, strategies and practices to minimize risks of infection for both HCPs and treated patients have to be developed and followed by allergy clinics.

METHOD

The scientific information on COVID-19 was analysed by a literature search in MEDLINE, PubMed, the National and International Guidelines from the European Academy of Allergy and Clinical Immunology (EAACI), the Cochrane Library, and the internet.

RESULTS

Based on the diagnostic and treatment standards developed by EAACI, on international information regarding COVID-19, on guidelines of the World Health Organization (WHO) and other international organizations, and on previous experience, a panel of experts including clinicians, psychologists, IT experts, and basic scientists along with EAACI and the "Allergic Rhinitis and its Impact on Asthma (ARIA)" initiative have developed recommendations for the optimal management of allergy clinics during the current COVID-19 pandemic. These recommendations are grouped into nine sections on different relevant aspects for the care of patients with allergies.

CONCLUSIONS

This international Position Paper provides recommendations on operational plans and procedures to maintain high standards in the daily clinical care of allergic patients while ensuring the necessary safety measures in the current COVID-19 pandemic.

Real-World Safety of CFTR Modulators in the Treatment of Cystic Fibrosis: A Systematic Review

Cystic fibrosis transmembrane conductance regulator (CFTR) modulator therapies target the underlying cause of cystic fibrosis (CF), and are generally well-tolerated; however, real-world studies indicate the frequency of discontinuation and adverse events (AEs) may be higher than what was observed in clinical trials. The objectives of this systematic review were to summarize real-world AEs reported for market-available CFTR modulators (i.e., ivacaftor (IVA), lumacaftor/ivacaftor (LUM/IVA), tezacaftor/ivacaftor (TEZ/IVA), and elexacaftor/tezacaftor/ivacaftor (ELX/TEZ/IVA)), and to identify ways in which the pharmacist on CF healthcare teams may contribute to mitigating and managing these AEs. The MEDLINE, EMBASE, CINAHL, and Web of Science Core Collection online databases were searched from 2012 to 1 Aug 2020. Full manuscripts or conference abstracts of observational studies, case series, and case reports were eligible for inclusion. The included full manuscripts and conference abstracts comprised of 54 observational studies, 5 case series, and 9 case reports. The types of AEs reported generally aligned with what have been observed in clinical trials. LUM/IVA was associated with a higher frequency of respiratory-related AE and discontinuation in real-world studies. A signal for mental health and neurocognitive AEs was identified with all 4 CFTR modulators. A systematic approach to monitoring for AEs in people with CF on CFTR modulators in the real-world setting is necessary to help better understand potential AEs, as well as patient characteristics that may be associated with higher risk of certain AEs. Pharmacists play a key role in the safe initiation and monitoring of people with CF on CFTR modulator therapies.

Mechanisms of Drug Desensitization: Not Only Mast Cells

Drug desensitization (DD) allows transient clinical tolerance to the drug in reactive patients and it is frequently and successfully used in the management of both IgE and non IgE-mediated hypersensitivity reactions (HRs). The underlying mechanisms behind this process is not well understood. The desensitization procedure is associated with the inhibition of mast cells degranulation and cytokine production, that, is attributable, at least partially, to the abrogation of Ca2+ mobilization; in vitro findings and in vivo mouse models of rapid desensitization show that the organization and spatial distribution of actin is critical for Ca2+ mobilization. Some clinical observations may suggest the induction of a longer memory of tolerance by DD and they raise the suspicion that other cells and mechanisms are involved in DD. Some data are emerging about the modifications of immune responses during DD in patients with previous immediate HRs. In particular, an increase of regulatory cytokines, mainly represented by IL-10, has been shown, and more importantly, the appearance of IL-35 producing T regulatory cells has been described during DD. The release of controlled cellular mediators by mast cells over time and the development of the antigen-specific regulation of adaptive response allow to safely and successfully reach the target dose of a first line drug during DD.

Diagnosis and management of the drug hypersensitivity reactions in Coronavirus disease 19: An EAACI Position Paper

Coronavirus disease 2019 (COVID-19), a respiratory tract infection caused by a novel human coronavirus, the severe acute respiratory syndrome coronavirus 2, leads to a wide spectrum of clinical manifestations ranging from asymptomatic cases to patients with mild and severe symptoms, with or without pneumonia. Given the huge influence caused by the overwhelming COVID-19 pandemic affecting over three million people worldwide, a wide spectrum of drugs is considered for the treatment in the concept of repurposing and off-label use. There is no knowledge about the diagnosis and clinical management of the drug hypersensitivity reactions that can potentially occur during the disease. This review brings together all the published information about the diagnosis and management of drug hypersensitivity reactions due to current and candidate off-label drugs and highlights relevant recommendations. Furthermore, it gathers all the dermatologic manifestations reported during the disease for guiding the clinicians to establish a better differential diagnosis of drug hypersensitivity reactions in the course of the disease.

Patients with high-grade alectinib-induced skin rash: How do we desensitize these patients? A case report and review of literature

With the advent of targeted therapy for non-small-cell lung cancer, there are many new available treatment options for patients whose cancer harbors an actionable mutation or alteration. These new medications come with numerous side effects, for some of which, the management is not well defined. Alectinib is a second-generation tyrosine kinase inhibitor approved for stage-IV lung adenocarcinoma with anaplastic lymphoma kinase gene rearrangement. Severe (⩾Grade 3) skin rash is a rare side effect of alectinib. Reintroducing alectinib in patients with severe skin rash is not well defined in the medical literature. While other case reports have outlined their approach and desensitization protocol, the maximum dose that patients were titrated up to in a desensitization protocol was 300 mg twice daily. Here, we report a case of Grade 3 skin rash secondary to alectinib, and our experience in managing the rash and reintroducing alectinib with a unique desensitization protocol to a max of 600 mg twice daily (full dose). This case could provide further guidance to oncologists managing patients with this adverse event and may aid in reducing concerns to both patients and physicians about recurrence of skin rash at the maximum dose.

Diagnostic procedures & practices in drug allergy/hypersensitivity: a survey of 13 Asian countries

BACKGROUND

The issues and challenges in the diagnosis of drug allergy/hypersensitivity among children and adults in Asia are likely to be different from non-Asian countries.

OBJECTIVE

To study the diagnostic modalities used in the evaluation and management of drug allergy/drug hypersensitivity reactions (DHRs) among member societies of the Asia Pacific Association of Allergy, Asthma and Clinical Immunology (APAAACI).

METHODS

A questionnaire comprising 41 questions was circulated electronically to member societies and individual members of APAAACI between January 23, 2020 and March 6, 2020.

RESULTS

Twenty-six respondents from 15 member societies and 1 individual member responded. European DHR guidelines were most commonly used. Skin prick and intradermal testing was used by 100%, with only 60% having access to commercial penicillin skin test reagents. In vitro-specific IgE tests were used by 75%, and basophil activation test by 56.3% for immediate DHR. Patch tests were used by 75% in contrast to lymphocyte transformation tests by 25% for nonimmediate DHR. Drug provocation tests were used by 68.8%, the most common indication being to exclude hypersensitivity where history/symptoms were not suggestive of drug hypersensitivity/allergy (93.3%). Human leukocyte antigen (HLA) genotype testing was mandatory among 25% respondents before new carbamazepine prescriptions, and 8.3% for allopurinol prescriptions.

CONCLUSIONS

There was increased use of skin testing for iodinated contrast media hypersensitivity and patch testing for nonimmediate DHR. HLA genotype testing prior to new carbamazepine, allopurinol and abacavir prescriptions remain variable despite strong associations for severe cutaneous adverse reactions with Asian ethnicity. Results of this survey form a useful framework for developing educational and training needs and for improving access to drug allergy diagnostic and treatment modalities across APAAACI member societies.

Successful Desensitization Protocol in an Infant Following Anaphylaxis Secondary to Recombinant Factor VIIa

Background: Recombinant factor VIIa (rFVIIa) is a highly purified recombinant protein. It is approved for the treatment and prevention of bleeding episodes associated with congenital factor VII deficiency, congenital hemophilia with inhibitors, and Glanzmann's thrombasthenia. The most commonly reported adverse events are thrombolytic in nature. In this report, we present a successful desensitization protocol administered to an infant with a history of anaphylaxis to rFVIIa. Case: A male infant with a history of gingival bleeding at the age of 6 months was diagnosed with factor VII deficiency with a factor VII level of 1%. His sister also had diagnosis of factor VII deficiency. Our patient was hospitalized at 10 months of age with generalized petechiae and bloody stools. Twenty minutes after administration of rFVIIa, he developed anaphylaxis that responded to epinephrine and supportive care. Subsequently he was evaluated at the allergy clinic, where a skin prick test with rFVIIa was negative. However, the intradermal skin test, applied with 1/1,000 (1 μg/1 mL, 0.1 mL) dilution of rFVIIa, showed induration of 8 mm (positive reaction). Because there is no alternative treatment for factor VII deficiency, we developed a successful 13-step desensitization protocol with rFVIIa (NovoSeven^®). Desensitization was performed an additional 2 times using the same protocol, one of which was for a head injury and the other for a swollen knee since the period between the doses was ∼3 months. Conclusion: Allergic reactions, such as anaphylaxis can occur without prior exposure. This can be due to the high molecular weight and structural property of the biological agent. In this report, we present an effective desensitization protocol for an infant with a history of anaphylaxis to rFVIIa. Desensitization protocols in this age group should be carried out in a medical facility and with specialized staff and equipment prepared to care for anaphylaxis.

Successful Desensitization Treatment with Osimertinib after the Development of Osimertinib-induced Urticaria in a Patient Undergoing Treatment for Non-small Cell Lung Cancer Harboring the EGFR T790M Mutation

Some patients discontinue receiving osimertinib for non-small cell lung cancer (NSCLC) harboring epidermal growth factor receptor (EGFR) Thr790Met (T790M) mutation due to adverse its effects. We report a case of successful desensitization therapy after osimertinib-induced urticaria. An 85-year-old Japanese woman received osimertinib as third-line therapy for NSCLC with the EGFR T790M mutation. After two days, she developed urticaria of the lower extremities. We started osimertinib desensitization therapy at 0.1 mg/day, which was gradually increased to 40 mg/day. She continued osimertinib for >12 months without adverse effects. Desensitization therapy with osimertinib could be useful for patients experiencing osimertinib-induced urticaria.

Guideline on diagnostic procedures for suspected hypersensitivity to beta-lactam antibiotics: Guideline of the German Society for Allergology and Clinical Immunology (DGAKI) in collaboration with the German Society of Allergology (AeDA), German Society for Pediatric Allergology and Environmental Medicine (GPA), the German Contact Dermatitis Research Group (DKG), the Austrian Society for Allergology and Immunology (ÖGAI), and the Paul-Ehrlich Society for Chemotherapy (PEG)

This guideline on diagnostic procedures for suspected beta-lactam antibiotic (BLA) hypersensitivity was written by the German and Austrian professional associations for allergology, and the Paul-Ehrlich Society for Chemotherapy in a consensus procedure according to the criteria of the German Association of Scientific Medical Societies. BLA such as penicillins and cephalosporins represent the drug group that most frequently triggers drug allergies. However, the frequency of reports of suspected allergy in patient histories clearly exceeds the number of confirmed cases. The large number of suspected BLA allergies has a significant impact on, e.g., the quality of treatment received by the individual patient and the costs to society as a whole. Allergies to BLA are based on different immunological mechanisms and often manifest as maculopapular exanthema, as well as anaphylaxis; and there are also a number of less frequent special clinical manifestations of drug allergic reactions. All BLA have a beta-lactam ring. BLA are categorized into different classes: penicillins, cephalosporins, carbapenems, monobactams, and beta-lactamase inhibitors with different chemical structures. Knowledge of possible cross-reactivity is of considerable clinical significance. Whereas allergy to the common beta-lactam ring occurs in only a small percentage of all BLA allergic patients, cross-reactivity due to side chain similarities, such as aminopenicillins and aminocephalosporins, and even methoxyimino cephalosporins, are more common. However, the overall picture is complex and its elucidation may require further research. Diagnostic procedures used in BLA allergy are usually made up of four components: patient history, laboratory diagnostics, skin testing (which is particularly important), and drug provocation testing. The diagnostic approach - even in cases where the need to administer a BLA is acute - is guided by patient history and risk - benefit ratio in the individual case. Here again, further studies are required to extend the present state of knowledge. Performing allergy testing for suspected BLA hypersensitivity is urgently recommended not only in the interests of providing the patient with good medical care, but also due to the immense impact of putative BLA allergies on society as a whole.

Desensitization to biological agents used in rheumatology

Biological agents such as monoclonal antibodies and fusion proteins are widely used for the treatment of patients with various rheumatic disorders, influencing the quality of life, disability and even mortality in patients. However, biological agents can evoke adverse reactions of different grades of severity. Although drug avoidance remains a gold standard in the care of patients hypersensitive to medication, in certain clinical situations the culprit drug is the drug of choice and cannot be replaced by another equally effective compound. In such cases, desensitization can allow the patient to be treated within current guidelines and with the most effective treatment. The authors searched Medline and Scopus databases for English-language sources using the following key words: hypersensitivity, desensitization, biologicals, adalimumab, etanercept, adalimumab, certolizumab, golimumab, rituximab, infliximab, ixekizumab, tocilizumab, anakinra and canakinumab. The aim of our review is to present the current knowledge about desensitization to biological agents and some guidelines according to patient inclusion, contraindications, procedures, and safety requirements. Drug desensitization is a new issue in rheumatology, and the solution to the problem of allergic reactions to biological drugs, which gives patients with rheumatic diseases the opportunity to extend and prolong their therapy. The present article is one of the first widely discussing this topic in the biological treatment of rheumatic diseases.