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

Update on the Management of Nonsteroidal Anti-Inflammatory Drug Hypersensitivity

The clinical phenotypes of nonsteroidal anti-inflammatory drug (NSAID) hypersensitivity are heterogeneous with various presentations including time of symptom onset, organ involvements, and underlying pathophysiology. Having a correct diagnosis can be challenging. Understanding their respective mechanisms as well as developing a comprehensive classification and diagnostic algorithm are pivotal for appropriate management strategy. Treatment modalities are based on the subtypes and severity of hypersensitivity reactions. Insights into the phenotypes and endotypes of hypersensitivity reactions enable personalized management in patients with suboptimal control of disease. This review updated the recent evidence of pathophysiology, classification, diagnostic algorithm, and management of NSAID hypersensitivity reactions.

Drug hypersensitivity reactions in Asia: regional issues and challenges

There are geographical, regional, and ethnic differences in the phenotypes and endotypes of patients with drug hypersensitivity reactions (DHRs) in different parts of the world. In Asia, aspects of drug hypersensitivity of regional importance include IgE-mediated allergies and T-cell-mediated reactions, including severe cutaneous adverse reactions (SCARs), to beta-lactam antibiotics, antituberculous drugs, nonsteroidal anti-inflammatory drugs (NSAIDs) and radiocontrast agents. Delabeling of low-risk penicillin allergy using direct oral provocation tests without skin tests have been found to be useful where the drug plausibility of the index reaction is low. Genetic risk associations of relevance to Asia include human leucocyte antigen (HLA)-B*1502 with carbamazepine SCAR, and HLA-B*5801 with allopurinol SCAR in some Asian ethnic groups. There remains a lack of safe and accurate diagnostic tests for antituberculous drug allergy, other than relatively high-risk desensitization regimes to first-line antituberculous therapy. NSAID hypersensitivity is common among both adults and children in Asia, with regional differences in phenotype especially among adults. Low dose aspirin desensitization is an important therapeutic modality in individuals with cross-reactive NSAID hypersensitivity and coronary artery disease following percutaneous coronary intervention. Skin testing allows patients with radiocontrast media hypersensitivity to confirm the suspected agent and test for alternatives, especially when contrasted scans are needed for future monitoring of disease relapse or progression, especially cancers.

A rapid desensitization protocol in a case of drotaverine-induced serum sickness-like reaction in a pregnant woman: A case report

Drotaverine is an antispasmodic drug used to treat gastrointestinal and genitourinary smooth muscle spasms. There are very few hypersensitivity reactions reported. Serum sickness-like disease is an immune-complex-mediated hypersensitivity reaction that presents with some typical features that include rash, fever and articular impairment sometimes associated with liver and renal dysfunctions, beginning 1-2 weeks after exposure to a culprit drug. Diagnosis is a clinical one, made usually on the basis of knowledge obtained by medical history and physical examination. Desensitization usually is recommended for type I reaction, but may be a solution for this type of immunological reaction when other therapeutic alternatives are ineffective or do not exist. We report the case of a 29-year-old pregnant female who developed serum sickness-like reaction after 5 days of daily drotaverine oral administration. The patient required antispasmodic treatment, with this drug, having a pregnancy with an imminent risk of abortion and the other therapeutic alternatives being ineffective. She underwent a rapid 7-step oral drotaverine desensitization protocol without recurrence of serum sickness-like reaction. To our knowledge, this is the first case report of desensitization to drotaverine, previously involved in a serum sickness-like reaction.

Protocols for drug allergy desensitization in children

Introduction: When a drug hypersensitivity reaction is proven, desensitization protocols allow the reintroduction of the molecule in patients for whom such therapy is essential. Through drug desensitization (DDS), a temporary immune tolerance is maintained for the single course of a specific therapy. In pediatrics, indications for such a procedure include children with chronic diseases, severe infectious diseases and/or malignancies, who have a proven drug hypersensitivity.Areas covered: We ran a search on PubMed and Web of Science for papers on DDS and on DDS in children. Most protocols and recommendations on DDS focus on adults and have been adapted for children. The best candidates for desensitization are children with a history of immediate, IgE-mediated drug allergy, but this therapy may be applied also in nonallergic hypersensitivities and in non-immediate reactions. Most protocols in literature focus on antibiotics, especially beta-lactams, on chemotherapeutic agents, and on monoclonal antibodies.Expert opinion: Pediatric allergists should cooperate with specialists in infectious diseases and onco-hematology to provide DDS to children in need. Standardized protocols and international guidelines are still needed to optimize such treatment and to implement it in clinical daily practice.

Loss of tolerance 5 days after discontinuing sulphonamide introduced via desensitization in delayed reaction

The fixed drug eruption is a non-immediate hypersensitivity reaction to drug, characterized by recurrent erythematous or violaceous, rounded, well-defined border plaques, which always appear in the same location every time the culprit drug is administered. The usual practice is to avoid the drug involved and to use a structurally different drug. However, there are situations in which there is no safe and effective therapy. In such situations, desensitization is the only option. We describe the case of a patient who presented fixed eruption due to sulfamethoxazole-trimethoprim, who underwent successful desensitization, but required a repeat procedure twice due to relapse after inadvertent full-dose reintroduction. In non-immediate hypersensitivity reaction to drug, the indication is controversial and there is no technical standardization. Furthermore, the time at which such tolerance is lost after discontinuing the drug involved is unknown. In severe non-immediate reactions of types II and III, desensitization is contraindicated. The patient underwent desensitisation to sulfamethoxazole-trimethoprim three times − the first with recurrence of lesions and the second and third without manifestations, all concluded successfully and with no premedication.

Successful Desensitization with Crizotinib after Crizotinib-induced Liver Injury in ROS1-rearranged Lung Adenocarcinoma

Crizotinib has been approved for patients with advanced lung adenocarcinoma harboring rearrangements of the c-ROS-1 (ROS1) and anaplastic lymphoma kinase (ALK) genes. We report a patient with ROS1-rearranged lung adenocarcinoma who developed a crizotinib-induced mixed/cholestatic type of liver injury. The patient discontinued crizotinib after 34 days due to liver toxicity. Twenty-four days later, when transaminases and C reactive protein (CRP) were normalized, crizotinib was resumed using an oral desensitization method. The patient was successfully treated for manageable recurrence of liver injury and has been able to continue the treatment.

Antimicrobial Desensitization: A Review of Published Protocols

Antimicrobial desensitization represents a last-line option for patients with no alternative therapies, where the benefits of this intensive process must outweigh the potential harm from drug exposure. The goal of antimicrobial desensitization procedures is to establish a temporary state of tolerance to drugs that may otherwise cause hypersensitivity reactions. While no universal antimicrobial desensitization protocols exist, this review critically analyzes previously published desensitization protocols. The purpose of this review is to provide a greater insight for clinicians and institutions to ensure desensitization procedures are efficacious while minimizing potential for patient harm. With an increasing rate of antimicrobial resistance and the critical need to preserve antimicrobial agents, desensitization may represent another option in our antimicrobial stewardship toolkit.

A practical 16-day desensitization protocol in lenalidomide-induced non-immediate hypersensitivity reactions

BACKGROUND

Desensitization in immediate-type hypersensitivity reactions (HRs) caused by chemotherapeutics is well described and standardized for many drugs. However, there are no standardized protocols in non-immediate HRs.

OBJECTIVE

To evaluate the effectiveness of a 16-day desensitization protocol in the non-immediate HRs induced by lenalidomide.

METHODS

According to our previously published slow desensitization protocol, we desensitized patients who had experienced non-immediate HRs attributable to lenalidomide. The protocol was started with the 1/100 of the daily-prescribed dose in milligrams of the culprit drug; then the doses were slowly increased to complete the procedure in 16 days. Demographic and clinical features of the patients were further appraised.

RESULTS

Ten patients (mean age was 64.7 ± 10.8 years; 7 male) were successfully desensitized to lenalidomide. The mean reaction time was 7.3 ± 3.9 days in the history, and the reaction types were delayed urticaria (n = 4), eczematous rash (n = 3), and maculopapular eruptions (n = 3). The desensitization was successfully completed in 16 days in 9 patients. In 1 patient, maculopapular eruptions developed on the 11th day, and the patient was treated with corticosteroids. We repeated the previous tolerated dose longer and completed with a slower dose increasement, and the targeted dose was achieved in 35 days.

CONCLUSION

The 16-day desensitization protocol seemed to be safe and effective in the non-immediate type drug HRs caused by lenalidomide.

Drug hypersensitivity in HIV infection

PURPOSE OF REVIEW

Immune-mediated adverse drug reactions (IM-ADRs) are many times more common in HIV-infected patients. Usual offending drugs include antiretroviral and antiinfectives, but the burden of specific drug IM-ADRs is population-specific; changing as new and fixed dose combinations enter the market, and drug-resistance patterns demand. This review considers recent literature on epidemiology, mechanisms, clinical management and prevention of IM-ADRs amongst persons living with HIV/AIDS.

RECENT FINDINGS

Epidemiological studies continue to describe high rates of delayed hypersensitivity to known offenders, as well as similar reactions in preexposure prophylaxis. IM-ADRs to oral and injectable integrase strand transfer inhibitors are reported with expanding use. The clinical spectrum and management of IM-ADRs occurring in HIV-infected populations is similar to uninfected; with exceptions such as a recently described severe delayed efavirenz DILI with high mortality. Furthermore, the context can be unique, such as the lower than expected mortality in a Stevens-Johnson syndrome and toxic epidermal necrolysis (SJS/TEN) cohort from a HIV/TB high burden setting. Programmatic data showing the near complete elimination of Abacavir drug hypersensitivity syndrome following implementation of HLA-B57:01 screening is a stellar example of how prevention is possible with mechanistic insight.

SUMMARY

IM-ADRs remain a challenge in persons living with HIV. The complexities posed by polypharmacy, overlapping drug toxicities, drug interactions, overlap of IM-ADRs with other diseases, limited alternative drugs, and vulnerable patients with advanced immunosuppression with high mortality, necessitate increased use of drug provocation testing, treat-through and desensitization strategies. There is an urgent need for improved diagnostics and predictive biomarkers for prevention, or to guide treat-through, rechallenge and desensitization approaches.

Rashes and other hypersensitivity reactions associated with antiepileptic drugs: A review of current literature

This article provides an overview of the pathogenesis and risk factors associated with antiepileptic drug (AED) hypersensitivity reactions, provides prescribing guidelines that may minimize the risk of antiepileptic induced rashes, and discusses treatment options for rashes. Articles indexed in PubMed, Science Citation, and Google Scholar (January 1946-March 2019) were systematic searched using the following key terms: hypersensitivity, rash, antiepileptic, epilepsy, cross-sensitivity, desensitization, patch testing and supplemented with our clinical experiences. Additional references were identified from a review of literature citations. AEDs are associated with cutaneous adverse reactions. Aromatic AEDs and higher titration rates are associated with increased risk of hypersensitivity reaction. Patient characteristics, underlying health conditions, and genetic variations may increase the likelihood of a hypersensitivity reaction. Once a hypersensitivity reaction occurs, the likelihood of cross sensitivity to another AED increases, especially among other aromatic AEDs. Withdrawal of the causal agent and initiation of a lower risk agent usually leads to resolution of symptoms. Desensitization protocols may be an option for patients whose seizures only respond to the AED causing the rash.

Successful cholecalciferol desensitisation in a case of delayed hypersensitivity

Hypersensitivity to cholecalciferol (vitamin D₃) or its active metabolite, calcitriol, is an exceedingly rare clinical phenomenon, with only 2 previously reported cases of suspected immediate hypersensitivity. Diagnosis of delayed drug hypersensitivity reactions is inherently difficult due to the lack of any robust in vitro diagnostic assay, particularly in those patients for whom provocation testing confers an unacceptable risk. In these situations, diagnosis relies on reproducible clinical manifestations following administration of the culprit agent, resolution upon its withdrawal and exclusion of other potential differential diagnoses. Based on these criteria, we propose the first reported case of delayed hypersensitivity to cholecalciferol successfully managed with a desensitisation protocol to pure cholecalciferol.

Recent developments in drug hypersensitivity in children

Introduction: Drug allergy is an important public health problem that causes 0.4-10.3% of hospital admissions in children. The epidemiology, clinical spectrum, diagnosis, and management of drug hypersensitivity reactions (DHRs) differ in pediatric and adult patients. However, the same algorithms used in adults have often been applied in the pediatric population due to a lack of evidence in the literature. Areas covered: In this review, we aimed to discuss recent developments in the area of pediatric DHRs based on the growing body of literature advancing our understanding of the epidemiology, clinical aspects, and diagnostic approaches to DHRs in children. Expert opinion: Misdiagnosis, under-diagnosis, and self-diagnosis are common problems related to drug allergies in children. Viral infections are particularly frequent in children and make diagnosis difficult. Identifying true DHR is a key step in the management of drug allergy in children. Therefore, a complete allergy work-up with standardized drug allergy tests is necessary. In order to eliminate non-standardized tests, future studies including larger numbers of children should be conducted to determine more accurate standardized tests for diagnosing DHRs in the pediatric population.

Hypersensitivity to monoclonal antibodies used for cancer and inflammatory or connective tissue diseases

OBJECTIVE

To review the medical literature on hypersensitivity reactions to therapeutic monoclonal antibodies for patients with malignant tumors and chronic inflammatory or connective tissues diseases.

DATA SOURCES

We searched the PubMed database using the terms monoclonal antibody, hypersensitivity, and allergy.

STUDY SELECTIONS

We selected case reports and cohort studies of patients with hypersensitivity reactions to monoclonal antibodies. We included selected review articles to glean expert opinion on issues for which high-quality data are available. We sought specific information on the incidence, clinical description, pathobiology, and treatment of reactions.

RESULTS

Hypersensitivity reactions to therapeutic monoclonal antibodies can be classic type I (mast cell mediated, perhaps IgE dependent) reactions, cytokine release reactions, or type IV cell-mediated reactions. There are limited data on the frequency of such reactions, and because new agents are added to the set at a relatively high rate, it is difficult to determine precisely the incidence of reactions to this class of drugs as a whole. The classification of a specific hypersensitivity reaction depends mainly on the medical history. Skin testing may be available but often is not validated and may be prohibitively expensive. Avoidance of the culpable agent is ideal, but if treatment with the responsible drug is necessary, rapid drug desensitization is an option for type I reactions. Desensitization is less likely to be effective for cytokine release reactions and is contraindicated for type IV reactions.

CONCLUSION

Hypersensitivity reactions to therapeutic monoclonal antibodies are heterogeneous. Management depends on accurate identification and thoughtful consideration of the pathobiologic features of the reaction.

Management of adverse reactions to first-line tuberculosis antibiotics

PURPOSE OF REVIEW

Tuberculosis (TB) is the commonest infectious cause of death globally. Adverse reactions to first-line tuberculosis antibiotics are common and have a major impact on the outcomes of patients as second-line antibiotics are less effective and more toxic. The present review addresses the most recent literature regarding epidemiology, investigating reactions, and reintroducing treatment in patients who have had their treatment interrupted.

RECENT FINDINGS

Studies have demonstrated that up to 60% of patients experience adverse reactions to TB treatment; around a third of these are idiosyncratic and may relate to immune sensitization. There is an increased risk in patients with HIV. For patients with severe cutaneous reactions patch testing has an important role; however, systemic reactions to patch testing are common in patients with HIV. In-vitro testing remains limited to specialist centers but studies have identified drug-specific lymphocyte responses in patients with cutaneous and liver reactions. Desensitization of patients with severe cutaneous reactions have been demonstrated to be possible, albeit at high risk.

SUMMARY

Management of these patients remains suboptimal. Better identification of predisposing factors, such as HLA alleles, are needed to identify patients at risk. Improved in-vitro diagnostics will reduce the need to re-expose the patient to the drug and optimized desensitization regimens will improve patient safety when drugs have to be re-introduced.

Desensitization in patients with hypersensitivity to haem arginate: A case report

Background

Porphyria comprises a group of metabolic disorders caused by the irregular activities of enzymes within the haem biosynthetic pathway. This disease can provoke a large variety of symptoms. Acute porphyria attacks need to be treated urgently to avoid prolonged illness and fatal complications. Haem arginate, a concentrated haem solution stabilized with arginine, is the only preparation available for treatment in Europe and South America. This report describes a safe desensitization protocol for patients who require such treatment and have haem arginate hypersensitivity.

Case presentation

A 25-year-old female patient diagnosed with acute intermittent porphyria, who had an anaphylactic reaction while receiving haem arginate. The patient was treated with a desensitization protocol for patients with hypersensitivity to haem arginate.

Conclusion

Porphyria is a disease that can significantly compromise a patient's quality of life. The desensitization protocol for patients with hypersensitivity to haem arginate is a safe and effective treatment option for patients with a history of haem arginate allergies, to whom it is not possible to administer haematin.

Rapid subcutaneous desensitization for the management of delayed hypersensitivity reactions to omalizumab：A case report

WHAT IS KNOWN AND OBJECTIVE

Omalizumab is effective as an add-on drug to treat severe persistent allergic asthma. However, delayed hypersensitivity reactions to omalizumab may deprive patients of its use. Rapid subcutaneous desensitization could be a solution.

CASE DESCRIPTION

A 61-year-old man developed a delayed allergy to omalizumab after the first injection. A 14-step desensitization procedure was applied to the patient and was successful.

WHAT IS NEW AND CONCLUSION

Delayed hypersensitivity reactions to omalizumab are rare, but they may cause the interruption of drug usage. Desensitization to omalizumab could be a possible solution.

Pediatric Drug Hypersensitivity

PURPOSE OF REVIEW

Pediatric drug hypersensitivity is a rapidly evolving field. The purpose of this paper is to review the current state of pediatric drug hypersensitivity and highlight new developments in diagnosis and management.

RECENT FINDINGS

This paper will discuss the safety and use of risk stratification to proceed directly to oral challenge without prior skin testing for β-lactam reactions. We review unique aspects of pediatric drug challenges and desensitizations. It is important to accurately diagnose pediatric drug hypersensitivity reactions through a detailed history, physical examination, and available diagnostic testing. Understanding of the underlying mechanism leads to appropriate classification which is necessary to direct management. The decision to perform drug challenge, desensitization, or recommend avoidance of a medication can have a significant impact on a patient's treatment. Utilization of weight-based dose and infusion rate adjustments for current drug challenge and desensitization protocols optimize success.

Drug desensitization in allergic children

Drug allergy is an increasing problem worldwide, affecting all populations and races, children and adults, and for which diagnosis and treatment are not well standardized yet. Besides classical treatments, new drugs have been developed, especially for patients suffering from malignancies and chronic inflammatory diseases, that specifically target the cause of the disease. For those patients requiring such molecules, it is sometimes difficult to find an alternative drug when hypersensitivity reactions occur. Desensitization is therefore the best option whenever no alternative therapy is available but also when alternative treatments are considered therapeutically inferior and or more toxic. Despite its clinical success, little is known about the mechanisms and molecular targets of drug desensitization. Desensitization protocols use a gradual dose escalation to allow the safe administration of a treatment to which a patient previously presented a hypersensitivity reaction. The procedure requires special training and coordination of an allergy team, including physicians, nurses, and pharmacists, working together to safely and successfully implement desensitization protocols when appropriate. There is no difference in desensitization protocol between adults and children, except for the final cumulative dose of the administered drug.

Interleukin-10 is increased in successful drug desensitization regardless of the hypersensitivity reaction type

Background

Little is known about the mechanism of desensitization in hypersensitivity drug reactions.

Objective

The aim of this study was to evaluate the effects of drug desensitization on some cytokine levels in patients desensitized for drug hypersensitivity reactions.

Methods

Patients with a hypersensitivity reaction to any drug for whom desensitization was planned with the culprit drug, patients who could tolerate the same drugs and healthy subjects who were not exposed to these drugs were enrolled. Bead-based Milliplex MAP multiplex technology was used to determine interleukin (IL)-4, IL-5, interferon-γ and IL-10 levels in the sera of the subjects as a baseline and 24 hours after desensitization had been completed in the patients.

Results

A total of 26 patients (16 female [61.5%]; mean age 48.46 ± 15.97 years old), 10 control patients (5 female [50%]; mean age 47.4 ± 15.4 years old) and 5 healthy subjects (3 female [60%]; mean age 34.2 ± 5.6 years old) were enrolled. Four of the 26 patients did not tolerate the procedure and were grouped as the 'unsuccessful desensitization group' whereas 22 patients successfully completed the procedure and formed the 'successful desensitization group.' Baseline cytokine levels in the 3 groups were not statistically different. Postdesensitization IL-10 levels in the successful desensitization group were significantly higher than their initial levels (p = 0.005) whereas none of the cytokine levels significantly changed in the unsuccessful desensitization group. The rise in IL-10 levels was greater in chemotherapeutic desensitizations when compared to other drugs (p = 0.006).

Conclusion

Successful desensitization independent of the hypersensitivity reaction type seems to be related to the increase of IL-10.

Efficacy and tolerability of desensitization in the treatment of delayed drug hypersensitivities to anti-tuberculosis medications

BACKGROUND

Delayed drug hypersensitivity to first-line anti-tuberculosis medication is a major challenge in tuberculosis treatment.

OBJECTIVE

This study was performed to investigate the efficacy/tolerability of desensitization therapy in treatment of first-line anti-tuberculosis medication hypersensitivity and the usefulness of immunologic evaluation therein.

METHODS

This study was conducted as a prospective, observational cohort study. Subjects who experienced hypersensitivity reactions, including maculopapular exanthema (MPE) and drug reaction with eosinophilia and systemic symptoms (DRESS), to first-line anti-tuberculosis medications (isoniazid [INH], ethambutol [EMB], rifampin [RFP], and pyrazinamide [PZA]) were enrolled. Patch, intradermal, lymphocyte transformation, and oral provocation tests were performed to determine culprit drugs, which were desensitized with rapid and graded challenge protocols. Breakthrough reactions (BTRs) during or after desensitization were assessed.

RESULTS

In total, 31 desensitization treatments (INH, 8; EMB, 8; RFP, 11; PZA, 4) to 12 patients (8 with MPE and 4 with DRESS) were performed. The overall success rate of desensitization was 80.7%. All the study subjects except one completed the full course of anti-tuberculosis treatment. The overall BTR free rate was 64.5%. Sixteen (80%) treatments for MPE and four (36.4%) for DRESS were BTR free (P = 0.023). Drugs that were positive on any two of three immunologic studies showed significantly high BTR rates (P = 0.014), although this was not correlated with desensitization failure rate.

CONCLUSION

Rapid desensitization therapy to multiple anti-tuberculosis medications for delayed drug hypersensitivity was safe and successful. Combination of multiple immunologic evaluations may predict BTR although it needs validation in larger studies.

Successful rapid oral desensitization for dual hypersensitivity to isoniazid and rifampin while treating central nervous system tuberculosis

Tuberculosis of the central nervous system (CNS-TB) is a critical disease with poor prognosis if not diagnosed and treated early. A regimen of drugs with good CNS penetration is required for treatment. Treatment options are limited in case of hypersensitivity reaction of the recommended regimen. We are reporting a rare instance where a patient developed hypersensitivity to both first line agents (isoniazid and rifampin) for CNS-TB and was successfully desensitized against both these medications to complete the treatment course using the rapid desensitization process. There have been reported cases of desensitization to anti tuberculous medications in cases with pulmonary tuberculosis and hypersensitivity reaction. In this review article we discuss the prior used methods of slow and rapid desensitization in case on non-CNS tuberculosis infections. This is the first reported case to use similar method of rapid desensitization in treatment of central nervous system infection.

Comparing Allergist and Cardiologist Considerations for the Optimal Management of Thienopyridines Hypersensitivity

BACKGROUND AND OBJECTIVE

The thienopyridine family includes ticlopidine, clopidogrel and prasugrel which are antiplatelet drugs largely used, mainly associated to aspirin, for treatment of acute coronary syndromes and after percutaneous coronary interventions, to avoid thrombosis. In some patients, thienpyridines may cause hypersensitivity reactions which jeopardize the optimal therapeutic and preventive approach to vascular diseases. The management of thienopyridine hypersensitivity seems to be best done as an interdisciplinary collaboration between the allergist and cardiologist.

METHOD

The present study investigates the management of thienopyridines hypersensitivity on the basis of published case reports and studies, comparing the pro and contro of pharmacological treatments, different desensitization protocols to thienopyridines and substitution of antiplatelet agents eaches others, according to the point of view of cardiologist and allergist. For the cardiologist, the important issues are the necessity of continuing therapy, the desired duration of therapy based on the clinical indication of the individual patient and appropriateness of using one of the alternative P2Y12 inhibitors. For the allergist, the important issues are weighing the risk and benefits of the various therapeutic options: treating "through" desensitization, or switching to an alternative agent.

RESULTS AND CONCLUSION

All the data seem to suggest that only working together, a cardio-allergy team of specialists may evaluate and offer the best approach to clinical decision-making for the individual patient.

Tolerance Induction to Antituberculosis Drugs in a Patient With Stevens-Johnson Syndrome/Toxic Epidermal Necrolysis Overlap

Tolerance induction and desensitization in Stevens-Johnson syndrome (SJS) or in toxic epidermal necrolysis (TEN) have been described as an absolute contraindication by some authors, but there are cases where there is no treatment alternative. Tuberculosis (TB) remains a leading cause of morbidity and mortality in developing countries and ranks alongside HIV as a leading cause of death worldwide. Severe drug reactions, such as SJS and TEN, occurring in these individuals are lifethreatening. Since alternative therapies for TB are limited, the role of desensitization and reintroduction becomes essential. We describe a case of tolerance induction to anti-TB drugs in a patient with SJS/TEN overlap syndrome using a specifically designed premedication, comedication, and desensitization protocol.

Sulfonamide Drug Allergy

PURPOSE OF REVIEW

We sought to review past and current literature on sulfonamide drug allergy and distill it in a practical manner to assist the clinician, specifically focusing on cross-reactivity and desensitization.

RECENT FINDINGS

There do not appear to be consistent genetic markers to reliably predict features of or the presence hypersensitivity reactions. Recent evidence continues to alleviate early concerns cross-reactivity between sulfonamide antibiotics and non-antibiotics. Sulfonamide drug allergy is frequently encountered by the practicing clinician. For sulfonamide antibiotics, delayed rash is the most common clinical manifestation. There is no current evidence to support avoidance of all non-antibiotic sulfonamides in those with a reported allergy to sulfonamide antibiotics, although certain scenarios require caution. Available evidence supports the cautious reintroduction of sulfonamide antibiotics via desensitization, which is usually well tolerated and should be considered in those with strong indications for trimethoprim-sulfamethoxazole and a reported sulfonamide allergy.

Antibiotic Allergy in Pediatrics

The overlabeling of pediatric antibiotic allergy represents a huge burden in society. Given that up to 10% of the US population is labeled as penicillin allergic, it can be estimated that at least 5 million children in this country are labeled with penicillin allergy. We now understand that most of the cutaneous symptoms that are interpreted as drug allergy are likely viral induced or due to a drug-virus interaction, and they usually do not represent a long-lasting, drug-specific, adaptive immune response to the antibiotic that a child received. Because most antibiotic allergy labels acquired in childhood are carried into adulthood, the overlabeling of antibiotic allergy is a liability that leads to unnecessary long-term health care risks, costs, and antibiotic resistance. Fortunately, awareness of this growing burden is increasing and leading to more emphasis on antibiotic allergy delabeling strategies in the adult population. There is growing literature that is used to support the safe and efficacious use of tools such as skin testing and drug challenge to evaluate and manage children with antibiotic allergy labels. In addition, there is an increasing understanding of antibiotic reactivity within classes and side-chain reactions. In summary, a better overall understanding of the current tools available for the diagnosis and management of adverse drug reactions is likely to change how pediatric primary care providers evaluate and treat patients with such diagnoses and prevent the unnecessary avoidance of antibiotics, particularly penicillins.

A novel outpatient desensitization protocol for recombinant human erythropoietin allergy in a pediatric patient

Background

Recombinant human erythropoietin, such as epoetin alfa and darbepoetin alfa, is an important therapy for anemia due to chronic renal failure. Allergy to recombinant human erythropoietin and the need for desensitization are rare.

Case presentation

We report here a novel epoetin alfa outpatient desensitization protocol in a girl who developed delayed cutaneous hypersensitivity to subcutaneous epoetin alfa and intravenous darbepoetin alfa. An initial attempt at traditional epoetin alfa desensitization failed, so we created a slower 17-day outpatient desensitization that succeeded and allowed treatment continuation.

Conclusions

This case highlights the notion that delayed-type hypersensitivity to recombinant human erythropoietin can occur as evident by reproducible reactions after repeated exposures and slow outpatient desensitization can be considered when a trial of more rapid induction of tolerance is unsuccessful.

Successful drug desensitization in patients with delayed-type allergic reactions to anti-tuberculosis drugs

OBJECTIVE

To evaluate the outcomes of anti-tuberculosis drug desensitization.

METHODS

This was a retrospective study. Inclusion criteria were as follows: age >18years, documented tuberculosis infection, a previous cutaneous allergic reaction to anti-tuberculosis drugs, and having undergone drug desensitization between January 2003 and March 2014. The definition of allergic reaction to anti-tuberculosis drugs included (1) a temporal relationship between drug use and the allergic reaction; (2) improvement in the allergic reaction after drug withdrawal; (3) recurrence of the allergic reaction after reintroduction of only the offending drug; and (4) absence of other causes.

RESULTS

A total of 19 desensitization procedures were performed. The drugs used for these procedures were isoniazid (n=7), rifampicin (n=6), or ethambutol (n=6). Of note, severe allergic reactions (Stevens-Johnson syndrome (n=4), erythema multiforme (n=3), and drug rash with eosinophilia and systemic syndrome (n=1)) were included. All patients underwent resolution of the previous allergic reactions before desensitization. The median duration of desensitization was 18 days. The success rate was 78.9%. The allergic reactions following failed desensitization were not severe; most were maculopapular rashes.

CONCLUSIONS

The desensitization protocol for anti-tuberculosis drugs was associated with a high success rate, and the individuals who failed desensitization experienced mild allergic reactions.

Delayed-type hypersensitivity to oral and parenteral drugs

Adverse drug reactions of the delayed type rank among the most common dermatoses and are predominantly characterized by exanthematous macular or maculopapular eruptions. However, approximately 2 % of affected individuals develop severe or even life-threatening systemic immune reactions associated with organ involvement, requiring immediate diagnosis and treatment. Numerous drugs are capable of eliciting delayed-type hypersensitivity reactions, with antibiotics, anticonvulsant drugs, and the xanthine oxidase inhibitor allopurinol being the most common. Apart from genetic susceptibility, predisposing factors for the development of drug hypersensitivity reactions include high drug doses, polypharmacy, long treatment duration, female gender, as well as acute or chronic infections.

Delayed Cutaneous Hypersensitivity Reactions to Antibiotics: Management with Desensitization

Successful desensitization to mild to moderate delayed cutaneous adverse reaction to antibiotics has been described in a limited number of antibiotics and found to be safe. However, there are ample opportunities to standardize protocols for delayed cutaneous adverse reactions to antibiotics.