Antibiotic desensitization for the allergic patient: 5 years of experience and practice

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 tetracyclines: Skin testing, graded challenge, and desensitization regimens

BACKGROUND

Hypersensitivity reactions (HSRs) to tetracyclines and the related compound, tigecycline, can limit the use of these medications and compromise optimal patient care. Despite this, there is little discussion in the literature describing the presentation of these reactions or guiding clinicians on the management of these reactions in adult and pediatric patients.

OBJECTIVE

To describe the clinical features, optimal diagnostic approach, and management of HSRs to tetracyclines.

METHODS

Patients with reactions to tetracyclines at our institution from 2011 to 2019 were identified by retrospective chart review. Skin testing protocols were designed for each antibiotic. Graded challenge and desensitization procedures were devised based on medical history, skin testing results when available, and need for readministration.

RESULTS

The HSRs to tetracyclines, their workup, and management are described for 10 patients, aged 7 to 68 years. Our skin testing protocols for doxycycline, minocycline, and tigecycline described herein had good negative predictive value. When skin testing was negative and the initial reaction was not severe, graded challenge to the culprit drug was performed. Using the included procedures, 3 patients were desensitized to oral doxycycline, 3 to oral minocycline, and 2 to intravenous tigecycline. All the desensitizations were successful.

CONCLUSION

Once identified, HSRs to tetracyclines can be further evaluated with skin testing and graded challenge and managed in appropriate cases with desensitization. These procedures can facilitate first-line therapy for patients who require tetracyclines but developed hypersensitivity reactions.

Heparin challenge test in patients undergoing cardiac surgery: dealing with heparin allergy

: A history of heparin hypersensitivity in patients undergoing cardiopulmonary bypass surgery poses the dilemma of which anticoagulant to use. Here, we report the successful use of a heparin challenge test in a 66-year-old female candidate for coronary artery bypass graft surgery with a past medical history of enoxaparin type I hypersensitivity after pulmonary embolism. Challenge and desensitization protocols are effectively used for essential antibiotics in patients with severe infections and/or allergies, or patients with aspirin intolerance requiring revascularization for coronary disease. A successful use of desensitization protocols to unfractionated heparin has been previously described in four patients undergoing cardiac surgery with various schemes. However, our case report indicates that a challenge test may also offer a quick, safe and effective approach in patients with a history of hypersensitivity reactions to heparin with inconclusive diagnostic tests and/or whenever the use of alternative heparins is tricky.

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.

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.

Evaluation of Pharmacy-Developed Antibiotic Desensitization Protocols

BACKGROUND

Parameters within reconstitution, storage, stability, and administration may be optimized according to the unique pharmacokinetics of each antibiotic to ensure a successful desensitization.

OBJECTIVE

The study aims to evaluate the successfulness and safety of antibiotic desensitization protocols developed by the pharmacy department at our institution.

METHODS

A retrospective study was conducted at an 800-bed, urban, tertiary care, academic medical center. A total of 36 patients 18 years of age or older, admitted to our intensive care units between March 2013 and July 2017, who underwent antibiotic desensitization utilizing our pharmacy developed protocols were included.

RESULTS

In 36 patients, 61 desensitization cases were identified and included; 17 (47%) were male, 27 (75%) were Caucasian, and the median age was 55 years (range 19-94). In all, 15 different antibiotics were administered for desensitization, with meropenem (n = 12, 20%), ampicillin (n = 7, 11%), piperacillin/tazobactam (n = 7, 11%), and penicillin (n = 7, 11%) being the most common; 59 (97%) of 61 desensitizations were completed successfully with or without experiencing reactions, and 53 (89%) of the successful desensitization cases were completed without reactions. Two cases were categorized as anaphylaxis, which was severe enough to terminate the desensitization process. Of the 59 cases successfully completed, the 6 (10%) cases that experienced reactions were managed successfully during desensitization with completion of the process. Conclusion and Relevance: The findings suggest that our pharmacy-developed antibiotic desensitization protocols are successful and safe and may be adapted by other institutions.

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.

Management of Children with Hypersensitivity to Antibiotics and Monoclonal Antibodies

Proper management of drug allergy in children is based on a thorough history, in vitro testing (if available), in vivo testing, and drug challenge. This approach has been well developed with beta-lactam drugs but not with non-beta-lactam drugs and monoclonal antibodies. Children commonly develop rashes during an antibiotic course, which can lead to misdiagnosis of drug allergy. Clinical reactions to monoclonal antibodies vary and are managed depending on the type. A better knowledge of drug reactions that can occur in antibiotic allergy and monoclonal allergy can aid a provider in better management of their drug-allergic pediatric patients.

Desensitization to Oxcarbazepine: Long-Term Efficacy and Tolerability

BACKGROUND AND PURPOSE

Antiepileptic drug (AED)-associated cutaneous adverse drug reactions can lead to the discontinuation of medications. The aim of this study was to determine the long-term efficacy and safety of performing desensitization to oxcarbazepine.

METHODS

This study involved 20 patients who exhibited cutaneous adverse drug reactions associated with oxcarbazepine use between July 2009 and March 2016 at Samsung Medical Center. All of the participants had to discontinue oxcarbazepine despite presenting initially positive responses. Human leukocyte antigen genotyping was performed to detect the genetic predisposition to Stevens-Johnson syndrome. The desensitization to oxcarbazepine was performed with a starting dosage of 0.1 mg/day. Efficacy was evaluated by comparing the frequency of seizures before and at 1 and 3 years after desensitization. Adverse events occurring during desensitization and the retention rate after desensitization were also investigated.

RESULTS

Nineteen patients (95%) safely completed the desensitization protocol. One withdrew owing to emotional problems that appeared to be associated with oxcarbazepine. The follow-up period was 4.6±1.2 years (mean±SD), and oxcarbazepine was maintained for more than 3 years after desensitization in 15 patients (83.3%). The response rates were 84.2% and 77.8% at 1 and 3 years after desensitization, respectively. Eight patients remained seizure-free for 3 years, and two discontinued all AEDs. Transient adverse reactions such as mild rash and itching were reported by five patients during desensitization.

CONCLUSIONS

This study has demonstrated the long-term efficacy and safety of desensitization to oxcarbazepine in patients exhibiting cutaneous adverse drug reactions. This favorable outcome should encourage the implementation of desensitization in patients presenting with hypersensitivity to oxcarbazepine as an alternative strategy in clinical practice.

Immediate-type hypersensitivity drug reactions

Hypersensitivity reactions including anaphylaxis have been reported for nearly all classes of therapeutic reagents and these reactions can occur within minutes to hours of exposure. These reactions are unpredictable, not directly related to dose or the pharmacological action of the drug and have a relatively high mortality risk. This review will focus on the clinical presentation, immune mechanisms, diagnosis and prevention of the most serious form of immediate onset drug hypersensitivity reaction, anaphylaxis. The incidence of drug-induced anaphylaxis deaths appears to be increasing and our understanding of the multiple and complex reasons for the unpredictable nature of anaphylaxis to drugs is also expanding. This review highlights the importance of enhancing our understanding of the biology of the patient (i.e. immune response, genetics) as well as the pharmacology and chemistry of the drug when investigating, diagnosing and treating drug hypersensitivity. Misdiagnosis of drug hypersensitivity leads to substantial patient risk and cost. Although oral provocation is often considered the gold standard of diagnosis, it can pose a potential risk to the patient. There is an urgent need to improve and standardize diagnostic testing and desensitization protocols as other diagnostic tests currently available for assessment of immediate drug allergy are not highly predictive.

A successful desensitization protocol for horse-derived antithymocyte globulin in severe aplastic anemia

BACKGROUND

Horse antithymocyte globulin (h-ATG) (ATGAM(®) ) is the first choice of treatment in very severe patients with aplastic anemia who do not have any HLA matched sibling donor. h-ATG is a heterologous serum that may cause anaphylaxis. Alternative treatment strategies must be planned in case of hypersensitivity. Desensitization must be considered in patients without an alternative treatment of choice. We aimed to present the h-ATG desensitization protocol and consider its effectiveness in patients with aplastic anemia who are hypersensitized with h-ATG and do not have an alternative treatment of choice.

METHODS

Skin prick tests were performed with non-diluted solution in eight very severe patients with aplastic anemia who are followed up in Ege University Children's Hospital. Although skin prick test was found negative in these eight patients, different dilution h-ATG intradermal tests were performed and found positive in all patients. h-ATG desensitization program was started to these hypersensitized patients.

RESULTS

Desensitization program was started to six male and two female very severe patients with aplastic anemia whose ages were between seven and 19 yr (median: 12.9 yr). All of the patients completed the desensitization program. While local reaction was seen in two patients, systemic reaction was seen in one patient and late reaction was seen in one patient during and after desensitization program.

CONCLUSION

A successful desensitization program with h-ATG in children with aplastic anemia is presented. Even though there is not an exposure before to such high allergy potential heterologous serum, skin tests should be performed and desensitization must be started to patients who are hypersensitized to h-ATG. As the expected effectiveness of the treatment is so much, the desensitization protocol can be carried out safely and effectively with trained stuff although allergic reactions can be seen.

Desensitization in patients with beta-lactam drug allergy

BACKGROUND

Patients with a history of beta-lactam antibiotic allergy are often admitted to the hospital with severe or life-threatening infections requiring beta-lactam antibiotics. Strict avoidance of beta lactams to such patients may prevent them from getting adequate coverage and can lead to an increase in the use of alternative antibiotics, which can predispose to antibiotic resistance. Past studies revealed a lower incidence of pen allergy then patients' histories suggest. Fortunately today, there are three options for patients presenting with a history of beta-lactam allergy. Penicillin skin testing, beta-lactam challenge or beta-lactam desensitization. Recently Pre Pen has been FDA re-approved and when combined with Pen G is a valid way to determine if patients are able to tolerate beta-lactam antibiotic. When these agents are not available one must decide about desensitization or challenge. When a patient has a positive penicillin skin test, desensitization or beta-lactam avoidance are the only options. This paper reviews the safety of beta-lactam desensitization.

OBJECTIVE

To perform a chart review on patients desensitised with beta lactam to determine if desensitizations can be performed safely without minimal complications.

METHODS

A retrospective chart review was performed on allergy and immunology inpatient consultations for beta-lactam desensitization between September 2003 and August 2006 at the Cedars-Sinai Medical Centre in Los Angeles. Patient data and outcomes of desensitization were analysed.

RESULTS

A total of 13 intravenous desensitizations were performed on 12 patients. The patients consisted of eight females and four males with an average age of 65 years. Age range was 36-92 years old. All 13 intravenous desensitizations were completed without complications. No patient required a slower rate of desensitization or discontinuance of the desensitization. Patients were able to tolerate the initial therapeutic dose of their beta-lactam antibiotic and were then able to complete full therapeutic courses of their antibiotic.

CONCLUSION

Beta-lactam antibiotic sensitivity continues to present a challenging problem for physicians. Patients with drug resistant infections who are unable to obtain skin testing or who test positive to skin tests may need either a challenge or desensitization. Desensitization, saved for those with a convincing beta-lactam hypersensitivity history is often the choice of last resort given the associated cost and risk of anaphylaxis. However, once desensitization is complete, patients are usually able to tolerate full doses of antibiotics for full treatment length with minimal side effects.

Management of multiple drug allergies in children

Children with multiple drug allergies are likely to require treatment with one or more of the drugs to which they may have had a reaction, when there is no alternate effective drug available. Detailed review of their history and/or use of appropriate diagnostic studies will help determine the potential safety of readministering the desired drug as well as the method for its readministration, most likely in the form of a drug challenge or desensitization. A practical approach to the diagnosis and treatment of children with multiple drug allergies is described in this review.

Outpatient aspirin desensitization for patients with aspirin hypersensitivity and cardiac disease

BACKGROUND

Cardiac disease is common and often treated with aspirin therapy. Patients who develop an immunoglobulin E (IgE) hypersensitivity reaction to aspirin must abort treatment and receive alternative antithrombotic agents. Aspirin desensitization is a therapeutic procedure that may allow patients with a history of hypersensitivity to safely resume aspirin treatment. A variety of inpatient desensitization protocols have been published for IgE-mediated reactions, but outpatient regimens have not been previously reported.

OBJECTIVE

We aimed to determine the efficacy and safety of a multiday outpatient aspirin desensitization protocol for patients with an IgE-mediated aspirin hypersensitivity.

METHODS

We retrospectively assessed the efficacy of a multidose aspirin desensitization protocol performed in a university allergy-immunology clinic between July 2006 and December 2009. Patients were referred for a diagnosis of aspirin hypersensitivity and required aspirin for cardiac disease treatment. The protocol involved 10 or 12 aspirin doses depending on the final dose of 81 or 325 mg. Patients were desensitized over 2 to 3 half-days and were able to return home in between desensitization sessions.

RESULTS

A total of 9 patients with cardiac disease and aspirin hypersensitivity underwent an outpatient multiday aspirin desensitization. Eight patients (89%) were successfully desensitized and 1 patient declined to continue with further desensitization. No adverse reactions requiring inpatient hospital care occurred during desensitization.

CONCLUSIONS

This novel outpatient multiday aspirin desensitization protocol was a safe and effective approach for the treatment of aspirin hypersensitivity in patients with cardiac disease who require aspirin therapy. This flexible protocol is convenient for patients by avoiding hospital admission and full-day time commitments.

Novel concepts in evaluating antimicrobial therapy for bacterial lung infections in patients with cystic fibrosis

Cystic fibrosis (CF) patients suffer typically from bacterial infections of their airways. Whilst current antibiotic-based treatment of these infections has brought much benefit to patients, it has been difficult to make either direct or indirect assessments of the in vivo efficacy of any specific treatment used. Traditional culture-based assessment has for example been rarely used to determine the direct impact of therapy on the bacteria in the airways. Instead, the "success" of a treatment is most often gauged through measures of respiratory and general health. New culture-independent approaches though are emerging that offer much promise here however in allowing a more comprehensive evaluation of antimicrobial efficacy. These new methods offer an opportunity to examine bacterial outcomes rather than host outcomes alone. Application of these novel techniques in a systematic way will lead to the rationalisation and, likely greater still individualisation, of therapy for CF patients. This review discusses host and microbiological factors that may influence antibiotic efficacy. Moreover, the degree to which the inherent complexity of CF respiratory infections complicates the process of determining treatment impact and the need to identify more robust microbiological outcome measures will also be reviewed.

Clinical applications of drug desensitization in the Asia-Pacific region

Drug desensitization is the induction, within hours to days, of a temporary state of tolerance to a drug which the patient has developed a hypersensitivity reaction to. It may be used for IgE and non-IgE mediated allergic reactions, and certain non-allergic reactions. The indication for desensitization is where no alternative medications are available for the treatment of that condition, and where the benefits of desensitization outweigh the risks. Desensitization is a therapeutic modality for drug allergy (similar to allergen specific immunotherapy for allergic rhinitis and insect venom anaphylaxis). In contrast, the drug provocation test is a diagnostic modality used to confirm or refute the diagnosis of drug allergy. This review discusses the clinical applications of desensitization for the treatment of common infectious, metabolic and cardiovascular diseases, and oncological conditions in the Asia-Pacific region.

Drug allergy: an updated practice parameter

Adverse drug reactions (ADRs) result in major health problems in the United States in both the inpatient and outpatient setting. ADRs are broadly categorized into predictable (type A and unpredictable (type B) reactions. Predictable reactions are usually dose dependent, are related to the known pharmacologic actions of the drug, and occur in otherwise healthy individuals, They are estimated to comprise approximately 80% of all ADRs. Unpredictable are generally dose independent, are unrelated to the pharmacologic actions of the drug, and occur only in susceptible individuals. Unpredictable reactions are subdivided into drug intolerance, drug idiosyncrasy, drug allergy, and pseudoallergic reactions. Both type A and B reactions may be influenced by genetic predisposition of the patient

General considerations on rapid desensitization for drug hypersensitivity - a consensus statement

Drug hypersensitivity reactions can occur with most drugs, are unpredictable, may affect any organ or system, and range widely in clinical severity from mild pruritus to anaphylaxis. In most cases, the suspected drug is avoided in the future. However, for certain patients, the particular drug may be essential for optimal therapy. Under these circumstances, desensitization may be performed. Drug desensitization is defined as the induction of a temporary state of tolerance of a compound responsible for a hypersensitivity reaction. It is performed by administering increasing doses of the medication concerned over a short period of time (from several hours to a few days) until the total cumulative therapeutic dose is achieved and tolerated. It is a high-risk procedure used only in patients in whom alternatives are less effective or not available after a positive risk/benefit analysis. Desensitization protocols have been developed and are used in patients with allergic reactions to antibiotics (mainly penicillin), insulins, sulfonamides, chemotherapeutic and biologic agents, and many other drugs. Desensitization is mainly performed in IgE-mediated reactions, but also in reactions where drug-specific IgE have not been demonstrated. Desensitization induces a temporary tolerant state, which can only be maintained by continuous administration of the medication. Thus, for treatments like chemotherapy, which have an average interval of 4 weeks between cycles, the procedure must be repeated for every new course. In this paper, some background information on rapid desensitization procedures is provided. We define the drugs and drug reactions indicated for such procedures, describe the possible mechanism of action, and discuss the indications and contraindications. The data should serve as background information for a database (accessible via the EAACI-homepage) with standardized protocols for rapid desensitization for antibiotics, chemotherapeutic agents, monoclonal antibodies/fusion proteins, and other drugs.

Clopidogrel Hypersensitivity: A Novel Multi-Day Outpatient Oral Desensitization Regimen

BACKGROUND

Clopidogrel hypersensitivity has posed a problem for the acute treatment and long-term care of a particular patient population with coronary artery disease and stent placement. Patients with clopidogrel hypersensitivity have had an increased risk of hypersensitivity reactions, including anaphylaxis, if they ingest clopidogrel without undergoing an oral desensitization procedure. The previously published desensitization protocols have either been performed in the intensive care unit, requiring significant cost and healthcare utilization, or have required a full-day outpatient commitment on behalf of the patient.

OBJECTIVE

To determine whether a multi-day outpatient oral clopidogrel desensitization protocol is effective and safe for patients with clopidogrel hypersensitivity.

METHODS

gWe retrospectively assessed the efficacy of a 10-dose outpatient multiday clopidogrel desensitization protocol performed in a university allergy-immunology center from April 2006 to October 2008 in patients with clopidogrel hypersensitivity. Patients were desensitized over 2–3 half-day clinical visits and were able to go home between desensitization sessions. A preliminary cost analysis was performed using the average of actual costs for the outpatient clopidogrel desensitization procedure and was compared with the average cost for an inpatient oral desensitization completed at our institution.

RESULTS

Eight patients with coronary artery disease, cardiac stent placement, and clopidogrel hypersensitivity underwent an outpatient multi-day oral clopidogrel desensitization procedure. All patients were successfully desensitized with the multi-day protocol without complications. No patient had recurrence of allergic reaction 3 months after the procedure. A preliminary cost analysis demonstrated a lower cost for the outpatient compared to the inpatient oral clopidogrel desensitization protocol.

CONCLUSIONS

This outpatient 10-dose multi-day clopidogrel desensitization protocol is a safe and effective novel approach for the treatment of clopidogrel hypersensitivity in patients with coronary artery disease and cardiac stent placement. In addition to safety and efficacy, this protocol offers the patient the convenience of avoiding hospital admission or full-day time commitments.

Clinical practice: drug desensitization in children

Immediate type allergic reactions to medication are potentially life threatening and can hamper drug therapy of several medical conditions. Exact incidence and prevalence data for these reactions in children are lacking. If no alternative drug treatment is available, a desensitization procedure may secure the continuation of necessary therapy. Desensitization is only appropriate in case of a strong suspicion of an IgE-mediated allergic reaction. It should be performed by trained clinicians (allergy specialists) in a hospital setting where treatment of a potential anaphylactic reaction can be done without any delay. In this article, literature describing desensitization procedures for several antibiotics, antineoplastic agents, and vaccines in children is reviewed. In general, desensitization schemes for children differ only in final dose from schemes for adults. Contradictory data were found regarding the protective effects of premedication with antihistamines and glucocorticoids.

A safe protocol for rapid desensitization in patients with cystic fibrosis and antibiotic hypersensitivity

BACKGROUND

CF patients often demonstrate hypersensitivity to one or multiple antibiotics due to frequent and repeated exposures. Attempts at antibiotic desensitization in this population are historically complicated by higher reaction rates, failure to complete the procedure and consequent withholding of first-line therapy. This study evaluates the outcomes of a rapid desensitization protocol developed at our institution.

METHODS

We retrospectively reviewed the medical records of 15 patients undergoing 52 rapid antibiotic desensitizations at Brigham and Women's Hospital and Children's Hospital Boston utilizing our protocol.

RESULTS

Mean FEV1 % predicted was 44.1 (SD 16.5), with two patients at <30% and one patient desensitized during bilateral lung transplantation. Adverse reactions during desensitization occurred in 13.4%, and most were mild. 100% of patients completed the protocol and ultimately tolerated subsequent full-strength antibiotic courses.

CONCLUSIONS

CF patients with antibiotic hypersensitivity can safely receive first-line antibiotics via our rapid desensitization protocol, including those with severe obstructive lung disease.

Antibiotic allergy: immunochemical and clinical considerations

Antibiotics are among the most widely and heavily prescribed drugs, but despite this, allergic reactions to most groups of antibiotics are relatively uncommon-especially when compared with the number and frequency of type 1 hypersensitivity responses to the beta-lactams (ie, penicillins, cephalosporins, and, to a lesser extent, carbopenems). Still, there remains a steady flow of reports of allergic reactions to some topically used antibiotics (eg, rifamycin SV and bacitracin). Moreover, aminoglycosides (eg, neomycin and gramicidin) may be implicated more often than previously suspected. Despite advances in our understanding of the structural basis of the allergenicity of beta-lactam antibiotics, the insights have not readily transferred into routine use to improve diagnoses of reactions to individual penicillins and cephalosporins. This remains a challenge in drug allergy, as does the need for further chemical, immunologic, and clinical research on cephalosporin breakdown products and the so-called multiple antibiotic allergy syndrome.

Specific oral tolerance induction in children with very severe cow's milk-induced reactions

BACKGROUND

Some children allergic to cow's milk proteins (CMPs) experience exceptionally severe reactions after ingesting only trace amounts of antigen. Avoiding the food and carrying self-injectable epinephrine are the current strategies for their management.

OBJECTIVE

The aim of this study was to evaluate the safety and efficacy of specific oral tolerance induction (SOTI) for children with severe CMP-induced systemic reactions.

METHODS

Ninety-seven children aged 5 years or older with a history of severe allergic reactions and very high CMP-specific IgE levels were selected for a double-blind, placebo-controlled food challenge. Sixty had positive test results to very small amounts of milk and were randomly divided in 2 different groups. Thirty children (group A) immediately began SOTI, whereas the remaining 30 (group B) were kept on a milk-free diet and followed for 1 year.

RESULTS

After 1 year, 11 (36%) of 30 children in group A had become completely tolerant, 16 (54%) could take limited amounts of milk (5-150 mL), and 3 (10%) were not able to complete the protocol because of persistent respiratory or abdominal complaints. In group B the result of the double-blind, placebo-controlled food challenge performed after a year was positive in all 30 cases (P < .001).

CONCLUSIONS

In this study SOTI was effective in a significant percentage of cases.

Desensitization for drug allergy

PURPOSE OF REVIEW

Desensitization for drug allergy is the induction of temporary clinical unresponsiveness to drug antigens. Gradual reintroduction of small doses of drug antigen at fixed time intervals allows for the delivery of full therapeutic doses, protecting patients from anaphylaxis. Rapid desensitizations permit the use of essential antibiotics in severely infected allergic patients or aspirin in aspirin-sensitive cardiac patients undergoing revascularization. We review the indications and outcomes of recent protocols for desensitization to antibiotics and aspirin.

RECENT FINDINGS

Despite the success of rapid desensitizations, the cellular and molecular inhibitory mechanisms are incompletely understood. In-vitro mast cell and basophil models implicate molecular signaling molecules syk and STAT6. Rapid desensitization protocols treat type I mast cell/IgE dependent reactions, such as anaphylaxis, as seen with sensitization to penicillin, cephalosporins, and other antibiotics. Anaphylactoid reactions induced upon initial drug exposure and with similar clinical presentation as immunoglobulin E-mediated reactions, as seen with aspirin, vancomycin and taxenes, can also be treated with rapid desensitizations.

SUMMARY

Successful rapid desensitization protocols for treating adverse reactions to antibiotics and aspirin allow for treatment of critically infected patients and aspirin-sensitive cardiac patients. Standardized protocols with high success rates should be implemented as the standard of care.

Rapid desensitization for hypersensitivity reactions to chemotherapy agents

PURPOSE OF REVIEW

Hypersensitivity reactions (HSRs) to chemotherapy agents have limited their use for fear of inducing severe reactions or death. Alternative regimens may be limited by tumor sensitivity and the need to provide first-line therapy. Rapid desensitizations allow patients to be treated with medications to which they have presented a HSR. The purpose of this review is to highlight the indications and recent developments in chemotherapy rapid desensitization protocols.

RECENT FINDINGS

Intravenous and oral rapid desensitization protocols are available for taxenes, platinums, doxorubicin, monoclonal antibodies and others. Candidate patients present mild to severe type I hypersensitivity, mast cell/IgE-dependent reactions, as seen with platinums. Anaphylactoid reactions, such as those with taxenes, can be treated with the same protocols. Repeat desensitizations in outpatient settings are well tolerated and allow patients to remain in clinical studies/trials. Breakthrough symptoms during desensitizations are less severe than the initial reaction and no deaths have been reported. Cancer remissions are similar to those for nondesensitized patients.

SUMMARY

The use of rapid desensitization protocols for cancer patients with HSRs to chemotherapy depends on their demonstrated tolerability and efficacy in selected populations. Education of nurses, pharmacists, and oncology and allergy specialists is needed to improve their universal application as standard of care.

Intravenous Linezolid Administered Orally: A Novel Desensitization Strategy

A 41-year-old woman with a history of myasthenia gravis was admitted to a local hospital because of severe muscle weakness, ptosis, shortness of breath, nausea and vomiting, and fever. Blood cultures revealed Enterococcus faecium resistant to several antimicrobial agents. The organism had minimum inhibitory concentrations above 16 microg/ml for vancomycin and above 2 microg/ml for quinupristin-dalfopristin. In the absence of therapeutic alternatives, treatment with linezolid was required (minimum inhibitory concentration 1.5 microg/ml). The first dose of linezolid resulted in a hypersensitivity reaction consistent with an immunoglobulin E-mediated response requiring medical intervention. Because of a lack of intravenous access and because of limited availability of the oral suspension from the manufacturer, a desensitization protocol was implemented in which the intravenous formulation of linezolid was given orally. The patient was successfully desensitized by using an escalating, 14-dose procedure. We believe this is the first case in the English language literature to describe successful desensitization with the oral administration of intravenous linezolid in a patient with E. faecium bacteremia who was allergic to oxazolidinone.

Drug hypersensitivity

Allergic drug reactions compose a small percentage of ADRs, yet they are commonly encountered in clinical practice, and physicians are taught routinely to question patients about these reactions during history taking. Among antibiotics, the immunochemistry of penicillins has been elucidated,leading to the development of validated skin test reagents to diagnose type 1 allergy. Currently, the temporary commercial unavailability of Pre-Pen makes accurate penicillin skin testing impossible; however, this important skin test reagent is expected to become available sometime in 2006. Type 1 allergies to most other drugs lack comparable diagnostic tests, and their diagnosis is therefore driven by the patient's history. When readministration of medications to which patients report previous reactions is indicated, it may be almost always successfully accomplished by means of either graded challenge or desensitization.