Precision medicine in allergic disease-food allergy, drug allergy, and anaphylaxis-PRACTALL document of the European Academy of Allergy and Clinical Immunology and the American Academy of Allergy, Asthma and Immunology

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.

Safety and Outcomes of Oral Graded Challenges to Amoxicillin without Prior Skin Testing

BACKGROUND

Unconfirmed penicillin allergy poses substantial public health consequences. The most widely accepted protocol to evaluate penicillin allergy is skin testing followed by an amoxicillin challenge.

OBJECTIVE

To evaluate the safety of direct oral graded challenges to amoxicillin.

METHODS

A prospective single-blind clinical trial with historical controls of patients ≥7 years old with historical non-life-threatening reactions to penicillin was conducted. Patients received placebo followed by a 2-step graded challenge to amoxicillin. The allergic reaction rate was compared with the rate observed in our previous study that included skin testing and with the currently reported penicillin allergy prevalence in the US population.

RESULTS

Of the 155 participants who completed an amoxicillin challenge, 120 patients (77.4%) experienced no reaction whereas 31 patients (20%) experienced nonallergic reactions to either placebo (n = 16) or amoxicillin (n = 15). Four patients (2.6%) developed mild allergic reactions. Significantly (P = .03) fewer patients (4 of 155, 2.6%, 95% confidence interval [CI]: 1.0%, 6.5%) were determined to be allergic compared with 14 of 170 subjects (8.2%, 95% CI: 5.0%, 13.4%) in our previous study where patients were determined to be allergic based on either positive skin tests (n = 11) or allergic challenge reactions after negative skin tests (n = 3). This 2.6% reaction rate was also significantly less than the 10% reported US prevalence of penicillin allergy (P = .003).

CONCLUSIONS

Placebo-controlled oral graded challenges to amoxicillin without prior skin testing may be safe for patients ≥7 years old with non-life-threatening historical reactions to penicillin. Amoxicillin can be tolerated by the majority of patients with self-reported penicillin 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.

Advances in the approach to the patient with food allergy

Advances in food allergy diagnosis, management, prevention, and therapeutic interventions have been significant over the past 2 decades. Evidence-based national and international guidelines have streamlined food allergy diagnosis and management, whereas paradigm-shifting work in primary prevention of peanut allergy has resulted in significant modifications in the approach to early food introduction in infants and toddlers. Innovative investigation of food allergy epidemiology, systems biology, effect, and management has provided important insights. Although active therapeutic approaches to food allergy remain experimental, progress toward licensed therapies has been substantial. Mechanistic understanding of the immunologic processes underlying food allergy and immunotherapy will inform the future design of therapeutic approaches targeting the food-induced allergic response. Global strategies to mitigate the substantial medical, economic, and psychosocial burden of food allergy in affected subjects and families will require engagement of stakeholders across multiple sectors in research, health care, public health, government, educational institutions, and industry. However, the relationship between the well-informed allergy care provider and the patient and family remains fundamental for optimizing the care of the patient with food allergy.

Regulatory Immune Mechanisms in Tolerance to Food Allergy

Oral tolerance can develop after frequent exposure to food allergens. Upon ingestion, food is digested into small protein fragments in the gastrointestinal tract. Small food particles are later absorbed into the human body. Interestingly, some of these ingested food proteins can cause allergic immune responses, which can lead to food allergy. So far it has not been completely elucidated how these proteins become immunogenic and cause food allergies. In contrast, oral tolerance helps to prevent the pathologic reactions against different types of food antigens from animal or plant origin. Tolerance to food is mainly acquired by dendritic cells, epithelial cells in the gut, and the gut microbiome. A subset of CD103⁺ DCs is capable of inducing T regulatory cells (Treg cells) that express anti-inflammatory cytokines. Anergic T cells also contribute to oral tolerance, by reducing the number of effector cells. Similar to Treg cells, B regulatory cells (Breg cells) suppress effector T cells and contribute to the immune tolerance to food allergens. Furthermore, the human microbiome is an essential mediator in the induction of oral tolerance or food allergy. In this review, we outline the current understanding of regulatory immune mechanisms in oral tolerance. The biological changes reflecting early consequences of immune stimulation with food allergens should provide useful information for the development of novel therapeutic treatments.

Perspectives in allergen immunotherapy: 2017 and beyond

The Future of the Allergists and Specific Immunotherapy (FASIT) workshop provides a regular platform for global experts from academia, allergy clinics, regulatory authorities and industry to review developments in the field of allergen immunotherapy (AIT). The most recent meeting, held in February 2017, had two main themes: advances in AIT and hot topics in AIT from the regulatory point of view. The first theme covered opportunities for personalized AIT, advances in adjuvants and delivery systems, and the development of new molecules and future vaccines for AIT. Key topics in the second part of the meeting were the effects of the enactment of European Directive 2001/83 on the availability of allergens for therapy and diagnosis across the EU, the challenges of conducting Phase 3 studies in the field, the future role of allergen exposure chambers in AIT studies and specific considerations in performing AIT studies in the paediatric population. Finally, the group highlighted the forthcoming EAACI guidelines and their particular importance for the standardization of practice in the treatment of allergies. This review presents a comprehensive insight into those panel discussions and highlights unmet needs and also possible solutions to them for the future.

Food allergy: A review and update on epidemiology, pathogenesis, diagnosis, prevention, and management

This review provides general information to serve as a primer for those embarking on understanding food allergy and also details advances and updates in epidemiology, pathogenesis, diagnosis, and treatment that have occurred over the 4 years since our last comprehensive review. Although firm prevalence data are lacking, there is a strong impression that food allergy has increased, and rates as high as approximately 10% have been documented. Genetic, epigenetic, and environmental risk factors are being elucidated increasingly, creating potential for improved prevention and treatment strategies targeted to those at risk. Insights on pathophysiology reveal a complex interplay of the epithelial barrier, mucosal and systemic immune response, route of exposure, and microbiome among other influences resulting in allergy or tolerance. The diagnosis of food allergy is largely reliant on medical history, tests for sensitization, and oral food challenges, but emerging use of component-resolved diagnostics is improving diagnostic accuracy. Additional novel diagnostics, such as basophil activation tests, determination of epitope binding, DNA methylation signatures, and bioinformatics approaches, will further change the landscape. A number of prevention strategies are under investigation, but early introduction of peanut has been advised as a public health measure based on existing data. Management remains largely based on allergen avoidance, but a panoply of promising treatment strategies are in phase 2 and 3 studies, providing immense hope that better treatment will be imminently and widely available, whereas numerous additional promising treatments are in the preclinical and clinical pipeline.

Drug Hypersensitivity and Anaphylaxis in Cancer and Chronic Inflammatory Diseases: The Role of Desensitizations

Drug allergy is a rising problem in the twenty-first century which affects all populations and races, children, and adults, and for which the recognition, diagnosis, management, and treatment is still not well standardized. Classical and new chemotherapy drugs, monoclonal antibodies (MoAbs), and small molecules to treat cancer and chronic inflammatory diseases are aimed at improving quality of life and life expectancy of patients, but an increasing number of reactions including anaphylaxis precludes their use in targeted populations. Women are more affected by drug allergy and up to 27% of women with ovarian and breast cancer develop carboplatin allergy after multiple cycles of treatment. Carriers of BRCA genes develop drug allergy after fewer exposures and can present with severe reactions, including anaphylaxis. Atopic patients are at increased risk for chemotherapy and MoAbs drug allergy and the current patterns of treatment with recurrent and intermittent drug exposures may favor the development of drug allergies. To overcome drug allergy, desensitization has been developed, a novel approach which provides a unique opportunity to protect against anaphylaxis and to improve clinical outcomes. There is evidence that inhibitory mechanisms blocking IgE/antigen mast cell activation are active during desensitization, enhancing safety. Whether desensitization modulates drug allergic and anaphylactic responses facilitating tolerance is currently being investigated. This review provides insight into the current knowledge of drug allergy and anaphylaxis to cancer and chronic inflammatory diseases drugs, the mechanisms of drug desensitization and its applications to personalized medicine.

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.

Immune monitoring for precision medicine in allergy and asthma

'Precision Medicine' embodies the analyses of extensive data collected from patients and their environments to identify and apply patient-specific prophylactic strategies and medical treatments to improve clinical outcomes and healthcare cost-effectiveness. Many new methods have been developed for evaluating the activity of the human immune system. Such 'immune monitoring' approaches are now being used in studies of allergy and asthma in the hope of identifying better correlates of disease status, predictors of therapeutic outcomes, and potential side-effects of treatment. Together with analyses of family histories, genetic and other biometric data, and measurements of exposures to environmental and other risk factors for developing or exacerbating disease, immune monitoring approaches promise to enable 'Precision Medicine' for allergic diseases and asthma.

Diagnosis and management of anaphylaxis in precision medicine

Anaphylaxis is the most severe and frightening of the allergic reactions, placing patients at high risk and demanding prompt recognition and immediate management by health care providers. Yet because its symptoms imitate those of other diseases, such as asthma and urticaria, current data suggest that its diagnosis is often missed, with underuse of tryptase measurement; its treatment is delayed, with little use of epinephrine; and its underlying cause or causes are poorly investigated. Deaths from anaphylaxis are difficult to investigate because of miscoding. Surprisingly, patients treated with new and powerful chemotherapy agents and humanized mAbs present with nonclassical symptoms of anaphylaxis, and patients may present with unrecognized clonal mast cell disorders with KIT mutations may present as Hymenoptera-induced or idiopathic anaphylaxis. The goal of this review is to recognize the presentations of anaphylaxis with the description of its current phenotypes, to provide new insight and understanding of its mechanisms and causes through its endotypes, and to address its biomarkers for broad clinical use. Ultimately, the aim is to empower allergists and heath care providers with new tools that can help alleviate patients' symptoms, preventing and protecting them against anaphylaxis.

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.

Beyond IgE-When Do IgE-Crosslinking and Effector Cell Activation Lead to Clinical Anaphylaxis?

Anaphylaxis in humans is inherently difficult to study due to the acuteness of symptoms and the lack of biomarkers serving as risk predictors. Most cases are related to IgE sensitizations to foods, insect venoms, and drugs with mastocytosis patients forming a smaller risk group. However, identifying the relatively small fraction of persons at risk has been exceedingly difficult. In this review, we propose to describe anaphylaxis in a broader context than defined by IgE sensitization alone. Exposure to a trigger, such as an allergen, may lead to anaphylaxis, but in particular, the internal dose sensed by the immune system needs to be established. Moreover, intrinsic patient factors as well as the specific circumstances of the exposure, i.e., the extrinsic factors, need to be thoroughly accounted for. More controversially, other triggers of anaphylaxis, such as increased sensitivity to or reduced catabolism of histamine (“histamine intolerance”) or mast cell activation syndrome also named mast cell activation disorder have been suggested, but still with very limited epidemiological evidence that a significant proportion of the observed reactions are caused by these alleged conditions. Thus, when all conditions are considered, it seems as if IgE-mediated reactions are responsible for the vast majority of anaphylactic conditions.

Biomarkers in inflammometry pediatric asthma: utility in daily clinical practice

Asthma is a common disease in both high and lower income countries that starts early and persists often for life. A correct and accurate diagnosis, treatment and follow-up during childhood are essential for a better understanding of adult asthma and avoiding over- or under-treatment. Th2 inflammation in children with asthma symptoms is usually assessed by measuring with serum total IgE, blood eosinophilia and FeNO levels that may help to predict asthma, particularly in those infants and young children in whom lung function tests are difficult to perform. FeNO measurement, compared to intra-individual levels, may be useful also for ascertaining treatment adherence. Nevertheless, an isolated measurement may be insufficient and only the combination of these markers improves the diagnosis, phenotyping and follow-up of an asthmatic child.

Diagnosing allergic sensitizations in the third millennium: why clinicians should know allergen molecule structures

Diagnostic tests to detect allergic sensitization were introduced at the end of the nineteenth century but only in the late 1990s did the advent of molecular allergology revolutionize the approach to the allergic patient. Personalized Medicine, a medical procedure that separates patients into different groups with different medical decisions, practices and interventions has sanctioned this change. In fact, in the last few years molecular allergology and the observation that not every patient has the same allergic profile, even when allergic to the same allergenic source, has originated the concept "one size does not fit all". This new approach requires the identification of still unknown allergens, but also the more detailed investigation of those already known. In depth studies of the structure-function relationships in allergenic molecules can reveal the structural determinants involved in the IgE-binding. Then, the knowledge of the epitope profile of each allergen and of the environmental/experimental conditions affecting the exposure of IgE-binding epitopes can provide important contributions to the understanding of cross-reaction processes and to the improvement of diagnosis, immunotherapy and the overall patient treatment. The evolution of diagnostic systems cannot ignore these new needs in this field.

Pro and Contra: Provocation Tests in Drug Hypersensitivity

Drug provocation test (DPT) is the controlled administration of a drug to diagnose immune- or non-immune-mediated drug hypersensitivity and the last step for accurate recognition of drug hypersensitivity reactions when the previous diagnostic evaluations are negative or unavailable. A DPT is performed only if other conventional tests fail to yield conclusive results. In each clinical presentation, "to provoke or not to provoke" a patient should be decided after careful assessment of the risk-benefit ratio. Well-defined benefits of DPT include confirmative exclusion of diagnoses of drug hypersensitivity and provision of safe alternatives. However, disadvantages such as safety, difficulty in interpretations of results, lack of objective biomarkers, risks of resensitization, efficiency in daily practice, and lack of standardized protocols, are poorly debated. This review summarizes the current published research concerning DPT, with particular emphasis on the advantages and disadvantages of DPT in an evidence-based manner.

Drug Hypersensitivity and Desensitizations: Mechanisms and New Approaches

Drug hypersensitivity reactions (HSRs) are increasing in the 21st Century with the ever expanding availability of new therapeutic agents. Patients with cancer, chronic inflammatory diseases, cystic fibrosis, or diabetes can become allergic to their first line therapy after repeated exposures or through cross reactivity with environmental allergens. Avoidance of the offending allergenic drug may impact disease management, quality of life, and life expectancy. Precision medicine provides new tools for the understanding and management of hypersensitivity reactions (HSRs), as well as a personalized treatment approach for IgE (Immunoglobuline E) and non-IgE mediated HSRs with drug desensitization (DS). DS induces a temporary hyporesponsive state by incremental escalation of sub-optimal doses of the offending drug. In vitro models have shown evidence that IgE desensitization is an antigen-specific process which blocks calcium flux, impacts antigen/IgE/FcεRI complex internalization and prevents the acute and late phase reactions as well as mast cell mediator release. Through a "bench to bedside" approach, in vitro desensitization models help elucidate the molecular pathways involved in DS, providing new insights to improved desensitization protocols for all patients. The aim of this review is to summarize up to date information on the drug HSRs, the IgE mediated mechanisms of desensitization, and their clinical applications.