DRUG HYPERSENSITIVITY REACTIONS: FROM MOLECULAR MECHANISMS TO CLINICAL SOLUTIONS

Drug hypersensitivity reactions represent one of the most complex and rapidly evolving areas of allergy and clinical immunology. Their clinical manifestations range from mild, self-limited reactions to life-threatening anaphylaxis and severe cutaneous adverse reactions, while the underlying mechanisms encompass diverse immunological and non-immunological pathways. Despite major advances in our understanding of these mechanisms and in diagnostic and therapeutic approaches, translating this expanding knowledge into consistent clinical practice remains challenging. Drug Hypersensitivity Reactions: From Molecular Mechanisms to Clinical Solutions was conceived to address this challenge. The primary aim of this book is to provide an integrated and clinically relevant overview of drug hypersensitivity, bridging fundamental immunological mechanisms with diagnosis, risk assessment, management, prevention, and therapeutic decision-making. Rather than approaching molecular mechanisms and clinical practice as separate domains, the book follows a translational perspective, demonstrating how advances in immunology can inform the evaluation and management of individual patients. An important gap in the existing literature is the fragmentation of knowledge across different drug classes, reaction phenotypes, age groups, and areas of expertise. Mechanistic discoveries are not always readily translated into diagnostic algorithms, while clinical guidance may not fully reflect the biological heterogeneity underlying apparently similar reactions. Furthermore, pediatric and adult drug hypersensitivity are frequently discussed separately, despite sharing fundamental mechanisms and diagnostic principles while presenting important age-specific differences. This book seeks to bring these perspectives together within a unified framework. A distinctive feature of this volume is therefore its lifespan approach to drug hypersensitivity. The chapters have been contributed by experts with extensive experience in both pediatric and adult allergy and immunology. We aim to provide a more comprehensive understanding of drug hypersensitivity across the entire spectrum of clinical practice. The book also places particular emphasis on the transition from mechanism to clinical solution. Contemporary concepts of immune recognition and activation are connected with clinical phenotypes, biomarkers, in vivo and in vitro diagnostic methods, drug provocation testing, cross-reactivity, avoidance strategies, delabeling, and drug desensitization. Emerging diagnostic and therapeutic approaches are considered alongside established practices, with attention to both their potential and their current limitations. In doing so, the book aims not merely to summarize available knowledge, but to organize it into a framework that supports clinical reasoning and evidence-based decision-making. This volume is intended for both adult and pediatric allergists and clinical immunologists, internists, pediatricians, dermatologists, pharmacologists, infectious disease specialists, and other physicians who encounter suspected drug hypersensitivity reactions in their practice. We also hope that it will serve as a useful reference for fellows, residents, researchers, and post-graduate students seeking to understand the biological foundations of drug hypersensitivity and their clinical implications. For experienced clinicians, the book offers an updated synthesis of a rapidly developing field; for trainees and researchers, it provides a structured pathway from fundamental concepts to real-world clinical problems. Our intention in preparing this book has been to create a resource that connects disciplines, age groups, and levels of knowledge. Drug hypersensitivity is inherently multidisciplinary, and meaningful progress requires interaction between mechanistic research and clinical observation, as well as between specialists caring for children and those caring for adults. We hope that this book will contribute to that interaction, encourage critical evaluation of current practices, and ultimately support safer, more precise, and more individualized care for patients with suspected or confirmed drug hypersensitivity. We are deeply grateful to all contributing authors for sharing their expertise and for bringing together diverse scientific and clinical perspectives. Their contributions have made it possible to develop a volume that reflects both the complexity of drug hypersensitivity and the collaborative approach required to address it. Editors Semra DEMİR MD, PhD, Professor Deniz ÖZÇEKER MD, Professor