The escalating global burden of drug allergies demands a paradigm shift from broad symptom descriptions to precision diagnostics.¹ With up to 15% of the global population labeled as allergic to beta-lactam (BL) antibiotics, healthcare systems face surging costs, prolonged hospitalizations, and a severe antimicrobial resistance crisis.² At the Hong Kong Institute of Allergy (HKIA) Annual Scientific Meeting 2026, Immediate Past President of the European Academy of Allergy and Clinical Immunology (EAACI) Professor María José Torres Jaén explained that addressing this requires a unified nomenclature that distinctly categorizes these adverse reactions into drug-antigen-driven allergies and drug-directly-driven hypersensitivities.¹ By integrating structured clinical decision rules, clinicians can potentially risk-stratify patients and remove inaccurate allergy labels.^3-5

Mislabeling patients as allergic to penicillin has considerable clinical and economic consequences, with clinicians prescribing less effective treatment, increased antibiotic resistance, and higher healthcare utilization costs, supporting the urgent need for precise diagnostic frameworks.² To manage the complexities of adverse drug reactions, a modernized nomenclature has been proposed to distinguish clinical phenotypes from their underlying biological mechanisms, or endotypes.^1,6 Under this proposed framework, reactions are classified into two primary categories based on their underlying mechanisms.¹ Drug-antigen-driven reactions occur when small molecular drugs bind non-covalently to host proteins, forming adducts that can be processed by antigen-presenting cells and trigger an adaptive immune response.^1,6 In contrast, drug-directly-driven reactions involve direct interactions with immune receptors (e.g. MRGPRX2) or inflammatory pathways without prior sensitization.^1,6

Despite recent proposals to standardize drug allergy nomenclature, broader international harmonization of the terms "allergy" and "hypersensitivity" remains an ongoing process.^4,6 Some frameworks use the terms interchangeably, while others use "hypersensitivity" as an umbrella term encompassing immune-mediated allergic reactions and non-immune-mediated reactions.⁴ Importantly, allergic reactions can be immediate or delayed, depending on the underlying mechanism and clinical presentation.⁴ An international task force led by Dr. Phillip Li Hei from the University of Hong Kong is currently leading the development of harmonized global definitions, with consensus recommendations expected to be ready early next year.

Addressing the global burden of drug allergies is complicated by a severe shortage of trained allergists, making it unsustainable to rely exclusively on specialists for the delabeling process.² Empowering non-allergists to perform systematic risk stratification is essential to safely clear low-risk patients at the point of care.² In Europe, PEN-FAST is a validated clinical decision rule that enables point-of-care risk assessment for adults with penicillin allergy.³ Newer tools such as the BL-predictor serve as a user-friendly way to detect low-risk beta-lactam allergy.¹  In the Asia-Pacific region, risk assessment is guided by the Asia Pacific Association of Allergy, Asthma and Clinical Immunology (APAAACI) clinical pathway, which triages patients to safely undergo direct drug provocation testing based on their clinical history.⁵

The APAAACI pathway consists of a collaborative "hub-and-spoke" model that relies on risk stratification to direct patients to the appropriate clinical pathway.⁵ Patients with strictly low-risk features, such as an unknown or untraceable history of a reaction occurring more than one year previously, isolated gastrointestinal symptoms, or a family history of penicillin allergy alone, may be suitable for direct drug provocation testing (DPT) at local "spoke" centers, which are run by trained non-allergists without dedicated allergy services.⁵ These spokes operate under the guidance of specialized "hub" centers that provide training, support, and direct assessment for more complex cases.⁵ Individuals exhibiting high-risk indicators—such as anaphylaxis, severe cutaneous adverse reactions, or respiratory compromise—are excluded from direct DPT at spoke centers and must be evaluated by allergy specialists at the hubs.⁵ Finally, for patients with ambiguous "other features," like a recent non-urticarial rash or throat tightness, the decision to safely test at a local spoke or refer to a specialized hub is determined through collaborative, shared decision-making between clinicians at both facilities.⁵

For patients with moderate- to high-risk histories, advanced in vitro diagnostics may provide additional information and help guide decisions about further testing.¹ Novel multivalent dendrimeric scaffolds that mimic drug-protein conjugates, combined with magnetic nanoparticles in immunoassays, are being investigated to improve the detection of immunoglobulin E (IgE) associated with penicillin allergy.¹ In oncology, cellular diagnostics such as basophil activation tests (BATs) and mast cell activation tests (MATs) use markers including CD63 and CD203c to investigate hypersensitivity reactions to chemotherapy agents like carboplatin and oxaliplatin.¹ Their potential roles in risk assessment and drug desensitization are being explored, although clinical utility varies by drug and application.¹ Emerging point-of-care platforms incorporating silicon photonics and immunochemical methods are also being investigated for rapid testing of antibiotics such as amoxicillin and penicillin G, though further validation is needed to establish their clinical utility.¹

Leveraging these risk stratification tools and advanced in vitro diagnostics allows healthcare systems to safely delabel low-risk patients, reducing unnecessary therapeutic restrictions and alleviating the broader public health crisis of antimicrobial resistance.^1-3 Furthermore, the development of innovative point-of-care devices and advanced in vitro diagnostics, such as BAT, equips both specialists and non-allergists to safely navigate complex hypersensitivities.^1,2 Ultimately, this unified diagnostic approach ensures patients receive optimal therapies.¹