Immediate hypersensitivity to herbal medicine: from diagnosis to policies

In recent years, the global consumption of herbal medicines has been increasing, accompanied by increasing reports of immediate hypersensitivity reactions (IHRs). Given the potential impact on patient safety, there is an increasing need to tighten regulations on herbal medicine use to reduce the incidence of herbal medicine-induced IHRs. Hence, this review consolidates current evidence on the pathophysiological mechanisms, clinical manifestations, and regulatory responses related to IHRs caused by herbal medicines, before providing perspectives for future research in diagnosis, pharmacovigilance, and policymaking.

Immunoglobulin E (IgE)-mediated and non-IgE-mediated mechanisms are implicated in IHRs. Bioactive constituents and impurities in herbal medicines have been identified as possible causes of IHRs. Clinically, herbal-induced IHRs present with cutaneous, respiratory, and systemic symptoms that may progress to anaphylaxis. Regulatory bodies worldwide have implemented regulatory frameworks and pharmacovigilance systems, however there is still room for improvement.

IHRs to herbal medicines represent a growing safety concern in integrative healthcare. Future research should emphasize mechanistic characterization, improved pharmacovigilance, and well-planned regulation on herbal medicines. Strengthening clinician awareness and adverse-event reporting will be critical to safeguarding patients and ensuring the evidence-based integration of herbal medicines into modern medical practice.