Blastocystis and chronic urticaria: the evidence reviewed does not justify routine testing or treatment

Ulusan Bagci et al. propose Blastocystis spp. as a hidden cause of chronic urticaria and suggest routine stool testing and treatment in positive cases. We argue that this conclusion is not supported by the current evidence, which is dominated by heterogeneous diagnostics, cross-sectional prevalence comparisons prone to misclassification, and non-randomised treatment-response reports lacking clearance-linked endpoints. We outline minimum standards for interpretable inference, including quantitative detection, longitudinal sampling, and trials linking confirmed clearance versus persistence to validated urticaria outcomes.