Epidemic Thunderstorm Asthma in China: A Systematic Review of an Artemisia-Associated Phenotype

Epidemic thunderstorm asthma (ETSA) has historically been characterised around grass pollen in temperate Australia and Europe, whereas reports from northern China suggest an Artemisia-associated and potentially recurrent pattern. This systematic review synthesises primary evidence on the epidemiology, allergen profile, clinical features and early-warning systems of ETSA, comparing the Chinese and grass-pollen experiences. Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 statement, PubMed, Web of Science, the China National Knowledge Infrastructure (CNKI) and Wanfang were searched to 30 June 2026, and reference lists were screened. Two reviewers independently selected studies, extracted data and assessed risk of bias with the Newcastle-Ottawa Scale and the Murad tool; certainty was rated using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. Because of clinical and methodological heterogeneity, no meta-analysis was performed. Of 436 records identified and 333 screened after de-duplication, 54 primary studies were included (43 international and 11 Chinese, spanning Yulin, Hohhot, Chongqing, Lanzhou and Shenzhen). Three recurring observational patterns were identified. Chinese reports, especially from northern and north-western China, frequently described mugwort (Artemisia) sensitisation rather than ryegrass sensitisation; the proportion without a prior asthma diagnosis was high in both settings (approximately 40% to 60% in China and up to 60% to 78% in Australian and United Kingdom cohorts); and recurrent events were reported at individual Chinese localities. Most Chinese reports used genus-level Artemisia or mugwort sensitisation and did not identify the airborne pollen to species. Evidence for direct Artemisia pollen rupture, pollution-related severity modification and pre-emptive treatment was low or very low. Priority research includes field aerosol sampling, prospective validation of locally calibrated warning systems, and trials of pre-emptive inhaled therapy.