Evolution Pattern of High-Altitude Headache: A Prospective Observational Study upon Rapid Ascent to 4300 m

Introduction Headache is the most common symptom of altitude exposure. However, there have been few studies to observe the evolution and outcomes of high-altitude headache (HAH), and its relationship to acute mountain sickness (AMS), especially following rapid air transport to extreme altitudes. Methods Chinese Han workers who ascended from Lanzhou (1500 m) to the Ali region (4300 m) on the Tibetan Plateau were prospectively studied between March 2023 and May 2025. Clinical features and evolution of altitude headache observed in this cohort at 4300 m were recorded using standardized questionnaires incorporating both the International Classification of Headache Disorders (ICHD-3) and the 2018 Lake Louise Score (LLS) criteria. Results Of the 159 workers, 106 (66.7%) reported headaches on Day 1; the headaches were predominantly bilateral (79.2%) and mild to moderate in intensity (90.5%). Among the 106 participants with headache, 91 (85.8%) fulfilled the LLS criteria for AMS at the same Day 1 assessment. Headache intensity was significantly greater in subjects with AMS compared to those with isolated headache ( P = 0.003), but no other headache characteristic differed between groups. The incidence of headache peaked on Day 1 (66.7%) and gradually declined to 0.6% on Day 7, with a median headache duration of 3 days. Conclusions HAH presents a self-limiting course following acute exposure to high altitude. The clinical overlap with AMS suggests they may reflect different severity of illness rather than separate processes.