Early low-dose dexamethasone is associated with shorter acute symptom duration in Chikungunya virus infection: a retrospective cohort study.

BACKGROUND: Chikungunya virus (CHIKV) causes acute febrile illness with severe arthralgia; management is largely supportive and corticosteroid use remains controversial. We evaluated whether early, short-course, low-dose dexamethasone was associated with shorter acute symptom duration during the 2019 Bangkok outbreak. METHODS: We retrospectively analyzed 187 adults with confirmed CHIKV and severe arthralgia. Thirty-nine received dexamethasone 4 mg/day for 3 days within ≤ 48 h of symptom onset plus standard care; 148 received standard care alone. Primary outcomes were duration of the acute febrile phase and duration of rheumatic manifestations abstracted from records and patient reports. Secondary outcomes included C-reactive protein (CRP) and adverse events. Follow-up laboratory tests occurred at clinician discretion and were summarized in early (days 3-5) and late (days 6-8) windows. RESULTS: The dexamethasone group had shorter acute febrile phase (median 3 vs. 5 days, p < 0.001) and rheumatic manifestations (7 vs. 10 days, p < 0.001). At late follow-up, median CRP was lower (20 vs. 35 mg/L, p < 0.001). Adverse events were uncommon and similar (gastrointestinal discomfort 5% vs. 3%, p = 0.45). CONCLUSIONS: In this retrospective cohort, early, short-course, low-dose dexamethasone was associated with shorter acute symptom duration and lower inflammatory markers without an observed increase in adverse events. Randomized trials are warranted to determine efficacy, safety, and generalizability. CLINICAL TRIAL: This study was registered with the Thai Clinical Trials Registry (TCTR20201022004) on 22 October 2020.