COVID-19 Infection vs Vaccination and the Risk of New-onset Psoriasis.

Emerging evidence has suggested a link between new-onset psoriasis and both COVID-19 infection and vaccination, though findings have been limited by small case numbers and lack of adequate control groups. This retrospective cohort study used electronic health records from the US Collaborative Network of TriNetX from January 2020 to January 2025 to compare the risk of developing new-onset psoriasis in individuals with confirmed COVID-19 infection and no vaccination history vs those vaccinated without prior infection. Propensity score matching was applied to balance demographics, comorbidities, and psoriasis risk factors. The primary outcome was a new diagnosis of psoriasis (ICD10-CM: L40.0-5) within 3 months following infection or vaccination. Subgroup analyses assessed the specific codes L40.0-5 separately. Kaplan-Meier survival analysis and Cox proportional hazards models were used to compare outcomes. Patients with COVID-19 infection had a significantly higher risk of developing psoriasis compared with vaccinated individuals (HR 1.30; 95% CI, 1.14-1.49; p < 0.001). Increased risks were also observed for psoriatic arthritis and pustulosis palmaris et plantaris. These findings suggest a potential triggering role of infection in psoriasis pathogenesis and support the safety profile of vaccination. Further studies are needed to confirm causality and guide clinical decision-making.