A toddler with transient synovitis and COVID-19 infection.

Transient synovitis of the hip is a common medical emergency in children. Although reactive arthritis in adults may occur 1-4 weeks after COVID-19 infection or post-vaccination, few reports of transient synovitis in children associated with acute COVID-19 infection have been made. Transient synovitis of the hip occurs most frequently in children 3-8 years of age with a recent upper respiratory infection, bacterial infection, or trauma.