Flexor Tendon Sheath Infection
A potentially serious infection around a finger flexor tendon that can progress quickly and threaten function.
Why it matters
The flexor tendon runs through a closed synovial sheath. Bacteria introduced by a puncture, cut or spread from nearby infection can multiply within this confined space.
Typical features
Classically the finger is diffusely swollen, held partly flexed, tender along the flexor sheath and very painful when passively straightened. Not every patient has every sign.
Diagnosis
Diagnosis is primarily clinical. Blood tests and imaging may support assessment, but they should not delay urgent treatment when the clinical picture is concerning.
Treatment
Early infection may sometimes be treated with close specialist observation and intravenous antibiotics, but many cases require urgent surgical irrigation and debridement.
Why delay is risky
Rising pressure, bacterial toxins and inflammation can damage tendon gliding surfaces and surrounding tissues, leading to stiffness, tendon necrosis or spread of infection.
Recovery
After infection control, wound care and hand therapy are often needed to restore movement and limit adhesions.
Rapid finger swelling, severe tenderness along the palm side of the finger, fever, or pain when someone gently straightens the finger should be assessed urgently.