A corticosteroid injection (e.g., triamcinolone or methylprednisolone) is administered around the ECU tendon sheath, often with ultrasound guidance, to reduce inflammation and pain. Relief typically occurs within days to weeks, but the effects are temporary, lasting weeks to months. While injections can provide short-term relief, they come with risks, including tendon weakening or rupture with repeated use, temporary pain flare, and skin or tissue thinning at the injection site. Since steroids do not heal the tendon, physical therapy is essential for long-term recovery. Injections are recommended for persistent pain despite 4-6 weeks of conservative treatment, severe inflammation affecting function, or recurrent flare-ups hindering rehabilitation progress.