Tendon sheath inflammation is primarily due to long-term engagement in certain frequent activities, causing inflammatory damage to the tendons and tendon sheaths. This results in symptoms such as swelling and limited mobility. It is difficult to cure without treatment intervention. For the treatment of tendon sheath inflammation, it is firstly important to rest and stop the frequent activity. Medications such as non-steroidal anti-inflammatory analgesics can also be used. Additionally, treatments such as applying heat, physiotherapy, and local encapsulation can be employed. Through these treatments, some patients can recover effectively. When there is a significant impact on life due to functional impairment, surgical treatment may also be considered. Post-surgery, it is important to start functional exercises early to prevent adhesion. (Medication should be used under the guidance of a physician.)