There are many reasons for the swelling of a finger, and the common causes are trauma and secondary infection, which may also be related to certain diseases, and need to be analyzed from several aspects and treated for the cause after clarifying the cause. I. External stimuli: 1. trauma: inattention in life and inadvertent bumping of the finger in other places can lead to swelling of the finger; 2. infection: the patient’s finger is inadvertently cut and not treated in time, leading to infection of the finger, which can also lead to swelling of a finger; 3. allergy: the finger is exposed to allergic substances, which can lead to local skin allergy and swelling. Second, disease factors: 1, local inflammation: common tendovaginitis and rheumatoid arthritis. If you suffer from tendovaginitis, inflammatory factors gather, which can easily lead to swelling of individual fingers. The latter often occurs in elderly patients, and the fingers will be deformed and swollen at the onset; 2. Hyperuricemia: high uric acid causes gout stones to crystallize in the finger joints, which can cause gouty arthritis and lead to swelling of the fingers. Therefore, the causes of swelling in individual fingers need to be analyzed together with various factors, such as the patient’s medical history and history of trauma. Only by understanding the relevant circumstances can the cause of finger swelling be better analyzed and treated.