There are many reasons for the swelling of a finger, the common causes are trauma and secondary infection, but also may be related to certain diseases, need to be analyzed from a number of aspects, to clarify the cause of the cause of treatment. First, external stimuli: 1, trauma: life is not careful, the finger accidentally hit in other places, will lead to swelling of the finger; 2, infection: the patient’s finger accidentally cut, did not timely treatment, resulting in infection of the finger, there will also be a finger swelling; 3, allergy: finger contact with allergic substances, which can lead to local skin allergies, swelling. Second, disease factors: 1, local inflammation: common tenosynovitis and rheumatoid arthritis. If you suffer from tenosynovitis, inflammatory factors gather, easy to lead to a single finger swelling. The latter often occurs in elderly patients, the onset of the finger will be deformed and swollen; 2, hyperuricemia: high uric acid leads to gout stone crystallization in the finger joints, which will cause gouty arthritis, resulting in finger swelling. Therefore, the cause of swelling in a single finger needs to be analyzed together with various factors, such as the patient’s medical history, history of trauma and so on. Only by understanding the relevant circumstances can the cause of finger swelling be better analyzed and treated.