Lateral bunion pain may be caused by physiological factors such as long-term shoe inappropriateness, or pathologic factors such as trauma, fasciitis, bunion deformity and arthritis. 1. Physiological factors: Mostly due to long-term shoe inappropriateness, over-exertion and other physiological factors, patients may experience pain on the lateral side of the big toe after activities. 2. Trauma: Local bone and soft tissue injuries caused by excessive exercise may result in lateral bunion pain, swelling, and restriction of activities. 3. Fasciitis: Aseptic inflammation of the local fascia due to long-term localized extrusion, friction, and strain injury can cause lateral bunion pain. 4. Bunion deformity: The pain on the outside of the big toe can be caused by bunion deformity, which is caused by the thumb squeezing the second toe or joint deformity when walking or moving for a long period of time. 5. Arthritis: It is common in gouty arthritis caused by blood uric acid deposition, rheumatoid arthritis caused by inflammation of the joints, which can appear on the lateral side of the big toe pain. There may also be other causes of pain on the outside of the toe, so it is recommended to go to the hospital in time to improve the examination to clarify the cause of the disease, and then give targeted treatment or therapy.