There are several possible causes of bunion pain and swelling: first, gout, when gout involves the toe, often the first symptom is bunion pain and swelling, which can be accompanied by redness and swelling of the skin, increased skin temperature, and the formation of gout stones, to be diagnosed and treated by blood tests and foot x-ray. Second, tumors, when there are tumors in the bones and soft tissues of the big toe, there can also be pain and swelling, and early nuclear magnetic examination, as well as physical examination and x-ray examination should be performed for diagnosis. Third, local infection, when there is a bacterial infection or tuberculosis infection, there can also be pain and swelling in the bones and soft tissues, and in severe cases, there can be sinus tract formation, and blood tests, as well as X-rays and MRI of the feet, should be performed for early diagnosis.