The causes of bone protrusion next to the big toe of the foot include bunion, bunionitis, gout and so on. 1. Bunion: The bunion is obviously skewed outward, leading to degeneration and hyperplasia of the toe-metatarsal joints on the inside of the bunion, which results in the thickening of the joint capsule. This causes the bone next to the big toe to protrude. 2. Bunion: common in women who often wear high heels. As the front end of high heels is narrower, the palm of the foot impacts forward during walking, thus squeezing the bunion and causing aseptic inflammatory reaction of the bunion, which leads to bunionitis. The inner metatarsophalangeal joint of the big toe is obviously raised. 3. Gout: As a result of long-term consumption of a high-purine diet, a large amount of uric acid is produced in the body, which increases its level in the blood, leading to the deposition of urate crystals in the joints and other tissues and the formation of gout stones. Pain in the first metatarsophalangeal joint occurs, which manifests as a protruding bone next to the big toe of the foot. There may be other causes for the bone protruding next to the big toe of the foot. It is recommended to avoid strenuous activities on the big toe of the foot, and loose and comfortable shoes should be worn, avoiding high-heeled shoes, to minimize the local irritation. If the symptoms are severe, it is recommended to go to the hospital for consultation.