There isn’t one single cause of metatarsalgia. It’s a condition that typically develops due to multiple factors. Sometimes it’s biomechanical issues, such as a high arch, flatfoot, or development of a bunion. Small changes in your gait (how you walk) can alter shock absorption and general propulsion, putting more pressure on the metatarsals.
In some cases, one of the metatarsals is closer to the ground than the others. Consequently, it absorbs more forces and can become irritated and inflamed. This is considered a static form of metatarsalgia rather than a propulsive form, one related to walking or running.
Chronic illnesses like rheumatoid arthritis, psoriasis, and gout can also contribute to the development of metatarsalgia. Osteoarthritis, for example, can affect a joint near the metatarsals putting more pressure and weight on the metatarsal heads.
Metatarsalgia can also develop after an injury. Overcompensating after a knee, ankle, or unrelated foot injury can change how you distribute weight on the metatarsals, increasing forces and pressure.