A bunion occurs when the metatarsophalangeal (MTP) joint at the bottom of your big toe shifts out of place. This creates a prominent bump on the side of your big toe. While the bony bump looks like the main problem, bunions actually start much deeper in the foot. They begin when an unstable joint in the middle part of your foot shifts, causing a gradual chain reaction that eventually leads to the MTP joint shifting out of place.
The root cause of bunions is usually genetics. You may have a propensity for bunions due to the foot structure you inherited from your parents. Changes in weight, pregnancy, injury, and other factors can also shift the alignment of bones in the feet, potentially leading to bunions. Shoes don’t directly cause bunions; however, if you’re prone to bunions, wearing high heels can certainly cause them to develop faster or worsen them.