In a dorsal bunion the big toe is usually turned towards the other toes and you often see red calloused skin alongside the inside of the big toe and a bump. Based on your description your wife could have a dorsal bunion but only a doctor can tell - and they can usually do it just by looking at it.
The next question is what to do about it. Dorsal bunions can be caused by narrow toed shoes - if your wife is wearing shoes like that a wider shoe could be very helpful in bringing her big toe back into alignment. She might also try felt pads around the bunion to protect it.
Its good to take care of this early. A trip to your doctor or podiatrist should be really helpful. Good luck!