Technically speaking it is a keratopathy. It is a physiological, chemical and morphological alteration related to the path to the outside of epithelial cells.
The first thing to think about is that calluses appear because of the bones. If someone suffers from any alteration with their metatarsalians during walking, this could turn into plantar calluses. If we cannot avoid this issue when doing a conservative treatment, then this metatarsal must be targeted, since it is the cause of callus production.
As with all types of calluses, at the foot, the main problem lies within the bone. That is why it always goes to the same place, which means that if we want to eliminate the callus definitively, we must target the bone that causes it.
Skin hardnesses on the foot -or calluses, as they are more popularly known- always appear in the foot areas where there is more friction or pressure (due to tight shoes, for example).
That is why, behind a callus, we have a problem in the bone, which causes it to always appear in the same place until the professional acts to find a solution.
The most common regions where calluses appear change depending on the type of foot, but under the metatarsal and the toes it is where they appear more frequently.
Of course they can, there are more difficult cases to treat depending on the areas of the foot, but they are solved when we perform either the preventive treatment (chiropody, discharge, orthopedic treatment, silicone ortesis) or the definitive (surgical).
The reason why this confusion exists is because they are very similar. During palpation both are annoying, but the wart causes pain when you get a pinch on it, whereas the callus does not.
This is a simple and practical test to perform, but in any case you need to go to the podiatrist since it is the specialist who can solve the problem.