This Question Is For My Children. They Get These Bumps

This question is for my children. They get these bumps on their backs, buttocks, and legs. My daughter gets them on her vaginal area also. These bumps fester and also leave holes and bad scars. My daughter was tested and her doctor told her he had never seen anything like it. In other words he did not know how to treat them much less have a solution for preventing them. I believe it has to be a form of staff infection. They both have taken antibiotics (strong) but with no positive outcome.
My hope is that someone as yourself may have heard of something like this or have a suggestion for them to try. I would like to think that a simple bump could be curred. I would like to believe this is something that is simple but they have lived with these bumps for years.
I know this really sounds simple but it is causing my children problems.