irratating skin lesions similar to megellons

Hello my mother has a skin thing going on. It first starts off like a pimply rash, mainly around her mouth, eyes, neck,face, back and extremities. They are itchy and it takes a while for the pimply area to heal. Sometimes there are black specks that are contained in the pimple. Dr.s do not know what this is. Sometime she can brush or wipe the black specks off. The black specks sometimes look like a very short piece of thread. She is fatigued and some memory loss. These are pretty constant and sometimes there are more flare ups. Thank you, Tweet