Hello, Well, it will depend on the duration from which they are there. If they are of acute onset without any history of trauma then it may be a cause of concern. But if it is there from a longer period of time without any associated complications or symptoms then it is less likely to be a cause of concern. In that case, it could be nevus but it has changed colour to purple from black it again is the cause of concern. If it is acute then without trauma it most probably can be ecchymosis due to low platelet count which can have a variety of causes. At last, I would like u to visit a clinic for a checkup because matters most and one shouldn t take any chances with that (a better history would have helped). Hope I have answered your query. Let me know if I can assist you further. Take care Regards, Dr Mubashir, General & Family Physician