What Causes Slightly Raised Blotches Around The Areola?

Since November I have developed cluster-like, slighly raised, non-itchy, non-scaling, blotches circling around nearly 3/4's of my areola. They areas appear to be thicker than my other breast as they are darker in color than my areola but still are flesh colored. This is only on one breast. Do you have any idea what it could be? Creams that I have tried at home do not get rid of it and it does no spread to other areas of my body.