My understanding has always been that the increased skin pigmentation can indicate that not enough cortisol is beeing produced (or replaced with meds). I believe that it is melanin that is being over-produced along with the progesterone. Maybe someone else reading this can correct or confirm that. I know I have something in my collection of articles somewhere. The process of the skin darkening occurs over an extended period of time. My daughter (now 15) was diagnosed at 2 and 1/2 yrs and had the most incredible tan complexion even where she shouldn't have been tanned. Once on meds, her complexion lightened considerably. Even when she was born, she looked somewhat tanned.... at first, we just thought it was her normal skin colouring.