loss of pigment which may be followed by a lengthy period when the skin colour does not change. It can occur on any part of the body. Hence to confirm the diagnosis you need to get it evaluated and get a biopsy skin done.
It is very difficult to precisely confirm a diagnosis without examination and investigations and the answer is based on the medical information provided. For exact diagnosis, you are requested to consult your doctor. I sincerely hope that helps. Take care and please do keep me posted on how you are doing.