Can the colour of skin change with age
Vitiligo is a loss of skin pigmentation that causes patches of lighter skin as the immune system attacks melanocytes. It can eventually progress to cover the entire body. 

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Ongenae, K., Van Geel, N. and Naeyaert, J.-M. (2003), Evidence for an Autoimmune Pathogenesis of Vitiligo. Pigment Cell Research, 16: 90–100. doi: 10.1034/j.1600-0749.2003.00023.x