Why does hair sometimes grow back white after alopecia areata? Expand When hair regrows after alopecia areata, it may appear white due to a lack of pigment-producing cells called ‘melanocytes’. In alopecia areata, the immune system mistakenly attacks hair follicles, causing hair loss. When hair begins to regrow, the melanocytes may not fully function, resulting in white/colourless hair. It is understood that although melanocytes are present in the regrowing white hair follicle, the cells that will form the hair are initially unable to take up pigment from the melanocytes. Over time, the pigmentation may return to normal but for some people the hair may remain white. Unfortunately, we do not understand why some people regain hair colour and others do not.