A 67-year-old, otherwise healthy man presented with spontaneous repigmentation of his gray hair (Figure).
The reports on this phenomenon are scant in the literature,1- 4 though it may not be as rare as assumed. In fact, it is not too uncommon to see spontaneous repigmentation along the same individual hair shaft in early canities (loss of hair pigment resulting in graying of the hair). Moreover, melanocytes taken from white hair follicles can be induced to pigment in vitro.5 The most dramatic cases of return of normal hair color from white are probably examples of pigmented hair re-growth following alopecia areata or the Marie Antoinette syndrome.6 Repigmentation of hair observed in Addison disease has been attributed to a mechanism similar to that seen in alopecia areata, in view of the known association between these 2 presumably autoimmune diseases. On the other hand, it may also be explained through the effect of elevated levels of melanocyte-stimulating hormone, which applies to pigmentation of skin and hair in Nelson syndrome and ectopic adrenocorticotropic hormone syndrome as well. Since the stimulation of pigment formation may also affect the hair, a conspicuous darkening of the hair should suggest the possibility of these disorders. In our patient, however, careful evaluation for underlying endocrinologic disorders or neoplastic disease did not reveal any abnormalities.
Navarini AA, Trüeb RM. Reversal of Canities. Arch Dermatol. 2010;146(1):103-104. doi:10.1001/archdermatol.2009.337