Reversible Hyperpigmentation of Skin and Nails With White Hair Due to Vitamin B12 Deficiency
 August 1986   
in “
 Archives of Dermatology 
”
 
      TLDR  Vitamin B12 deficiency can cause skin and hair color changes, which can be reversed with treatment.   
  A case study from 1986 reported on a patient with reversible generalized hyperpigmentation of the skin and nails, along with premature gray hair, caused by vitamin B12 deficiency due to pernicious anemia. The patient's skin and hair pigmentation returned to normal following treatment with intramuscular cyanocobalamin.