Diffuse melanonychia as a clue to vitamin B12 deficiency.

The article presents a case study of a 16-year-old Indian girl who has developed lymphadenopathy nor sternal tenderness and mild hepatosplenomegaly associated with severe pallor, bluish nail discolouration and knuckle pigmentation in both hands and feet. The diagnosis was emphasized. And discusses nail apparatus which produces nail fold, nail matrix and nail bed.