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Generalized Hyperpigmentation of the Skin due to Vitamin B12 Deficiency
Author(s) -
Mori Katsunori,
Ando Iwao,
Kukita Atsushi
Publication year - 2001
Publication title -
the journal of dermatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 65
eISSN - 1346-8138
pISSN - 0385-2407
DOI - 10.1111/j.1346-8138.2001.tb00134.x
Subject(s) - hyperpigmentation , melanosome , dermatology , malabsorption , depigmentation , melanin , medicine , vitamin b12 , megaloblastic anemia , anemia , gastroenterology , endocrinology , chemistry , biochemistry
A 49‐year‐old man presented with neurosis, hyperpigmentation of the skin, and depigmentation of the hair. On examination, hyperpigmentation was observed on the oral mucosa and the skin of the forearms, elbows, palmar creases and periunguinal area, knees, and feet. He had megaloblastic anemia with a low serum level of vitamin B12 due to malabsorption resulting from a gastrectomy 10 years previously. His hyperpigmentation was resolved with vitamin B12 supplementation. Histology showed an increase of melanin in the basal layer. In electron microscopic study, many melanosomes were observed in melanocytes and surrounding keratinocytes. We consider that the dominant mechanism of hyperpigmentation due to vitamin B12 deficiency is not a defect in melanin transport but is rather an increase in melanin synthesis.