Reversible hyperpigmentation of vitamin B12 deficiency

A woman† in her eighties was referred to the department of Dermatology of Sri Manakula Vinayagar Medical College and Hospital, Puducherry, India, in April 2019, for the evaluation of hyperpigmentation. She had bilateral pallor and blotchy greyish-black hyperpigmentation over palms and soles (Figs 1, 4A), proximal and lateral nail folds, dorsal aspect of the distal phalanx and the proximal interphalangeal joints. There was diffuse brownish discolouration of the nail and longitudinal melanonychia of the left middle finger nail (Fig. 2A). She was an ovo-lacto vegetarian. Investigations revealed pancytopenia (haemoglobin - 6.2 g%, WBCs - 1400/mm³ and platelets - 34,000/mm³) and a mean corpuscular volume of 104 fl (normal range 83-101 fl). A peripheral smear revealed dimorphic anaemia, leucopoenia and thrombocytopenia with a few giant forms. The serum vitamin B12 level was less than 83 pg/ml (normal range 187-883 pg/ml). She received intravenous methylcobalamin (1000 mg daily) for ten days. On the ninth day, there was rapid improvement in the haematological parameters (haemoglobin - 10.2 g%, WBCs - 6100/mm³, platelets - 245,000/mm³) and a mild reduction in hyperpigmentation. She was followed up with weekly intramuscular vitamin B12 injections, with iron and oral multivitamin supplements. There was a significant improvement in the cutaneous pigmentation (Figs 3 and 4B) at five weeks and reversal of the longitudinal melanonychia at 12 wk (Fig. 2B).

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Fig. 1

Blotchy greyish-black pigmentation over palms.

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Fig. 2

(A) Diffuse hyperpigmentation and longitudinal melanonychia. (B) Reduction in hyperpigmentation and reversal of longitudinal melanocychia at 12 weeks.

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Fig. 3

Reduction in pigmentation after five weeks.

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Fig. 4

(A) Blotchy greyish-black hyperpigmentation over soles. (B) Reduction in hyperpigmentation after five weeks.

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