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Severe vitamin B12 deficiency can cause skin and tongue hyperpigmentation. This easily treatable condition improved significantly with vitamin B12 therapy, highlighting the importance of recognizing atypical presentations.

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Area of Science:

  • Internal Medicine
  • Hematology
  • Dermatology

Background:

  • Vitamin B12 deficiency is a common condition encountered in general practice.
  • Atypical presentations can pose diagnostic challenges.

Observation:

  • A 64-year-old man presented with chronic, treatment-resistant hyperpigmentation of the skin and tongue.
  • Clinical examination revealed anemia, skin/mucosal hyperpigmentation, Romberg sign, and hyperreflexia.
  • Laboratory tests excluded adrenal insufficiency and indicated macrocytosis with hypersegmented neutrophils, consistent with severe vitamin B12 deficiency.

Findings:

  • Parenteral vitamin B12 treatment led to significant improvement in both hyperpigmentation and anemia within 3 months.
  • The proposed mechanism for hyperpigmentation involves increased melanin deposition in the basal epidermis due to vitamin B12 deficiency.

Implications:

  • Highlights vitamin B12 deficiency as a potential cause of unexplained skin and mucosal hyperpigmentation.
  • Emphasizes the importance of considering and investigating vitamin B12 deficiency in patients with similar atypical presentations.
  • Underscores the treatability of this condition with prompt diagnosis and intervention.