Reversible Hyperpigmentation in Vitamin B12 Deficiency: an Addisonian Mimic in Clinical Practice

Vitamin B12 deficiency may present with gastrointestinal, haematologic, dermatologic and neuropsychiatric signs and symptoms. Skin hyperpigmentation is a dermatologic manifestation which may mimic the features seen in Addison´s disease. We report a case of a 33-year-old non-vegan man who presented with progressive darkening of his palms, knuckles and feet which was associated with anaemia. Low serum vitamin B12 levels coupled with characteristic morphology of peripheral blood smear and bone marrow aspirate were identified. An extensive work up to establish the cause of Vitamin B12 deficiency revealed Helicobacter pyloriassociated gastritis as the likely aetiology. The patient had significant reversibility of hyperpigmentation and normalisation of the haematological indices following parenteral vitamin B12 supplementation. This case highlights the need for a high index of suspicion when clinicians are faced with a case of hyperpigmentation, so that the appropriate treatment can be promptly instituted and the late irreversible complications of vitamin B12 deficiency prevented.