Localised skin hyperpigmentation as a presenting symptom of vitamin B₁₂ deficiency complicating chronic atrophic gastritis

Vitamin B₁₂ deficiency is common in developing countries and should be suspected in patients with unexplained anaemia or neurological symptoms. Dermatological manifestations associated with this deficiency include skin hyper- or hypopigmentation, angular stomatitis and hair changes. We report a case of a 28-year-old man who presented to the Sultan Qaboos University Hospital in Muscat, Oman, in November 2013 with localised hyperpigmentation of the palmar and dorsal aspects of both hands of two months’ duration. Other symptoms included numbness of the hands, anorexia, weight loss, dizziness, fatigability and a sore mouth and tongue. There was no evidence of hypocortisolaemia and a literature search revealed a possible B₁₂ deficiency. The patient had low serum B₁₂ levels and megaloblastic anaemia. An intrinsic factor antibody test was negative. A gastric biopsy revealed chronic gastritis. After B₁₂ supplementation, the patient’s symptoms resolved. Family physicians should familiarise themselves with atypical presentations of B₁₂ deficiency. Many symptoms of this deficiency are reversible if detected and treated early.