Dietary vitamin B(12) (vitB(12)) deficiency, although common in the elderly, is rare in childhood. We report on an exclusively breastfed 8-month-old infant, presenting with persistent refusal of solid foods. Three months later, developmental regression and failure to thrive led to the diagnosis of vitB(12) deficiency, as a consequence of a subclinical pernicious anaemia with vitB(12) deficiency in the mother. Treating the infant with parenteral vitB(12) induced prompt recovery including acceptance of weaning food.
Conclusion: This case illustrates refusal of complementary foods as a presenting symptom of vitB(12) deficiency in a breastfed infant. Symptoms, diagnostic tests and treatment of vitamin B(12) deficiency are reviewed. Early diagnosis and treatment are important to prevent irreversible neurological damage.