Solid food refusal as the presenting sign of vitamin B₁₂ deficiency in a breastfed infant

Dietary vitamin B₁₂ (vitB₁₂) 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 vitB₁₂ deficiency, as a consequence of a subclinical pernicious anaemia with vitB₁₂ deficiency in the mother. Treating the infant with parenteral vitB₁₂ induced prompt recovery including acceptance of weaning food. Conclusion: This case illustrates refusal of complementary foods as a presenting symptom of vitB₁₂ deficiency in a breastfed infant. Symptoms, diagnostic tests and treatment of vitamin B₁₂ deficiency are reviewed. Early diagnosis and treatment are important to prevent irreversible neurological damage.