Multiple carboxylase deficiency (MCD) is an autosomal recessive metabolic disease due to holocarboxylase (HCS) deficiency or biotinidase (BTD) deficiency, characterized by unrelenting dermatogical abnormalities and severe keton acidosis in acute periods. Here, the authors report the first case with MCD in Vietnam. Case report: A 11 months old girl was admitted in emergency department with severe metabolic acidotic coma and unrelenting eczema since 1 months of age. Her older brother and twin siter died on the sam condition at 11 months of age. Her condition was dramatic improvement with biotin treatment (10 mg/ day): releasing keton acidosis, considerable decreased eczema after one day, complete eczema disappearance after two weeks. Now, she was 7.5 years old and normal development. Conclusion: Unrelenting eczema may be symptom of MCD and treatable disease.