To the Editor.—
Maple syrup urine disease (MSUD) is caused by a block in the breakdown of three branched-chain amino acids (BCAAs): leucine, isoleucine, and valine.1 We describe an infant with classic MSUD where inadequate dietary intake of BCAAs2 resulted in an exfoliative dermatitis. When the BCAA intake was increased, the eruption resolved.
Report of a Case.—
A 4.5-month-old boy presented at another hospital with hypoglycemia, acidosis, and seizures requiring intubation and phenobarbital therapy. Physical examination was unremarkable except for mild hepatomegaly and marked growth retardation. By day 3 of hospitalization, he was extubated. His unusual urine odor led to an evaluation for MSUD, and the infant received a BCAA-deficient diet. Seven days before he was transferred to our hospital, gradually worsening skin changes developed.Amino acid levels drawn prior to his transfer revealed the following elevated values: valine, 595.5 μmol/L (normal, 145 to 316 μmol/ L); leucine,
Northrup H, Sigman ES, Hebert AA. Exfoliative Erythroderma Resulting From Inadequate Intake of Branched-Chain Amino Acids in Infants With Maple Syrup Urine Disease. Arch Dermatol. 1993;129(3):384-385. doi:10.1001/archderm.1993.01680240130027