Acrodermatitis Dysmetabolica Secondary to Isoleucine Deficiency in Infant With Maple Syrup Urine Disease

The document reports a case of a 2-month-old boy with maple syrup urine disease (MSUD) who developed acrodermatitis dysmetabolica (AD) due to isoleucine deficiency. The infant, diagnosed with MSUD at 5 days old, was treated with a branched-chain amino acid (BCAA) restricted diet, BCAAs formula, and thiamine supplementation. He presented with diarrhea, skin eruptions, and hair loss. Laboratory tests showed low isoleucine and high leucine levels. Treatment with isoleucine supplementation and leucine restriction, along with topical mometasone ointment, led to complete resolution of the skin eruption within 4 weeks, coinciding with the normalization of BCAA levels. This case emphasizes the risks associated with BCAA diet restriction in treating MSUD and the importance of closely monitoring amino acid levels during periods of growth to prevent AD.