Hi Welcome to the HCM I have gone through your question and understand your concerns. It seems that your child may be suffering from an inborn error of metabolism known as Maple syrup urine disease. The intermittent variant of this disease menifests at the times of illness leading to accumulation of branched chain amino acids in the body. These acids give typical odour of maple syrup in urine and body odour. You may take him for plasma amino acids analysis for diagnosis and management accordingly. Hopefully this will help you. I would be happy to help you in any further questions. Take care