There are a number of metabolic disorders that may cause a fruity smell on the breath, a sweet smell on the skin or a sweet smell in the urine. These disorders are treatable, though some may be signs of deeper underlying problems.
Maple syrup urine disease (MSUD) is a metabolic disorder that is genetically inherited. It causes an inability for the body to break down the amino acids valine, leucine and isoleucine. This causes a build-up of harmful levels of these substances in the blood. Symptoms include loss of appetite, lethargy, vomiting, urine that smells like maple syrup, seizures and coma. Treatment involves a diet free of protein, intravenous intake of sugars, fats and fluids. Hemodialysis may also be used as a means of reducing the level of amino acids.
Lactic acidosis is cause when the level of lactic acid in the blood stream increases faster than it can be removed. Symptoms include nausea and weakness and a sweet, fruity smell on the breath or skin. Treatment is focused on amending the underlying causes of the disorder. Blood tests are necessary to check electrolyte levels. The most common cause of lactic acidosis is intense and prolonged exercise, this is due to the fact that lactic acid levels increase as oxygen levels decrease. It may also be caused by AIDS, cancer, respiratory failure, kidney failure and sepsis.
Diabetic ketoacidosis is a complication of diabetes. It occurs when there is insufficient sugar in the body to be used as a source of fuel and fat is used instead. Ketones–byproducts of the breakdown of fat–begin to build-up in the body with negative effects. Symptoms include weakness, frequent thirst, frequent urination, fatigue, loss of breath, nausea, vomiting and a sweet or fruity smell on the breath or skin. Treatment involves increasing the dosage of insulin and replacing lost fluids.