My 12 year daughter is in good physical condition and has very good eating and hygiene routine. Still she has a peculair body odour. We can start noticing it, 3-4 hours after she had taken bath. It is quite mild though.
But after, say, an hour of tennis lessons or a session in gym, this body odour becomes quite strong. She also feels that otherwise, she sweats lesser then normal. Please advise what can be the probable causes and how can we try to help her overcome this problem; without her becoming too conscious of this state. Thanks.
Body odor is seen in poor hygiene (ruled out in your daughter's case) or medical conditions like thyroid disorder, carcinoid syndrome and taking drugs like antidepressant. Increased sweating due to any cause can also cause unpleasant body odour because microorganism in your body can break sweat into aromatic fatty acids which smell bad. All causes of hyperhydrosis like hyperthyroidism, diabetes, carcinoid syndromes infections etc should be eliminated. Even though she does not sweat much, these causes need to be eliminated.
Vinegar like smell in sweat is due to an acid called propionic acid. Since this acid is chemically similar to acetic acid in vinegar, the sweat smells of vinegar. This happens due to excess amino acids in sweat (which are breakdown products of protein), seen common with a high protein diet. Also if the diet is rich in cheese, then bacteria of staphylococcus type acts on the sweat and causes this smell of vinegar. Hence to avoid this smell you would need to carefully look at your daughter's diet and lower the protein and cheese content in it.
Since I cannot examine you and know other related conditions she may be having, nor is a detailed history possible on net, I have listed the various possibilities that should be looked into. Please consult your PCP or your daughter's pediatrician for primary examination followed by proper referral. Take care!