D.S.
Hi M., I have 6 children and yes I had to deal with this with my 3rd child. She had the same problem, and so when I asked my doctor what to do. It was pretty simple and it worked; everytime she takes a bath, put baking soda in her water and let her soak in it. Another thing you could do, is once she's done with her bath, also put baking soda under her armpit. These methods worked for me. My daughter is now 11 and she's okay. I never had to consult a doctor again, nor did I have to use deoderant at an early age.
I hope this helps.
D. S