I would highly suggest you try the brand Seventh Generation Diapers and Wipes which are hypo-allergenic and they do not contain any chlorine. Chlorine is usually used to bleach regular diapers white. This is also an environmentally safe and natural brand. They make so many different safe household products that do not release poisonous chemicals...very ideal for babies. I am not certain of all of the places you will find Seventh Generation products, but WholeFoods definitely carries it. Call your nearest WholeFoods and ask if they carry Seventh Generation products to make sure.
Also, between diaper changes, let your son run around bare bottomed for a few minutes so that he gets aired out down there. It really helps with the healing process.
Another factor to be aware of...
like the previous mom whose daughter had a yeast infection, it may be a bacterial infection. In such a case, the creams will only work for a short time and then it will come back. You will need to cut back on feeding him anything with sugar or yeast. Sugar feeds bacteria. Fresh veggies juiced is very good for him. Try experimenting with different blends to fit his taste buds. If you do a lot of fruit, cut down and stick to citrus for a while. Generally moving to a low sugar diet would be very beneficial, overall.
I'd love to know your results when you try these things!