I don't know anything about the fingernail splitting thing however I do know about athletes foot.

First of all, did you have it diagnosed as althetes foot? There are some other things like eczema and whatnot that mimic athletes foot and would explain why your creams aren't working.

If it has been diagnosed as athletes foot, there are several things you can do that will help. Although some people are just more prone than others to get it.

1) Don't wear the same pair of shoes every day. Have 2 pairs of work/school shoes that you can alternate.

2) The pair of shoes you're not wearing at the time, pull the tounge up and open them as much as possible for air flow. Set them near your heat register or better yet on a sunny day hang them out on the clothesline.

3) Change your sox at least twice a day. Using plain white thick cotton sox is best since you can bleach them easily when you wash them.

4) Keep using your creams, but always wash your feet before putting it on and make sure to dry your feet and between toes WELL, put a hair dryer on them if necessary.

5) Wash your shoes once a week in the washing machine, unless your dryer has one of those shoe shelves, stuff your shoes with newspaper and set near the heat register, or hang on clothesline. Make sure they are completely dry before wearing again.

6) Chose shoes that allow your feet to breath, not like a solid type dress shoe if you can help it.

7) Always wash your feet and between toes well when you shower, and dry your feet and between toes completely before even attempting to put on your sox. Use a hair dryer on your feet if necessary.

8) Keep a pair of sandles for wearing to a public swim area or anywhere you would normaly walk barefoot.

9) If your bathroom has a rug, wash it frequently, if you have linolium/tile mop it with bleach frequently.

Hope that helps. It's always worked for me and my family.