If this has been going on for 15 years, I think its more than time to see a good dermatologist. Its a possibility, but unlikely, that you could have a fungal infection this long, but I'd wonder about allergic reactions, eczema, etc. We have a really good dermatology forum here that you should check out -
http://www.medhelp.org/forums/show/65
If you aren't comfortable using the new cream, then don't.
Happy birthday.