is this surf rash? what can i do

Hi there
for some time now i have developed some sort of rash under both my knees and on the inside of my legs, i have bought 6 different type of boardies, the latest being $155 billabong pair to help stop the rash with no success, i have been to 2 different doctors both of them saying that this is a fungal infection and they give me cream, then it goes and then comes back later.
Does this sound familiar to anyone? i cant seem to control it, and i surf every day which doesnt help, but i cant work out is it a rash from my boardies? or a fungal inefection from warm water or both?
its been a couple of years i dont seem to get it in a wetsuit through winter
any advice would be appreciated, oh and its incredibly itchy!! especially at night
cheers
for some time now i have developed some sort of rash under both my knees and on the inside of my legs, i have bought 6 different type of boardies, the latest being $155 billabong pair to help stop the rash with no success, i have been to 2 different doctors both of them saying that this is a fungal infection and they give me cream, then it goes and then comes back later.
Does this sound familiar to anyone? i cant seem to control it, and i surf every day which doesnt help, but i cant work out is it a rash from my boardies? or a fungal inefection from warm water or both?
its been a couple of years i dont seem to get it in a wetsuit through winter
any advice would be appreciated, oh and its incredibly itchy!! especially at night
cheers