I don't think you have an STD. First of all, yeast is not usually transmitted. People get it by themselves, presumably from the GI tract, plus sweating, etc. Second, your rash does not sound like any STD I know of. What I think you have is just persistent redness left over from inflammation all those creams got rid of. As you say, this "does get inflamed particularly after a hot shower," because heat reddens the skin. It means nothing.
I advise you to apply nothing medical to the skin--just moisturize, and wait things out, because the redness will go away. I also advise you to simplify your sexual situation, since your recent changes are causing significant anxiety.
If your rash changes or worsens instead of gradually fading, you should consult one of the doctors you already saw.
Best.
Dr. Rockoff
What you describe I have been plaged with for about 7 years, I am currently 53 years old. It seems to get worse each year. I have not been able to get any kind of straight answer from my Dr. His last explaination was it must be some kind of fungus. Based on that statement, I stopped using prescribed meds (which did not seem to really do much and for the last 2 weeks I have been treating it as "jock Itch" I have been applying "Cruex cream" which is an over-the counter cream antifungal clotrimazole. It seems to have placed this annoying rash in "resession". the redness is all gone- all that is currently left is the slight discoloration showing how far the "fungus" had spread. I have been getting concerned as my rash had spread to my bullocks and starting down my thighs. I am keeping my fingers crossed- Hopefully the above treatment will reverse this before it becomes something not covered by cloths (i imagine you know what I mean).
Of note: Salt water(sea water) is excellent but after a few days the rash comes back. If anyone has any successes at removing or curing the exact rash Eddie describes please post to us.