I too have had an ongoing battle with what all docs believe to be a fungal infection on my left foot, but not my right foot!!! How goofy is that?!!?
Has the docs stumped too!! LOL!
I believe it to be a form of tick-borne skin infection, like the EM rash is the skin infection stage of Lyme. There are sooo many pics of the different rashes that the different TBI's can cause, that it's hard to narrow it down. Mine looks like either a rash from a strain of Bartonella, or a strain of RMSF. I'm leaning towards RMSF though, as those pics look a little closer to what I see on my foot.
I will be interested in finding out if someone else either has this or has a possible answer for this!!!