Is there a dye for revealing athlete's foot?

There’s an over-the-counter product known as disclosing tablets that’s intended to help people improve their toothbrushing. It is basically a dye that you apply to you teeth after brushing which conspicuously stains any remaining plaque. You can then make a note of the areas that you missed and modify your brushing technique.

Does there exist a similar product that can be applied to the skin and which makes visible the fungus that causes athlete’s foot? I think this would help make sure that whatever topical medication is being used to treat it is being applied in all the right places, and could also help track the progress of the treatment.

It’s plausible you could make one, but unlike your teeth, which get permanent damage if you have bad brushing habits, your feet will just get itchy and remind you to resume treatment. Athlete’s foot also creates its own markers, itchy and flaky skin.

I’d be highly surprised if the product currently exists.

Some types of fungal infections can be seen with a UV light. Not all fungi are fluorescent, so you wouldn’t necessarily be able to spot all types of infections that way.

Or there was, or there may be again. When I tried Amazon and all local suppliers 2 or 3 years ago, there was no such thing.

According to Wikipedia, fungi in the genera Trichophyton, Epidermophyton, and Microsporum are common causes of athlete’s foot. Do you know whether these fungi are visible under UV light?

There seem to be plenty available on Amazon, mostly from the brand PlaqSearch. Perhaps even more would be available from an online pharmacy.

No, I don’t know if those specific ones are. Maybe someone else does. I had wondered about this in the past for the same reason as you. I didn’t want to cover my whole foot in treatment if I didn’t have to. But then when I saw that only some of the possible strains would be visible, I didn’t investigate any further.

Yeah, this was pretty much my motivation for asking here in the first place. I recently finished a three-week course of treatment using a relatively expensive ointment and so didn’t want to use it on areas that weren’t infected. The infection returned after a few weeks, so now I’m wondering whether this is because I picked it up from an external surface that I didn’t wash thoroughly enough (such as a floor or sock) or because it was still lurking on my foot, asymptomatically, on some area that I didn’t medicate. I figured I could confirm or eliminate this latter possibility if I had some sort of “disclosing tablet” for my feet.

I don’t think you ever get rid of it. The next thing to do is switch to a different medication. There are 4 or 5 common ingredients. Once I found the one that worked for me (after years of switching as I wasn’t paying attention to the active ingredient) everything was fine for a year or so. That was over 15 years ago. It comes back every few years but responds very quickly, often in a day or two.

They certainly would be visible under UV if you squirted them with fluorescent antibodies to the fungal “skin” protein.
Some lab rat has probably made the stuff, but I doubt it’s commercially available.

Qadgop? Jackmanii? Where are you?

This is pretty much it. One can keep it at bay, but it does not go away.

Some Microsporum certainly are:
Fluorescent Pigment of Microsporum | Nature

That’s interesting. Like I said, 2 or 3 years ago.
Also, I notice that all are two-color dyes: red and blue. How long has that been the case?