First off? Treat your feet as if you’ve got type 1 Diabetes..

then read this site: url-http://telemedicine.org/stamford.htm-url
Go t o the left margin to the tab ‘Diabetes in Skin Disease’ and read the intro and other stuff…
Fungus? Possibly, yes. BUT, hygiene is also a factor. Don’t know about you, but my feet [which had had ‘hyperhydrosis’ prior to..?] stopped sweating COMPLETELY for over a year! Until I started IVIG..then little spots would sweat, now it’s not ‘normal’ but at least I CAN SWEAT!
Get and use a mirror for diabetes and LOOK at your feet, as you don’t feel them! Slather with lotions such as Ammonium Lactate [SP?] and other suitable moistureizers. Then go to a dermatologist and get tested for possible other issues…such as fungus or worse. They have several topical ointments or salves that work great for avoiding possible complications.
Dermatologists are like neuros in a way? THEY ARE HARD [the good ones at least] to get appointments with WHEN YOU NEED THEM! So, go get established, examined then work to prevent any additional skin problems before they happen. Being an established patient is useful too, IF you get IVIG, and get a reaction! Trust me on this one- two topicals and no problem after that! IVIG ‘rashes’ feels like poison ivy all over again!
As for toes? This often happens as we ‘age’. Hate to say it? But my own neuropathy problems were made worse by ingrown big toes [which started about 2 years before neuro stuff]. At first, I wasn’t worried, as I knew there was a family history of ‘toenail’ issues? Now? I dunno, but who will ever know? Folks with PN have super fussy feet? WE HAVE THE FUSSIEST FEET, almost, ON EARTH!
BTW? Skin tags and patchy areas DO come with age at times? Derms can get them off if needed and it’s not too bad. At least? They’re not ‘catching’!
Good things to all!