Nail stuff, especiallly toe nails are tough

to treat, even if you go barefoot [I KNOW I never go barefoot but to bathe].
Toes are nice dark places that have nice dark and delitefully moist nooks and cranny’s that can pick up all sorts of ‘wondrous wildlife’…so to speak.
Podiatrist first, then dermatologist if it is ONLY the feet involved. GP’s or Internal Med. docs are well, ok for some? But why not go to someone who ‘does’ nothing BUT feet?
Harder tho, to get docs reporting or ‘talking’ to each other? Sometimes it takes that sort of communication between medical disciplines to sort the real problem out.
Good luck?!!!!!! I hope you get ‘rid of IT!’ Whatever IT is!