I shouldn't be saying this but I'm a glad to hear that I'm not dealing with this alone. Something unavoidable in late diagnosis of CF are all the issues that fit like a glove, in retrospect. Beyond a doubt, prevention is better than having to cure the fungus among us.
Candida, a specific yeast that loves our wet and relatively sticky membranes. Women are more often aware of the side effects of antibiotics when the balance of bacteria and yeast get off kilter and yeast overwhelms the vulva and another itch has to be treated.
Treating a nail fungus, Candida, is most effective with Diflucan or other other oral fungal medicine. The obvious downside is another imbalance in areas where fungus, bacteria and such are attempting a balance. Topical treatment of the feet and nails can be effective depending upon the severity of the infection. The advantage is localized treatment just like Monostat, a local treatment. It's tricky to get prescription oral treatment. Your doctor may have to be creative and order it for systemic Candida. It's not that uncommon in CFers.
I've been fighting foot fungus, toe fungus, jock itch, thrush, abdominal candida and nasal/sinus fungal overgrowth for ever. The doctor suggested that I go barefoot the summer when I was 6. My athletes foot was a mother's nightmare. The only thing available was torture in a bottle called NP 27. The main ingredient was alcohol and some horrible antifungal agent. The skin of my toes were split beyond the first joint. The only time I've ever seen my mother strike a stranger was my dramatic claims that I could see the bones in my feet if I spread my toes. The doctor spread two toes, I screamed and after he exclaimed something like 'God, you can see the bones!' My mother biffed him on the back of his head, saying something about his bed side manner.
Wicking socks need to send the water somewhere. I wear a thin wicking sock and a cotton/polyester over sock. I alternate shoes every other day, put OdorEater inserts in my shoes and change them monthly. I suggest Lotramine spray for your feet and shoes. A bunch of stuff involving diet, natural remedies and such is available and might be just the thing, I don't know anything about them. Keeping dry feet is not cheap, 2-3 pairs of shoes, extra socks and a mid day change of some or all the footwear's feels like heaven but it's another thing to maintain. The copper infused "Tommy Copper" wicking socks are not a gimmick here. Copper and sweat make copper sulfate, a good anti fungal.
Just a thought,
LL