I am no Doctor but I have a suggestion, You say it is an Fungal infection.athletes foot. Hoof and mouth dasease. Have them do a blood test to see if she has a blood yeast infection...
does she have any foot pain. Off and on there is also a toxicity test she can take to see if it is mold related toxicity blood test......
Mold in your house or under the house in the walls ... mold spores also could be a factor. . fluconizole for athlete's foot see about that just putting it out there ,,myself l have been fighting hosheshumoto thyroiditis atrophy hypothyroidism uncontrolled now total thyroid atrophy with mild pituitary atrophy,,,, according to the indocornaligist as of present day