UV light will make the fungi sterile. Fungi are very sensitive to sunlight and UV radiation. That's why trees moss up on the north side which gets the least amount of sun. Factories use UV light to keep vents clear of mold and fungi.

Sometimes just lying out in the sun for for twenty minutes a day can help clear up a fungal infection.

Many topical anti fungal creams are just not strong enough and don't do the job. Also, the fungi use any moisture to expand their colony and spread. And many medicines meant to be take internally are bad for the liver.

If it is something else, UV and sunlight will have little or no effect

DISCLAIMER: Not intended as medical advice. Consult your physician for diagnosis and treatment. ;)