It is tinea, fungus. Actually it is called "moccasin tinea". Do what I do. In 500mls cheap vinegar, mix two capful of tea tree oil. Apply every day to your feet, sole, under toes. In a week you should have visible results. It also helps with foot odour, very refreshing for feet. I use it every morning. Mixture penetrates quickly, but if no time, use hair dryer to dry feet quickly. Don't spen any money on over the counter creams. I did, was no use.