Hello:
You don't mention having any pain, sores or lesions associated with this; therefore, I am going to suggest a few ideas on how to prevent this.
If this is your only problem, then it sounds like you are (believe it or not) exfoliating your feet by friction between your feet and shoes when socks aren't worn.
Prior to going to bed, put lotion on your feet (Aveeno) is one of the best or (Eucerin Cream) and wear socks over this. If it is only dry skin either of these will do the trick. You should repeat this every night for a week and then repeat every third night....
Exfoliation can be a good thing, but too much can be more harm than good. Exfoliating removes the outer layer of the dermis. If you are not applying lotion frequently to the feet, but exfoliate often, moisture is "being lost" so to speak.
Get rid of the medication for Athletes feet. It contains medication that will dry the skin. This is essentially defeating the purpose of hydrating, or applying lotion.
If any kind of redness occurs or scaly patches appear, it could be suggestive of psoriasis or exzema. You would want to use the Eucerin cream as it is more emollient that the Aveeno lotion.
If the above suggestions leave you without positive results, you should see a dermatologist. You may have some type of psoriasis or exzema and need a stronger medication. Based on your description, I highly doubt this. But, it's always better to be safe than sorry!
If this has been helpful to you please do accept. Positive feedback ia also appreciated.
Terri L. Romaker