I completely empathise with this problem. I believe you have nothing to worry about.
Can I ask, do you have quite hot or sweaty feet?
I have a problem called 'hyperhydrosis'- in other words, I have uncontrollably sweaty feet and hands. As a result, every summer when the temperature increases, my feet tend to peel, sometimes in big strips, and sometimes just lightly like small blistering patches. This is because they are effectively rotting. You don't need to have hyperhydrosis for this to occur, so hearing that you get it after alot of walking and the same for all of the above mentioning D of E and soggy feet. If your feet are hot and wet for a prolonged amount of time, the skin can die.
There are many treatments for this. If you dont sweat alot, I would suggest wearing light socks and breathable shoes when walking, and washing your feet every day, drying them well, and moisturising. Also avoid bathing for hours and allowing your skin to wrinkle. Open shoes help too.
As for treatment of hyperhydrosis, I have tried and tested one treatment, "Endoscopic Thoracic Sympathectomy", which is to have a nerve cut near the collar bone, which ceases blushing and some sweating on one side of the body. If it succeeds you can have the other nerve cut for the other side. I had this done and although my sweating has decreases exponentially in one hand, I get compensatory sweating elsewhere. I also was one of the 2% of people who got 'Horners Syndrome' as a result of the operation, which I believe has ruined my face. Because of this I didn't want the second operation and so now blush noticably on one side of my face and not the other when exercising.
There is another treatment I have not tried, which is to put your feet in an electrolysed water bath twice a day. It passes currents through your feet which cease the sweating and therefore the foot-rot.
I do believe foot-rot is likely to be the case for you and certainly for the D of E girl mentioned above due to her activities.
Hope this is a help