Mild foot itch can be caused by fungi or bacteria that live on your feet. In mild cases, these skin irritating organisms live primarily on the skin's surface. The good news is they can easily be treated with many good over-the-counter products found at your local pharmacy.
However, with extreme and chronic foot itch, these fungi and bacteria may have penetrated into your skin's lower layers. They can hide and thrive inside and underneath dead, calloused skin, making it difficult for most medications to reach.
Killing surface fungi and bacteria can bring much needed relief. But it's usually only temporary. Hidden fungi and bacteria living just under your skin’s surface may have only been weakened and not destroyed. They are left to reproduce, re-infect and come roaring back. This is called a flare-up.