How do soldiers avoid trench foot?

Dry feet.: It's important to keep your feet dry as possible. Carry an extra pair of socks with you at all times. Wet feet become macerated which allows bacteria and viruses in under the protective layer of skin.

Keep feet dry: Change socks and keep feet dry..Use anti fungus powder.

Trench foot: This is an exposure to damp cold wet conditions and poor hygiene. Doing all the things needed to keep your feet as dry and clean as possible keeps trench foot at bay . Adjunctive care like powder and antifungal preparations ( creams !) help as well.