Trench foot
The mainstay of treatment, like the treatment of gangrene, is surgical debridement, and often includes amputation. Self-treatment consists of changing socks two or three times a day and usage of plenty of talcum powder. Wherever possible, shoes and socks should be taken off, feet bathed for five minutes, patted dry, talcum powder applied and feet elevated to let air get to them.
Athlete's foot
To be effective, treatment includes all infected areas (such as toenails, hands, torso, etc.). Otherwise, the infection may continue to spread, including back to treated areas. For example, leaving fungal infection of the nail untreated may allow it to spread back to the rest of the foot, to become athlete's foot once again.