Phase one is the period of time when blood vessels are contricted by the cold and wetness inside the shoe or boot, and too little oxygen is carried to the cells of thefoot. The foot is cold to the touch, slightly swollen, slightly discolored, numb, maybe a little tender to touch. When the foot is rewarmed, the damaged tissue usually looks red, and feels sensitive, and the discomfort may last from hours to days. Phase two is the period when the cells of the foot have become damaged by the lack of adequate circulation. When the blood vessels open back up, the tissue swells with excess fluid.
Patients complain of tingling pain that never lets up.
A foot check will reveal swelling. On rewarming, blisters form, and, later, ulcers where the blisters have fallen off revealing dead tissue underneath. In severe cases, gangrene will result. Suffering may last from 2 to 6 weeks, and medications for pain are often prescribed. Phase three may last weeks to months.