Stress caused by excess body weight and the impact of the foot striking the ground may result in pressure ulcers. They are most common in diabetics and may occur on the ball of the foot, big toe or heel. Infection from the sore may enter the blood stream or bone putting you at risk for a more serious infection.
A callus forms from friction against the bottom of the foot. Thickening of the skin, caused by the callus, kills healthy tissue and causes pain. Peripheral neuropathy limits the feeling in the foot and may prevent you from noticing the pain from the callus. Ulcers form where healthy skin dies and may quickly change from a 'hot' spot into an infected wound.
Pressure or friction causes red hot spots on the skin. These spots can develop into a blister if pressure is not relieved and may result in an open wound or corn. Ulcers can be formed when corns and calluses press on the inner layers of skin and fat. Infections may enter through these ulcers. Infected ulcers may kill healthy tissue and begin to drain white, yellow or greenish discharge. They may also bleed or have an unusual odor.
Physicians may prescribe medications for infected hot spots, small cracks or sores. Removing thickened skin and applying medication may be necessary for healing the wound. Custom orthotics (arch supports) take pressure off hot spots and ulcers. In some cases, surgery may be necessary.