Stage II ulcers present with partial thickness loss of dermis and a red-pink wound bed. No slough is present. Stage I ulcers have intact skin with a red area. The area may be firm, painful, soft, or cooler or warmer compared to adjacent tissue. Stage III ulcers have full-thickness skin loss and may contain slough. The wound may have visible subcutaneous tissue, and tunneling and undermining may or may not be present. Stage IV ulcers present with full-thickness skin loss and exposed bone, muscle, or tendons. Eschar and slough may be present, and tunneling and undermining may develop. Unstageable wounds cannot be staged due to eschar or slough covering the wound. The wound bed must be visualized in order to stage the wound.