Final answer:
The first sign of a developing pressure ulcer is a change in skin color to red, which, if not relieved, may progress to darker colors like purple or blue.
Step-by-step explanation:
The first indication that a pressure ulcer may be developing when a nurse notices that the skin has turned a different color. During the initial stages of a pressure ulcer, especially in individuals with lighter skin tones, the skin may present as a persistent area of redness. If the pressure is not relieved, this area can progress to a darker purple or blue color as blood flow is further reduced and tissue damage occurs. In darker skin tones, the affected area may appear with a different hue, such as purple, blue, brown, or black, compared to surrounding skin. It's essential for healthcare providers to be vigilant in assessing skin changes because early detection and treatment of pressure ulcers are important to prevent further tissue damage and potential complications.