Pressure ulcers, i.e. decubitus ulcers, are usually categorized into the period of hemorrhagic erythema, inflammatory infiltration, superficial ulceration, and necrotic ulceration. 1. Bruising and erythematous stage: local skin is not obviously broken, the epidermis is relatively intact, the main manifestation of the local pressure site has erythema, pain, epidermal temperature is high or low, and numbness and so on. 2. Inflammatory infiltration period: localized red and swollen skin breakage, causing blisters and ulcers, blisters broken, the affected area shows moist and red, the patient has a sense of pain. 3. Shallow ulcer stage: epidermal necrosis exists, the main symptom is that the local blisters rupture, the affected area exudes yellow liquid with pus, and there may be necrotic skin tissues or putrefied flesh. 4. Necrotic ulcer stage: the skin is severely damaged, the local skin is black, not only the epidermis is necrotic, but also the fat layer as well as the muscle tissue, there is a pungent odor and secretion in the bones, and sepsis may be induced. There are other clinical manifestations of pressure ulcers, and it is recommended that patients who experience discomfort should consult a doctor in time to identify the cause and then treat accordingly under the guidance of the doctor.