Pressure ulcers are caused by unrelieved pressure, applied with great force over a short (or with less force over a longer period), that disrupts blood supply to the capillary network, impeding blood flow and depriving tissues of oxygen and nutrients.

This external pressure must be greater than arterial capillary pressure to lead to inflow impairment and resultant local ischemia and tissue damage. See: classification of superficial pressure sores. Predisposing factors are classified as intrinsic (e.g. limited mobility, poor nutrition, aging skin) or extrinsic (e.g. pressure, friction, shear, moisture). The most common sites for pressure ulcers are the sacrum, heels, ischium, tuberositiesn greater trochanters and lateral malleoli.

Classification of superficial pressure sores :

• Stage I: Non-blanchable erythema of intact skin
  • A bedsore appears first as a reddened area of skin, which then starts to break down to form an open, raw, oozing wound. Stage I has unbroken, but pink or ashen (in darker skin) discoloration with perhaps slight itch or tenderness. The discoloration is permanent, even when pressure is relieved; the skin is pink/red and does not become white when you put a finger on the affected area. Usually over bony prominence. The affected tissue may be painful, firm, soft, or warmer or cooler compared with adjacent tissue.
• Stage II: Red, swollen skin with a blister or open areas
  • Partial-thickness loss of dermis appearing as a shallow, open ulcer with a red-pink wound bed, without slough; may also appear as an intact or open/ruptured serum-filled blister.

How to deal with supperficial pressure sores?

Do not attempt self-care for any ulcer beyond stage II in appearance. 
The area may heal with relief of pressure and by applying care to the affected skin. A good diet will aid skin healing, especially by taking in enough vitamin C and zinc, which are available as supplements.

Effective skin care:

• If the skin is not broken, gently wash the area with a mild soap and water.
• Clean open sores on the skin with a saline solution.
• Apply a soft silicone dressing with ReSkin technology on the wound or on the area to protect.
• Be sure to keep urine and stool away from the affected areas.

Relieve pressure:

• Change position often (every 15 minutes in a chair and every 2 hours in a bed)
• Use special soft materials or supports (pads, cushions, and mattresses) to reduce pressure against the skin.