Cellulitis is a common infection of the skin and the soft tissues underneath the skin. It occurs when bacteria invade broken or normal skin and start to spread under the skin and into the soft tissues.
This results in infection and inflammation. Inflammation is a process in which the body reacts to the bacteria. Inflammation may cause swelling, redness, pain, and/or warmth.
People at risk for developing cellulitis include those withtrauma to the skin or other medical problems such as the following:
- Circulatory problems such as inadequate blood flow to the limbs, poor venous or lymphatic drainage, such as after surgical vein harvesting, or varicose veins.
- Liver disease such as chronic hepatitis or cirrhosis.
- Skin disorders such as eczema, psoriasis, infectious diseases that cause skin lesions such as chickenpox, athlete's foot, or severe acne.
Cellulitis can occur in almost any part of the body. Most commonly, it occurs in areas that have been damaged or are inflamed for other reasons, such as inflamed injuries, contaminated cuts, and areas with poor skin condition or bad circulation.
The common symptoms of cellulitis are as follows:
- Redness of the skin.
- Red streaking of the skin or broad areas of redness.
- Pain or tenderness.
- Drainage or leaking of yellow clear fluid or pus from the skin; large blisters may occur.
- Tender or swollen lymph nodes near the affected area.
- Fever can result if the condition spreads to the body via the blood.
A number of factors can increase the chance that bacteria may invade the skin and cause infection.
These include the following:
- Injuries that break the skin.
- Infections related to a surgical procedure.
- Any breaks in the skin that allow bacteria to invade the skin (examples are chronic skin conditions such as eczema or psoriasis).
- Foreign objects in the skin.
- Infection of bone underneath the skin (An example is a long-standing open wound that is deep enough to expose the bone to bacteria. Sometimes this occurs in people with diabetes who have lost sensation in their feet).