Definition

Cellulitis refers to an infection of the skin that may spread to tissue just beneath the skin's surface. It may occur anywhere on the body, but most commonly affects the face or lower legs.

Causes

Cellulitis is usually caused by a bacterial infection. The infection may come from bacteria that normally lives on the skin or bacteria from other sources. The bacterial infection may be caused by:

• A minor injury to the skin, such as a cut, scratch, blister, puncture, or bite, that becomes infected and spreads into the surrounding skin
• Chickenpox blisters that open up and become infected with bacteria
• Injuries that occur in natural bodies of water that become infected with germs found in the water
• A cut or abrasion that becomes infected by food bacteria while handling fish, poultry, eggs, or meat
• Bacteria that enter the body through surgical wounds or a catheter in a vein
• Infection in a person with diabetes or a weakened immune system
• Bacteria spreading from an upper respiratory or ear infection
• Impaired circulation (tends to cause recurrence of cellulitis)

Puncture Wound

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Risk Factors

A risk factor is something that increases your chance of getting a disease or condition.

Risk factors include:

• Insect, animal, or human bites
• Diabetes
• Weakened immune system, such as AIDS
• Alcoholism
• Chronic use of steroids
• Kidney and liver failure
• Surgical procedures
• Poor circulation or peripheral vascular disease
• Swelling or fluid retention
• Intravenous drug abuse
• Burns
• Exposure to fish, meat, hides, shellfish, poultry, or eggs

Symptoms

Symptoms may begin within hours or days and can include:

• Skin inflammation that begins in a small area and spreads. This includes:
  • Redness
  • Pain or tenderness
  • Swelling
  • Warmth
  • A red streak (possibly)
• Swollen lymph nodes
• Fever or chills
• Fatigue
• Headache
• Cellulitis near the eyes may cause pain with eye movements and should be treated urgently

Diagnosis

The doctor will ask about your symptoms and medical history, and perform a physical exam. Expect to answer questions about how the wound occurred and exposure to animals or natural bodies of water. Your skin will be closely examined. Using a colored pen on your skin, the doctor can mark the border of the cellulitis to monitor its progress.

Tests may include:

Wound culture—a sterile applicator swabbed across the area and sent to a lab to be tested for bacteria and type of antibiotics to use in treating the infection. (This test is rarely, if ever, performed anymore since the bacteria on the swab will reflect the bacteria that colonize our skin normally and, hence, the test is not useful.)

Blood tests—to help determine the severity of the infection

X-rays, bone scans, or CAT scans—to check for gangrene under the skin or evidence that the infection has spread to the bone

Treatment

The treatment goal is to eliminate the infection and reduce discomfort. Most cases of cellulitis resolve after a week or two of treatment. An infected wound can be cleaned and any dead tissue removed. If a collection of pus (called an abscess) is present, it can be drained. Severe cellulitis, cellulitis in a diabetic or immune suppressed person, or an infection on the face may require hospital care.

Treatment includes:

Prevention

To reduce your risk of getting cellulitis:

• Keep your skin clean
• Moisturize dry skin with lotion
• Avoid injury to the skin
  • Wear protective gear when participating in sports
  • Wear long pants and long-sleeved shirts when hiking
  • Wear sandals when at the beach, rather than going barefoot
  • Be careful around animals, treat pets with respect to avoid bites
• If you or your child has not had chickenpox, talk to your doctor about getting vaccinated
• Do not swim in natural waters if you have cuts or sores
• Try not to cut yourself during fishing or other water sports
• If a small cut, bite, or other injury occurs, carefully tend to the wound.
  • Clean cuts or scrapes with soap and water
  • Apply antibiotic ointment
  • Cover with a bandage or dressing
  • Do not scratch wounds
  • Call the doctor immediately if the area becomes red or inflamed
• Seek prompt medical care for larger wounds or bites
• If your legs tend to swell, elevate them several times a day and wear support stockings
• Get recommended vaccines for children and adults