Definition

Cellulitis is an infection of the skin and tissue just below the skin. The infection may occur anywhere on the body. It is most common on the lower legs.

Causes

Cellulitis is caused by a bacterial infection. It may come from bacteria that normally live on the skin or bacteria from other sources. The bacteria enter the skin through a cut or injury. The infection spreads into the surrounding skin.

Risk Factors

Factors that may increase the chance of cellulitis include:

• A minor injury to the skin such as, a cut, scratch, blister, burn, puncture, or bite
• Injuries that occur in natural bodies of water
• A cut or abrasion
• Bacteria that enter the body through surgical wounds or a catheter in a vein
• Having certain conditions such as diabetes, HIV, kidney or liver disease, or poor circulation
• Abusing alcohol or drugs
• Taking steroids on a regular basis
• Undergoing surgery
• Retaining fluids
• A fungal infection of the foot
• Handling certain foods, like raw fish, meat, shellfish, poultry, and eggs

Symptoms

Symptoms may begin within hours or days and can include:

• Skin inflammation that begins in a small area and spreads with:
  • Redness
  • Pain or tenderness
  • Swelling
  • Warmth
  • Streaking—spreading of redness
• Swollen lymph nodes
• Fever or chills
• Fatigue
• Confusion

Cellulitis near the eyes may cause pain with eye movements and should be treated right away.

Diagnosis

You will be asked about your symptoms and medical history. A physical exam will be done. Your doctor will also ask about exposure to natural bodies of water or animals. Your skin will be closely examined. The border of the cellulitis on your skin may be marked. This will help to monitor its progress

Tests may include:

• Wound culture to test for the bacteria causing the infection
• Blood tests to see if the infection has spread to the bloodstream

In severe cases, the infection can lead to tissue death known as gangrene. It can also spread to the bone or other structures.

Images may be taken of your bodily structures. This can be done with:

• X-ray
• MRI scan
• CT scan
• Bone scan

Treatment

The goal is to eliminate the infection and reduce discomfort. Most cases resolve after 1-2 weeks of treatment.

Hospital care may be needed if you have:

• Severe cellulitis
• Diabetes or a weakened immune system
• An infection on your face

Treatment includes:

Prevention

To help reduce your chance of cellulitis:

• Keep your skin clean and dry.
• Moisturize dry skin with lotion.
• Avoid injury to the skin:
  • Wear protective gear 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.
• 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 care for the wound:
  • Clean cuts or scrapes with soap and water.
  • Apply antibiotic ointment.
  • Cover wounds with a bandage or dressing.
  • Do not scratch wounds.
  • Call the doctor right away if the area becomes red or inflamed.
• Seek prompt medical care for larger wounds or bites.
• Wash your hands after coming in contact with fish, poultry, eggs, or meat. Do not handle these items if you have cuts or sores.
• If your legs tend to swell, elevate them several times a day and wear support stockings.
• Get recommended vaccines for children and adults.

National Institute of Allergy and Infectious Diseases http://www.niaid.nih.gov

Health Canada http://www.hc-sc.gc.ca

Cellulitis and erysipelas. National Institute of Allergy and Infectious Diseases website. Available at:
http://www.niaid.nih.gov/topics/cellulitiserysipelas/pages/default.aspx
Updated November 8, 2013. Accessed August 5, 2015.

Stevens DL, Bisno AL, Chambers HF, et al. Practice guidelines for the diagnosis and management of skin and soft tissue infections: 2014 update by the Infectious Diseases Society of America. Clin Infect Dis. 2014;59(2):147-159.