Cellulitis
Definition
Cellulitis refers to an infection of the skin. It may spread to tissue just beneath the skin's surface. The infection may occur anywhere on the body. It is most common on the face or lower legs.
Causes
Cellulitis is often caused by a bacterial infection. It 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)
- MRSA infection —drug resistant infection that can be spread through shared towel or sport equipment
Puncture Wound
Risk Factors
Factors that increase your risk for cellulitis include:
- Insect, animal, or human bites
- Diabetes
- Weakened immune system, such as AIDS or being on chemotherapy
- 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 raw 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 with:
- 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. A physical exam will be done. Expect to answer questions about how the wound occurred. Your doctor will also ask about exposure to animals or natural bodies of water. Your skin will be closely examined. The doctor may use a colored pen to mark the border of the cellulitis. This will help to monitor its progress.
Tests may include:
- Wound culture—a sterile applicator swabbed across the area and sent to a lab to test for bacteria; will help to determine type of antibiotic to use (not very useful if there is no pus drainage, open wound or an abscess.)
- Blood tests—to help determine the severity of the infection
To check for gangrene under the skin or evidence that the infection has spread to the bone the doctor may order:
- X-rays
- MRI scan —magnetic waves are used to make pictures of structures inside
- Bone scans, or CAT scans
Treatment
The goal is to eliminate the infection and reduce discomfort. Most cases resolve after a week or two of treatment. An infected wound can be cleaned. Dead tissue may be removed.
A collection of pus may develop. This is called an abscess. It can be drained.
Severe cellulitis, cellulitis in a person with diabetes or a person with a poor immune system, or an infection on the face may require hospital care.
Treatment includes:
Medication
Antibiotics may be taken by mouth or injected into a muscle or vein. The method will depend on the severity of the infection.
Take the entire prescription as directed. Make sure to use all the medicine given. If not taken fully, the infection may return.
Supportive Care
This may include:
- Resting in bed or elevating the infected area higher than your heart.
- Applying warm or cool compresses to the area.
- Change your dressings as directed by your doctor.
- Protect your skin from additional injury.
- Do not scratch or rub the area.
If you are diagnosed with cellulitis, follow your doctor's instructions .
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 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.
RESOURCES:
American Academy of Dermatology
http://www.aad.org/
National Institute of Allergy and Infectious Diseases
http://www.niaid.nih.gov/
CANADIAN RESOURCE;
Canadian Dermatology Association
http://www.dermatology.ca/
Health Canada
http://www.hc-sc.gc.ca/
References:
American Medical Association website. Available at: http://www.ama-assn.org/ .
Cecil Textbook of Medicine . 21st ed. WB Saunders Company; 2000.
Clinical Dermatology . 3rd ed. Mosby-Year Book, Inc.; 1996.
Conn's Current Therapy 2001 . 53rd ed. WB Saunders Company; 2001.
Griffith's 5-Minute Clinical Consult . Lippincott, Williams and Wilkins; 2001.
Harrison's Principles of Internal Medicine . 14th ed. The McGraw-Hill Companies; 2000.
Principles and Practice of Infectious Diseases . 5th ed. Churchill Livingstone, Inc.; 2000.
Stevens DL, Bisno AL, Chambers HF, et al. Practice guidelines for the diagnosis and management of skin and soft tissue infections. Clin Infect Dis . 2005; 41: 1373-406.
Last reviewed February 2009 by Ross Zeltser, MD
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.
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