Cellulitis

What Is It?

Cellulitis is a serious bacterial infection of the skin. Bacteria break through the skin's protective outer layer, typically at the site of an injury, such as a cut, puncture, sore, burn or bite. Cellulitis can occur at the site of surgery, or where the skin was punctured for a small plastic tube (intravenous catheter) used to administer medications. Once inside the skin, bacteria multiply and make chemicals that cause inflammation in the skin.

Cellulitis usually occurs on the legs and feet. However, it can develop on any part of the body, including the trunk, arms and face. It often develops near an area where there already is swelling, poor blood flow, or another skin condition such as a fungus infection between the toes (athlete's foot).

Many types of bacteria can cause cellulitis. Most cases are caused by Streptococcus pyogenes (strep) or Staphylococcus aureus (staph). Other types of bacteria can cause infection after certain types of injuries, such as animal bites, puncture wounds through wet shoes, and wounds exposed to freshwater lakes, aquariums, or swimming pools.

Cellulitis can take several forms, including:

• Periorbital cellulitis, a skin infection around the eye sockets Often, this is caused by Haemophilus influenza, a type of bacterial infection that is common in children. Because infection around the eye can spread to the brain, periorbital cellulitis requires prompt medical attention.
• Erysipelas, a skin infection that causes raised, firm, bright red patches of skin Usually, it is caused by Streptococcus bacteria. Erysipelas occurs most often on an arm or leg that has been damaged by previous surgery or is chronically swollen due to poor lymph flow (lymphedema). Erysipelas also can develop on the face, typically across the bridge of the nose and upper cheeks.
• Necrotizing fasciitis, also known as "flesh-eating strep" This is an infection of the tissues below the skin, rather than the skin itself. Often, the skin in the area is discolored and extremely painful. Fasciitis is a life-threatening infection that requires prompt medical attention.

Symptoms

In cellulitis, the affected skin feels warm and is usually red, swollen and painful. The redness can be slight or can stand out compared to surrounding skin. The area of warmth can be felt with the back of the hand, especially when compared to surrounding skin. There may be a spreading network of red streaks in the skin, caused by infection in the vessels that carry lymph (tissue fluid), as well as enlarged lymph nodes (swollen glands) near the area of infection.

Fever and a general sick feeling (malaise) often accompany cellulitis. Severe infections can cause low blood pressure if bacteria get into the bloodstream. Bloodstream infections (blood poisoning) from cellulitis are particularly dangerous in the very young and very old, as well as in those with weakened immune systems or abnormal heart valves.

Diagnosi

you about how your cellulitis developed and about your symptoms, including whether you have:

• Had recent injuries such as cuts, scrapes, bites or puncture wounds
• Previously injured the area or been operated on
• Been exposed to fish tanks, pond water or animals
• Had medical problems that increase your risk of complications
• Shaking chills or other symptoms that suggest the infection has spread to the bloodstream or to surrounding organs

Many people who develop cellulitis have no other medical problems and no obvious injury or skin damage that allowed the infection to occur.

Your doctor can usually diagnose cellulitis based on the injury, your symptoms and the results of a physical examination. If your wound is draining fluid or pus, your doctor may take a sample to identify the type of bacteria. This allows the doctor to precribe specific antibiotics to eliminate the bacteria. Your doctor may recommend tests to look for other conditions that may mimic cellulitis. For example, an ultrasound of the veins in your leg can help detect a blood clot. X-rays can help to determine whether the skin infection has spread to the bone.

Expected Duration

How long cellulitis lasts depends on the type of injury, the bacteria that caused the infection and your general health. Without proper antibiotic treatment, some forms of cellulitis can cause serious complications within a few days, even in otherwise healthy people.

Prevention

To help prevent cellulitis:

• Prevent skin injury Wear protective gloves while gardening and working outdoors. Wear long sleeves and trousers while hiking. Avoid going barefoot outdoors. Wear protective padding on elbows and knees while skating.
• Treat minor skin wounds promptly Gently wipe away dirt, wash with antibiotic soap, apply antibiotic ointment and cover with a clean bandage.
• Seek medical attention Medical attention is needed for all deep puncture wounds and animal bites and for all deep wounds involving a joint, hand or foot.

Treatment

Cellulitis is treated with antibiotics. Your doctor will choose a specific antibiotic depending on the site of your cellulitis and the likely cause of your infection. Most cases of cellulitis improve quickly once you start taking antibiotics.

If you have mild cellulitis, you can usually treat it at home with antibiotics taken by mouth. However, keep in touch with your doctor to be sure that the infection is improving as expected. At home, warm compresses, such as a warm, moist washcloth, and elevating the infected area can help. If you have severe cellulitis, you may need to be treated in the hospital with antibiotics given intravenously (into a vein).

When To Call A Professional

Call your doctor whenever a skin injury becomes red, warm, swollen or tender. Call your doctor promptly if you get a deep puncture wound, especially on a hand or foot, or if you are bitten by an animal or human.

Prognosis

In most cases, symptoms of cellulitis begin to improve within 24 to 48 hours after starting treatment with appropriate antibiotics. Always take all the antibiotics prescribed by your doctor, even if you think your infection has been cured. The prognosis is generally good, but the condition can return, especially in people with poor circulation, chronic (long-term) swelling in the legs or skin that is in poor condition.

Additional Info

National Center for Infectious Diseases

Travelers' Health

Centers for Disease Control and Prevention

1600 Clifton Road, NE

Atlanta, GA 30333

http://www.cdc.gov/travel/