Cellulitis (Infection)

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Cellulitis (infection)


Cellulitis is an infection of the surface (epidermis layer) and deep layers (dermis and subcutaneous tissue) of the skin caused by bacteria that enter through a break in the skin.


Skin that is intact is a barrier to the many types of bacteria that exist on its surface. When the skin surface is damaged, bacteria can enter the body, and a localized infection can occur. The most common site for

cellulitis is on the upper or lower extremities, but it can occur anywhere on the body, even the face. The most common bacteria involved in cellulitis are Group A streptococci and Staphylococcus aureus. Impetigo, an infection of the surface of the skin, or stasis dermatitis , scaling and redness of the lower leg caused by poor circulation, may be mistaken for cellulitis.


Cellulitis is more common in males and adults aged 45 to 64 years. Occurrence is equal in all races. Individuals with a weakened immune system (e.g., in cases of leukemia and HIV infection, alcoholism, and diabetes) are at increased risk for cellulitis. Individuals with poor circulation, a history of obesity , a history of surgeries, including dental procedures, and pregnancy are also at risk for developing cellulitis. Use of drugs that suppress the immune system (which reduce the chance of organ rejection after transplant) and corticosteroids (drugs that reduce inflammation and swelling) are also risk factors for the development of cellulitis. Blisters from chickenpox and shingles can serve as a route of entry for bacteria entering the body. Chronic swelling of the lower extremities (edema ), chronic fungal infections of the feet or toes can cause the skin to crack resulting in a bacterial infection. Individuals with a history of using intravenous drugs, eczema, and psoriasis are also predisposed to developing cellulitis.

Causes and symptoms

Bacteria normally exist on the surface of the skin, but when a break in the skin occurs through a cut, wound, burn, insect bite, trauma, or surgical incision, bacteria can enter the body and multiply causing infection and inflammation. When infected, the skin becomes red, feels warm to the touch, is inflamed, swollen, and tender. These local symptoms may be accompanied by a fever and a generalized feeling of illness (malaise). As the infection spreads, redness and inflammation increase in size. Red streaks may extend from the infected area if the infection spreads to the blood vessels or lymph channels. There may be blisters, which may be filled with fluid or pus (abscess). The lymph nodes may become enlarged (swollen glands) and sensitive to touch. Cellulitis over a joint may cause pain and stiffness in movement due to tissue swelling. If the infection enters the blood, the condition becomes more serious. Infection of the blood system by cellulitis occurs in up to 40% of people with cellulitis. Symptoms may appear hours to days after the infection begins, and the infection may spread rapidly.


A preliminary diagnosis may be made by a physician based on the appearance of the skin and the symptoms that are present. Blood tests, wound cultures, x rays, and bone scans may be ordered.

Blood tests may include a complete blood count (CBC) to detect if the white blood cell (WBC) count is elevated, which indicates the presence of infection. If a blood system infection is suspected, a blood culture may be done, but it is not usually required for most patients. x ray or bone scan may be done to determine if the infection has spread to the bone. Other tests may be ordered to determine if the condition is cellulitis or actually a blood clot since symptoms for these two conditions can be similar.


Treatment is dependent on the location and degree of cellulitis, the type of bacteria causing the infection, and the individual's general medical condition. With seven to ten days of antibiotics , the infection usually resolves in a week or two. Oral antibiotics are prescribed for uncomplicated cases of cellulitis. Intravenous antibiotics administered in a hospital setting may be required if symptoms do not improve on oral antibiotics, symptoms are severe, or symptoms are accompanied by a high fever. Surgical drainage of collections of pus or debridement to remove infected tissues is sometimes needed. If tissue death (gangrene ) has occurred, surgery may be necessary to remove infected tissue.

Nutrition/Dietetic concerns

No nutrition or dietetic concerns or restrictions exist.


Over-the-counter (OTC) pain medication or warm or cool moist compresses may be used to relieve discomfort. If the infection is in a limb, keeping the limb elevated above the level of the heart and immobile may reduce swelling and discomfort. Surgery may be required to remove dead tissue that occurs. Wound care must be adhered to as prescribed. Everyone ought to avoid rubbing, squeezing, or scratching the affected area.


Outpatient treatment resolves the infection in 90% of cellulitis cases. If cellulitis is not treated adequately or is left untreated, it can result in a blood infection, gangrene, and death. Complications of cellulitis may include infection of the valves of the heart and kidney inflammation. Cellulitis may also contribute to the development of blood clots in the lower extremities.


The skin needs to be kept clean and moisturized to decrease drying and prevent cracking. Individuals need to protect their skin, including hands and feet, from injury by wearing protective clothing and shoes. Skin breaks need to be kept clean with soap and water and use of antibiotic ointment, and signs and symptoms of infection, including redness and pain, need to be monitored. Skin breaks ought to be covered with a bandage or dressing. If the affected area shows signs of infection, individuals should seek medical advice as soon as possible. If a physician prescribes an antibiotic for an infection, they should take the medication as prescribed. Staying in good health and controlling chronic health problems will assist in preventing infection. Meticulous skin and nail care for diabetics is essential in reducing risk of infection.


  • What causes cellulitis?
  • How can I prevent cellulitis?
  • What symptoms indicate that I have cellulitis?
  • How will cellulitis affect my health?
  • What treatments will be used to treat cellulitis?
  • How can I care for cellulitis at home?
  • Will I have to be hospitalized?
  • How can I keep cellulitis from recurring?

Caregiver concerns

Caregivers need to ensure that the antibiotic is taken as prescribed. They need to provide skin care for the infected area as prescribed. Too, they need to be aware of what symptoms they should watch for and what course of action to take if symptoms do not improve, symptoms worsen, or new symptoms develop. Individuals need to remember that cellulitis is not contagious.



Cunningham, Dennis. “Cellulitis.” eMedicine.com. January 8, 2007. http://www.emedicine.com/MED/topic310.htm.

Halachmi, Shlomit. “Cellulitis.” MedlinePlus.com. July 27, 2006. http://www.nlm.nih.gov/medlineplus/ency/article/000855.htm.

June G. Borazjani R.N., S.N., C.P.H.Q.