Cellulitis is an inflammation of the connective tissue underlying the skin, that can be caused by a bacterial infection. Cellulitis can be caused by normal skin flora or by exogenous bacteria, and often occurs where the skin has previously been broken: cracks in the skin, cuts, burns, insect bites, surgical wounds, or sites of intravenous catheter insertion. Therapy is with antibiotics. It is unrelated to "cellulite", a nonpathological condition featuring dimpling of the skin.
Cellulitis is characterized by redness, swelling, warmth, and pain or tenderness. Cellulitis frequently occurs on exposed ares of the body such as the arms, legs, and face. Other symptoms can include fever or chills. In advanced cases of cellulitis, red streaks (sometimes described as ‘fingers’) may be seen traveling up the affected area. The swelling can spread rapidly.
Cellulitis is caused by a number of types of bacteria entering by way of a break in the skin. Group A streptococcus and staphylococcus are the most common of these bacteria, which are part of the normal flora of the skin but cause no actual infection until the skin is broken. Predisposing conditions for cellulitis include insect bite, animal bite, pruritic skin rash, recent surgery, athlete’s foot, swollen skin, dry skin, eczema, and burns.
The elderly and those with weakened immune systems are especially vulnerable to contracting cellulitis. Diabetics are particularly prone to cellulitis on the feet, as their disease impairs both the immune system and circulation, and ulcers which develop on their lower extremities may become infected. Immune-repressive drugs, HIV, and other illnesses or infections that weaken the immune system are also factors that make infection more likely. In addition, chickenpox and shingles often result in blisters which break, providing a gap in the skin which bacteria can enter through. Lymphedema, which causes swelling on the arms and/or legs, can also put an individual at risk.
Cellulitis is most often a clinical diagnosis, and local cultures do not always identify the causative organism. Blood cultures, if positive, usually provide a reliable etiology. Venography, leg scanning or impedance plethysmography can be used to distinguish venous stasis ulcers from lower extremity cellulitis.
Cellulitis can develop in as little as twenty-four hours, or can take days to develop.
In many cases, cellulitis takes less than a week to disappear with antibiotic therapy. However, it can take months to resolve completely in more serious cases, and can result in severe debility or even death if untreated.
If the case of cellulitis is minor, oral antibiotics may be all that are necessary. These are often intended to be taken for about ten days, and the patient usually sees his or her doctor after a day or two of taking the medication to insure that it is working correctly. In addition, the doctor may instruct the patient to elevate the affected area. Antipyretics or anti-inflammatory drugs may also be used.
If the oral antibiotics do not work or if the patient has a high fever when he or she comes to see the doctor, intravenous (IV) antibiotics will most likely be necessary. IV antibiotics can be administered at a clinic, the hospital, or the patient’s home. The specific antibiotic prescribed will depend on the physician's assessment as to the most likely causative bacteria: usually Gram-positive organisms will be covered, and in specific situations Gram-negative organisms, anaerobic organisms, or specific species will be covered.
In the most serious cases, when the cellulitis has spread to other tissue, especially bone (causing osteomyelitis), or where antibiotic therapy is unsuccessful, surgery may be necessary in order to remove the diseased tissue or bone.
In order to reduce the risk or being infected with cellulitis, it is advisable to wash any wounds an individual may have at least once each day with soap and to keep the wound covered with a bandage in order to prevent bacteria from entering and to ensure the wound is clean. In addition, changing bandages daily or when they become wet or dirty will reduce the risk of contracting cellulitis. It is also important to use antibiotic cream on recent wounds to disinfect them (MFMER, 2002). Finally, if an individual has a deep wound, bite, or cut, he or she should see his or her doctor about it (Klein, 2003).
Forms of cellulitis
A few of the forms of cellulitis are as follows: periorbital cellulitis (an infection of the eye socket) (Klein, 2003), necrotizing fasciitis, (MFMER, 2002), erysipelas (Britannica, 2003), clostridial cellulitis , nonclostridial cellulitis , and synergistic necrotizing cellulitis (Pankey, 1992). A few forms of cellulitis do not have some of the symptoms most commonly listed (for example, clostridial and nonclostridial cellulitis do not cause the skin to turn red [Pankey, 1992]), but the majority do.
- No author. "Cellulitis." Encyclopedia Britannica 2003. 15th ed. N.p.: Encyclopedia Britannica, Inc., 2003. CD-ROM.
- Klein, Joel MD. 'Cellulitis'. 2002. KidsHealth. 30 Oct. 2003 .
- MFMER. 'Cellulitis'. 3 July 2002. Mayo Foundation for Medical Education and Research. 30 Oct. 2003 .
- NLM. 'Group A streptococcal infections'. 2002. National Library of Medicine. 30 Oct. 2003 >.
- Pankey, George A. "Approach to rashes and infections of the skin and subcutaneous tissues." Textbook of internal medicine. 2nd ed. 2 vols. Philadelphia: J. B. Lippincott Company, 1992.