What is cellulitis?

Definition

Cellulitis is a bacterial infection of deep skin
tissues. Bacteria enter the skin through cuts, insect bites, and sores. Persons
who are debilitated, such as older adults, diabetics, or persons unable to fight infection, may develop
cellulitis without a break in the skin.

Causes

Streptococcal and staphylococcal bacteria are the most common causes of cellulitis. Methicillin-resistant Staphylococcus aureus
(MRSA) infections that lead to cellulitis are often obtained in hospitals. Although bacteria are normally found on the skin, they do not cause problems unless there is a break in the skin.

Risk Factors

Any exposure to bacteria may lead to cellulitis. People who work in gardens or
other outdoor areas without gloves may get bacteria from the soil. Handling
poultry, fish, or meat without gloves or without careful handwashing also exposes
a person to bacteria. Any break in the skin from, for example, surgery,
liposuction, eczema, illegal drug use, or athlete’s foot may allow cellulitis to
develop. Athletic events, athletic facilities, day care, and other crowded areas
are also sources for infections, including infections with MRSA. Swelling in the
legs (edema) from diseases such as peripheral artery disease, even
without a break in the skin, may lead to cellulitis.

Symptoms

Redness, tightness, and a glossy look to the skin are symptoms of cellulitis. The area may grow in size and be painful and tender. Fever, chills, and muscle aches may indicate infection. Another symptom is a skin rash that appears suddenly and spreads.

Screening and Diagnosis

There is no screening for cellulitis. A physician usually makes the diagnosis
by observing the area of redness. In rare cases, radiology tests such as
ultrasound, magnetic resonance imaging, or a
computed
tomography scan may be used to rule out other problems.

Treatment and Therapy

The primary therapy for cellulitis is antibiotics,
drugs that are prescribed to fight infections. A doctor will carefully monitor the
initial response to antibiotics to be sure the infected area gets better with
treatment. If the cellulitis does not improve, the doctor may take blood samples
to determine what bacteria are involved in the infection and thus to find a more
appropriate antibiotic. In rare cases, sepsis (bacteria in the bloodstream)
may occur, leading to the need for additional laboratory blood work. Antibiotics
may be given by mouth (orally). For cases in which the infection is more severe or
does not respond to oral antibiotics, intravenous antibiotics (administered
directly into the bloodstream using a needle) may be indicated; admission to a
hospital is likely too. Local treatment of the infected area may include elevating
the area and applying moist dressings. If not treated, cellulitis can cause more
serious problems, including meningitis, infection in the bone, and
gangrene (tissue death).

Prevention and Outcomes

Preventing cellulitis means taking care of the skin. Cleanliness; wearing
gloves when needed; treating cuts, scrapes, and bites promptly; and treating any
skin
infections such as athlete’s foot immediately are important
preventive measures. Persons with risk factors for cellulitis should discuss with
their doctor the ways to prevent its development, including taking antibiotics on
a regular basis.

Bibliography

Archer, G. L. “Staphylococcal Infections.” Andreoli and Carpenter’s Cecil Essentials of Medicine. Ed. Thomas E. Andreoli et al. 8th ed. Philadelphia: Saunders, 2010. Print.

Berman, Kevin. "Cellulitis." MedlinePlus. Natl. Lib. of Health, 15 May 2013. Web. 29 Dec. 2015.

"Cellulitis." Mayo Clinic. Mayo Foundation for Medical Education and Research, 11 Feb. 2015. Web. 29 Dec. 2015.

Hall, John C. Sauer’s Manual of Skin Diseases. 9th ed. Philadelphia: Lippincott, 2006. Print.

Stevens, Dennis L. “Infections of the Skin, Muscle, and Soft Tissues.” Harrison’s Principles of Internal Medicine. Ed. Joan Butterton. 17th ed. New York: McGraw-Hill, 2008. Print.

Swartz, Morton N., and Mark S. Pasternack. “Cellulitis, Necrotizing Fasciitis, and Subcutaneous Tissue Infection.” Mandell, Douglas, and Bennett’s Principles and Practice of Infectious Diseases. Ed. Gerald L. Mandell, John E. Bennett, and Raphael Dolin. 8th ed. Philadelphia: Elsevier, 2015. 1194–215. Print.

Turkington, Carol, and Jeffrey S. Dover. The Encyclopedia of Skin and Skin Disorders. New York: Facts On File, 2002. Print.