Overview, Causes, & Risk Factors

Cellulitis is an infection of the skin and the layer of tissue under the skin.

What is going on in the body?

Cellulitis most often develops on the legs but can be seen on the face and on any other skin on the body. It tends to affect a fairly large area of skin. Cellulitis is usually due to an infection of the skin with bacteria, but it may also be caused by a fungus.

What are the causes and risks of the infection?

Cellulitis is usually caused by a break in the skin that becomes infected with bacteria or fungi. It can occur in wounds caused by injury and in surgical wounds. It can also occur when there is no obvious break in the skin.

Risk factors for cellulitis include the following:

Symptoms & Signs

What are the signs and symptoms of the infection?

Cellulitis may cause:

Diagnosis & Tests

How is the infection diagnosed?

Diagnosis of cellulitis begins with a medical history and physical examination. There is no single test that can confirm the diagnosis. In some cases, blood tests and special X-ray tests may be used to make sure a deeper, more serious infection is not present.

Prevention & Expectations

What can be done to prevent the infection?

Prevention of cellulitis starts with good hygiene. Any breaks in the skin, such as cuts, bites, or scratches, should be cleaned with soap and water before applying a bandage. The area should be kept clean until the skin has healed over.

People with diabetes need to be careful with wounds to their feet or legs. Diabetes causes nerve damage, known as neuropathy, which can result in a lack of feeling in the legs and feet. Because people with diabetes may not be aware of a foot injury, they should inspect their feet daily for any cuts or abnormal areas. Diabetes also causes poor circulation, which means wounds do not heal well. As a result, cellulitis is more difficult to treat in people with diabetes.

What are the long-term effects of the infection?

If cellulitis is not treated, it can get worse. Some cases can develop into deeper, more serious infections of the tissue under the skin. This can lead to serious effects, including loss of a limb and even death. Many cases of foot and leg amputation in people with diabetes start out as cellulitis.

What are the risks to others?

Cellulitis is not contagious and poses no risk to others.

Treatment & Monitoring

What are the treatments for the infection?

For mild, superficial infections, oral antibiotics, such as cephalexin or dicloxacillin, are often used. Over-the-counter pain medication, such as ibuprofen or acetaminophen, can be used as needed to relieve discomfort. For more severe infections, individuals may need intravenous (IV) antibiotics, such as oxacillin or nafcillin.

Cellulitis may get worse even with treatment, especially in people with diabetes. In these cases, more aggressive treatment may be needed. This may include surgery to remove dead skin or even bone.

What are the side effects of the treatments?

Antibiotics and over-the-counter pain medications may cause upset stomach, rash, or allergic reactions. Surgery may cause bleeding, new infections, or allergic reaction to anesthesia.

What happens after treatment for the infection?

In most cases, cellulitis goes away after treatment. If treatment is successful, people can usually return to normal activities.

How is the infection monitored?

The healthcare provider will examine the area of cellulitis regularly to assess healing. In some cases, special X-ray tests may be used if a deeper infection is suspected. Any new or worsening symptoms should be reported to the healthcare provider.