Cellulitis is a common skin infection caused by bacteria.
Skin infection - bacterial
Causes, incidence, and risk factors
Staphylococcus and streptococcus bacteria are the most common causes of cellulitis.
The skin normally has many types of bacteria living on it. When there is a break in the skin, however, bacteria can enter the body and cause infection and inflammation. The skin tissues in the infected area become red, hot, irritated, and painful.
Risk factors for cellulitis include:
- Cracks or peeling skin between the toes
- History of peripheral vascular disease
- Injury or trauma with a break in the skin (skin wounds)
- Insect bites and stings, animal bites, or human bites
- Ulcers from diabetes or a blockage in the blood supply (ischemia)
- Use of corticosteroid medications or medications that suppress the immune system
- Wound from a recent surgery
- Signs of infection:
- Pain or tenderness in the area with the rash or sore
- Skin redness or inflammation that increases in size as the infection spreads
- Skin sore or rash (macule):
- Comes on suddenly
- Grows quickly in the first 24 hours
- Usually has sharp borders
- Tight, glossy, "stretched" appearance of the skin
- Warmth over the area of redness
Other symptoms that can occur with this disease:
- Hair loss at the site of infection
- Joint stiffness caused by swelling of the tissue over the joint
- Nausea and vomiting
Signs and tests
During a physical examination, the doctor may find:
- Redness, warmth, and swelling of the skin
- Swelling and drainage if the infection is around a skin wound
- Swollen glands (lymph nodes) near the cellulitis
Your health care provider may mark the edges of the redness with a pen, to see if the redness goes past the marked border over the next several days.
Tests that may be used:
Cellulitis treatment may require a hospital stay if:
- You are very sick (very high temperature, blood pressure problems, nausea and vomiting that does not go away)
- You have been on antibiotics and the infection is getting worse
- Your immune system is not working well (due to cancer, HIV)
- You have an infection around your eyes
Most of the time, treatment with oral antibiotics and close follow-up is enough. Treatment is focused on controlling the infection and preventing complications.
You may receive antibiotics to control the infection, and analgesics to control pain.
Raise the infected area higher than your heart to reduce swelling. Rest until your symptoms improve.
It is possible to be cured with 7 - 10 days of treatment. Cellulitis may be more severe in people with chronic diseases and those who are more prone to infection because their immune system is not working properly (immunosuppressed).
People with fungal infections of the feet may have cellulitis that keeps coming back. The cracks in the skin offer an opening for bacteria to get inside.
Calling your health care provider
Call your health care provider if:
- You have symptoms of cellulitis
- You are being treated for cellulitis and you develop new symptoms, such as persistent fever, drowsiness, lethargy, blistering over the cellulitis, or red streaks that spread
Seek medical attention immediately if the cellulitis is on your face.
Protect your skin by:
- Keeping your skin moist with lotions or ointments to prevent cracking
- Wearing shoes that fit well and provide enough room for your feet
- Learning how to trim your nails to avoid harming the skin around them
- Wearing appropriate protective equipment when participating in work or sports
Whenever you have a break in the skin:
- Clean the break carefully with soap and water
- Cover with a bandage and change it every day until a scab forms
- Watch for redness, pain, drainage, or other signs of infection
Stevens DL, Bisno AL, Chambers BF, Everett ED, Dellinger P, Goldstein EJ, et al. Infectious Diseases Society of America. Practice guidelines for the diagnosis and management of skin and soft-tissue infections. Clin Infect Dis. 2005;41:1373-1406.
Abrahamian FM, Talan DA, Moran GJ. Management of skin and soft-tissue infections in the emergency department. Infect Dis Clin North Am. 2008;22:89-116.
Reviewed By: Michael Lehrer, MD, Department of Dermatology, University of Pennsylvania Medical Center, Philadelphia, PA. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.