Cellulitis is an infection of the deeper skin tissue, most often caused by the types of bacteria called Streptococcus
, or (in children under 2 years old, Haemophilus
These bacteria invade the skin through small cracks (fissures) in the skin, causing the sudden appearance of skin redness, swelling, and the sensation of heat. Cellulitis often occurs with fever and chills.
If the infection goes untreated too long, cellulitis can result in pockets of pus (abscesses) or the bacteria can spread into the bloodstream (bacteremia). However, most cellulitis heals after treatment with antibiotics.
Who's At Risk
Cellulitis can occur in people of all ages, all races, and of both sexes.
In children, cellulitis usually develops 1–2 days following a wound to the skin. Other factors that can increase the risk of developing cellulitis include:
- Long-term (chronic) lower leg swelling (edema)
- Athlete's foot (tinea pedis)
- Bites from insects, animals, or other humans
- Poor circulation in the legs (peripheral vascular disease)
- Weakened immune systems due to illness or medication
- Injected (intravenous) drug abuse or alcoholism
Signs and Symptoms
The most common locations for cellulitis include:
- Lower legs
- Arms or hands
Cellulitis initially appears as pink-to-red, slightly inflamed skin. The affected skin quickly becomes deeper red, swollen, warm, and tender, and the affected area increases in size as the infection spreads. Occasionally, red streaks may radiate outward from the cellulitis. Blisters or pus-filled pockets (pustules) may be present.
Cellulitis may occur with swollen lymph glands. Fever and chills are common.
There are no self-care treatments for cellulitis. See your child's physician immediately or take the child to the emergency room. If an arm or leg is involved, you can raise (elevate) the affected body part to reduce or prevent swelling.
When to Seek Medical Care
If your child develops a tender, red, warm, enlarging area on the skin, see a doctor as soon as possible. If your child also has fever and chills, or if the area is on the child's face, you should go to the emergency room.
If your child is currently being treated for a skin infection that has not improved after 2–3 days of antibiotics, return to the child's doctor.
Community-associated methicillin-resistant Staphylococcus aureus
(CA-MRSA) is a strain of "staph" bacteria resistant to antibiotics in the penicillin family, which have been the cornerstone of antibiotic therapy for staph and skin infections for decades. CA-MRSA previously infected only small segments of the population, such as health care workers and persons using injection drugs. However, CA-MRSA is now a common cause of skin infections in the general population. While CA-MRSA bacteria are resistant to penicillin and penicillin-related antibiotics, most staph infections with CA-MRSA can be easily treated by health care practitioners using local skin care and commonly available non-penicillin-family antibiotics. Rarely, CA-MRSA can cause the serious skin and soft tissue (deeper) infection cellulitis, which requires intravenous (IV) antibiotics in most people to clear the infection. If you think your child may have a cellulitis, contact his or her doctor immediately.
Treatments Your Physician May Prescribe
Although your child's doctor may easily diagnose cellulitis, he or she may wish to order other procedures such as blood tests or a skin biopsy. In addition, the doctor may perform a bacterial culture to find out what type of bacteria may be causing the cellulitis.
In the culture procedure, the doctor will:
- Penetrate any blisters or pus-filled pockets with a needle, scalpel, or small blade (lancet).
- Rub a sterile cotton swab across the skin to collect the sample.
- Send the specimen away to a laboratory for evaluation.
If there are many bacteria present in the sample, the laboratory will usually have some idea of what type it is within 48–72 hours. However, the culture may take a full week or more to produce final results. In addition to identifying the type of bacteria that is causing the cellulitis, the laboratory usually performs a test (antibiotic sensitivity testing) to determine which antibiotics will be most effective in killing off the bacteria.
While waiting for the results from the bacterial culture, the doctor will probably want to start your child on an antibiotic to fight the most common bacteria that cause cellulitis. Once the final culture results have returned, the physician may change the antibiotic, especially if your child is not improving on the one initially prescribed.
Mild cases of cellulitis in otherwise healthy people can be treated on an outpatient basis with oral antibiotic pills or syrups. Common oral antibiotics that are used to treat cellulitis include:
However, ill-appearing children who have other illnesses or those who have cellulitis of the face may need to be admitted to the hospital for observation and so they can receive injected (intravenous) antibiotics. Common intravenous antibiotics used in hospitals to treat cellulitis include:
If your child's doctor prescribes antibiotics, be sure the child takes the full course of treatment. In addition to prescribing antibiotics, the doctor will likely want to make sure that your child has no other medical problems.
Bolognia, Jean L., ed. Dermatology
, pp.1123-1124. New York: Mosby, 2003.
Freedberg, Irwin M., ed. Fitzpatrick's Dermatology in General Medicine
ed, pp. 1845, 1848, 1883. New York: McGraw-Hill, 2003.