Most often cellulitis affects the dermis, the layer of the skin below the top layer (the epidermis) that contains connective tissue, blood vessels, oil and sweat glands, nerves, hair follicles, and other structures. Sometimes cellulitis penetrates below that layer and affects muscle tissue or even bone. (2,3) Cellulitis usually begins with a break in the skin, such as a scratch, cut, or other wound, says Edidiong C. Kaminska, MD, a Chicago-based dermatologist. “The skin appears swollen and red. It is typically painful and warm to touch,” Dr. Kaminska says, adding that the legs are affected most often, but cellulitis can develop anywhere on the body. Cellulitis usually responds well to oral antibiotics. Rarely, it can become life-threatening if it is left untreated or if complications are not adequately addressed. (2) During the physical exam, your doctor will note any redness, warmth, or swelling of the skin. The affected area will be checked for any buildup of pus (indicating an abscess) or swollen glands (lymph nodes). Your doctor may outline the edges of the reddened area with a pen and then check it a few days later to see if the redness has spread beyond the original borders. (2) If the suspected cellulitis is in your legs or feet, the doctor may look between your toes to see if there are breaks in the skin where the bacteria may be entering the body. (5) Lab tests that are likely to be ordered to determine if there is a bacterial infection include:
A blood cultureComplete blood count (CBC) panelA culture of any fluid or discharge from the affected area
If your infection is suspected to be a condition other than cellulitis, a biopsy or other types of tests may be done. (2)
Is Cellulitis Contagious?
Cellulitis is not typically spread from person to person. Generally, you get it from bacteria that live on the surface of your skin and penetrate into its deeper layers through a break in the skin. (6) Still, cellulitis can be contagious if there’s an open cut or wound in the infected area and fluid or pus from the wound is present. “These are Gram-positive bacteria, meaning that they have a thick cell wall,” Kaminska says. “Therefore, we typically prescribe medication that treats Gram-positive bacteria; the most common being antibiotics in the penicillin family, such as penicillin and ampicillin (Omnipen).” But, she adds, the decision may be made to prescribe antibiotics that cover both Gram-positive and Gram-negative bacteria, such as clindamycin (Cleocin HCI) or doxycycline (Vibramycin). Other antibiotics that may be prescribed include amoxicillin (Amoxil), dicloxacillin (Dycill), and cephalexin (Keflex). (5) Once you begin a course of antibiotics, it should not take long for your symptoms to improve. “Typically you will see a response within the first three days,” says Kaminska. “You should notice that the redness, swelling, and tenderness are starting to go down.” You should continue taking the antibiotics until you have taken all of the pills prescribed. It will usually take 7 to 10 days for cellulitis to go away, she says. But if you have a weakened immune system, you may be on antibiotics for a longer period. (4) Rachel Bystritsky, MD, an infectious disease specialist and assistant professor of medicine at the University of California in San Francisco, says MRSA can be a concern “particularly for cellulitis that involves an abscess or pus, or if there are other risk factors, like injection drug use.” To address it, “you would need to use agents that cover MRSA, such as trimethoprim sulfamethoxazole and clindamycin or doxycycline.” For people who are sick enough to be admitted to the hospital, vancomycin (Firvanq) is the primary medication prescribed, she adds. Practice guidelines recommend adding piperacillin-tazobactam (Zosyn) or meropenem (Merrem) to vancomycin if the infection is especially severe. (5)
Intravenous Antibiotics
“Typically, if a patient is not responding to oral antibiotics, and the cellulitis has symptoms that appear to be more involved and can’t be managed with antibiotics, such as high fever or low blood pressure — systemic signs of infection — then they get intravenous antibiotics,” says Kaminska. “That usually occurs in a hospital setting.” Intravenous treatment can include penicillin, cefazolin (Ancef), nafcillin (Unipen), and clindamycin, among other antibiotics. (9)
Surgery
In the case of abscess, gangrene (dead tissue), or other symptoms involving purulence, surgery is usually necessary to remove the infected tissue. For an abscess, typically an incision is made and the pus is drained out, says Kaminska. “Antibiotics are not going to treat that pocket of infection. It needs to be released.” Most times, surgery alone is used to address a purulent infection, without the addition of antibiotics, unless the person is also experiencing a systemic infection or a condition such as necrotizing fasciitis. (5). Also known as “flesh-eating disease,” necrotizing fasciitis is caused by a quickly spreading bacterial infection of the fascia (connective tissue) and surrounding soft tissue, causing the tissue to die. It can result in the loss of limbs or even death. To treat it, the dead tissue is surgically removed, and intravenous antibiotics are administered. Public health experts believe group A streptococcus (group A strep) bacteria are the most common cause of necrotizing fasciitis. (10). Orbital cellulitis, which affects the fat and muscle around the eye, is a serious condition that can result in blood poisoning (septicemia) or blindness. It may require surgery to relieve pressure around the eye or any abscesses that may be involved, as well as IV antibiotics. (11)
Wound Care
You may need special wound coverings or dressings to aid in the healing process after surgery for cellulitis. A wound care nurse or other medical professional will show you how to apply and change them, as well as how to keep your wound clean. (4)
Topical Antibiotics
Antibiotic ointments are rarely prescribed for the treatment of cellulitis, but in the case of a condition such as perianal streptococcal cellulitis, which affects the anus and rectum, a topical antibiotic, such as mupirocin (Bactroban) or retapamulin (Altabax), may be prescribed. (12,13)
Elevation
If you have cellulitis in a leg, you may be told to keep it elevated. “Lifting the leg for drainage is really key,” says Dr. Bystritsky. “It will help reduce the swelling and help your condition to improve.”
Treating Underlying Conditions
Treating any conditions that may have predisposed you to developing cellulitis, such as diabetes, cancer, HIV or AIDS, lymphedema, or peripheral vascular disease, may help to lower your risk of developing cellulitis again. Being overweight or obese are also associated with a greater risk for cellulitis, and losing some weight lowers that risk. (14) Bystritsky has additional advice for preventing a repeat episode of cellulitis: “Treat nail fungal infections or fungal infections in the webbing of the toes.” Fungal infections of the feet, known as athlete’s foot, typically cause redness, itching, scaling or flaking of the skin, cracks in the skin, and sometimes blisters. Athlete’s foot is highly treatable with over-the-counter antifungal creams, gels, lotions, sprays, and powders. Also, do what you can to keep your skin in good condition so that you can avoid breaks in the skin that will invite bacteria in and cause cellulitis. Good skin care includes:
Bathing regularly in warm — not hot — waterMoisturizing areas of dry skinUsing sunscreen when you spend time outsideInspecting your skin, especially the skin on your feet, daily for signs of irritationCleaning and bandaging any wounds immediately
