Cellulitis is an infection in the deepest layers of the skin. It typically begins when an injury isn't cleaned well, allowing bacteria to get inside and multiply. The area usually becomes swollen and red. If not treated early, the infection can spread throughout the body with serious and even fatal consequences. Cellulitis should not be confused with cellulite, which is a dimpling in the skin caused by deep layers of fat.
Signs and Symptoms
Skin that is infected often becomes inflamed — meaning that it swells up — and feels tight. It may be tender and hurt when it is touched. The skin also typically feels warm, both to the person who has the infection and to someone touching the area. The infected area often looks glossy, as the skin is pulled tight, and turns red or develops a rash of small red dots, which can spread as the infection advances. If the lymphatic system becomes infected, red lines or streaks may appear on the skin.
Someone with cellulitis may experience other symptoms that don't seem directly related to the infected area. A fever and chills often accompany any type of infection, as do muscle aches. As the infection advances, the lymph nodes may become swollen as well. Cellulitis often spreads very quickly, so these symptoms may develop and spread over just a day or two.
Causes
Cellulitis most often occurs when a cut in the skin is not cleaned completely, or if it is not covered and cared for properly. The bacteria that is often present on normal skin cells or in the environment can then get inside, invading the lowest layers of the skin. The most common bacteria that cause infections of this type are Streptococcus (strep) and Staphylococcus (staph).
This type of bacterial infection is not usually contagious because it affects the deeper layers of the skin. A person with an open wound can pick up the bacteria from another person, however, even if that bacteria is not making the other person sick.
Diagnosis
Anyone who has an injury that appears red and swollen should see a healthcare professional immediately. He or she will examine the area, and may take a sample to identify the specific bacteria causing the infection. The medical provider may also run a blood test to rule out other conditions, like deep vein thrombosis or gout, that have similar symptoms.
Risk Factors
While anyone who has a cut, puncture, or burn may develop cellulitis if the wound is not cared for correctly, people who are obese may be more vulnerable to infection. People with diabetes, who are more likely to experience ulcers and other open wounds on the legs and feet, are also at greater risk for infection. People with a weak immune system, such as those with HIV/AIDS or leukemia, are also less likely to be able to fight off the initial infection, leaving them open to more serious complications.
Any condition that can lead to open sores or punctures in the skin can also add to a person's risk of developing this type of infection. People who need regular intravenous (IV) therapy or who are IV drug users are at risk. Anyone with chicken pox may be vulnerable, if the pocks are scratched, as may those with chronic lymphedema, in which the skin swells and cracks. Even a seemingly minor condition, like athlete's foot, can be a risk factor when it leads to breaks in the skin. Spider bites, particularly those from the brown recluse, may cause immediate infection.
Treatment
Cellulitis is treated with antibiotics to kill the bacteria causing the infection. Depending on the type of bacteria and how advanced the infection is, the medication may be given by mouth or by IV. Serious cases, in which the infection has spread throughout the skin or into other parts of the body, may require hospitalization. In less serious cases, oral antibiotics usually work in one to two weeks.
Pain relievers and anti-inflammatory medications can be taken to relieve the pain and swelling associated with this condition. Cool compresses placed over the area can also help, as can keeping the affected body part elevated so that the swelling doesn't get worse.
Prognosis
When caught early, cellulitis can be treated relatively easily and often with few long-term problems. If left untreated, however, this infection can spread and kill the sufferer in a relatively short period of time. People who have diabetes, fungal infections, or another condition that can damage the skin are more likely to develop an infection multiple times, as are people who don't get treatment early.
Complications
This skin infection spreads quickly and can lead to more serious complications, including endocarditis, an inflammation of the heart, and sepsis, in which the entire body becomes inflamed. Septic shock, a form of extremely severe sepsis where the blood pressure drops and organ systems begin failing, can also occur. These conditions are extremely serious and can be fatal.
Cellulitis can also cause serious damage to the body's tissues, including gangrene and necrotizing fasciitis, also known as "flesh-eating bacteria disease." Necrotizing fasciitis spreads extremely quickly, and requires immediate antibiotic treatment and the removal of all infected tissues. Either condition can lead to amputations.
If the infection advances to the lymph nodes, they can spread the bacteria to other parts of the body. They may need to be drained to prevent the infection from penetrating deeper into the tissues. The lymph nodes may also be damaged, causing chronic swelling in the body part.
When the infection begins in the face or head, it can spread to the eyes, causing orbital or pre-septum cellulitis. Orbital infections cause the eyeball to swell up, and can lead to problems with eye movement; if not treated, it can cause blindness. Pre-septum infections only affect the eyelid and skin around the eyes, but can spread to the eye itself. In serious cases, cellulitis in the face may lead to bacterial meningitis, an infection of the membranes around the brain and spinal cord, which is a potentially life threatening condition.
Prevention
The easiest way to prevent cellulitis is to clean any cuts or abrasions immediately, apply an antibiotic ointment, and keep all wounds covered and protected until they heal. The injured person should rewash the injury daily and reapply the antibiotic unless otherwise advised by a medical professional. Chicken pox or injuries that have scabbed over should not be picked at, as it risks reopening the wound. An individual who suspects he or she has been bitten by a poisonous spider should seek medical attention immediately.
People with diabetes should check their legs and feet for injuries and athlete's foot regularly, and care should be taken when cutting the toenails to prevent small, unnoticed cuts. Those with suppressed immune systems should be especially careful to avoid injury whenever possible, and treat any wounds immediately. Keeping the skin moisturized and healthy can also help prevent cracks and other damage that can allow bacteria to enter.
