The skin is covered with bacteria that are known as commensal organisms. Normally, the skin is able to keep these bacteria from penetrating past the outer layers, thus preventing infection. Sometimes bacteria can get under the skin, however, causing a potentially dangerous infection known as cellulitis.
Causes
Cellulitis is the result of bacterial infections in the deeper layers of the skin, SkinSight explains. In general, cellulitis is caused by Streptococcus or Staphylcoccus bacteria. These bacteria are able to get into the lower layers of the skin by penetrating through small cracks or fissures in the skin's outer layers. Once the bacteria have gotten past the top layers of the skin they can spread easily to the inner skin layers.
Symptoms
Cellulitis can cause redness, swelling and tenderness of the affected part of the body, according to the Mayo Clinic. The affected skin may also feel warm to the touch and be painful. Patients may also develop a fever as well as swelling of their lymph nodes. As the infection progresses, small red spots can appear on the swollen area; these spots may eventually burst.
Risk Factors
Cellulitis most commonly occurs in the legs, according to the Merck Manual. Patients with any sort of wound, be it a cut, puncture wound or burn can develop cellulitis. Patients with a weakened immune system and diabetes are also at a greater risk of developing cellulitis. Other skin disorders such as athlete's foot or eczema can increase a patient's risk of developing cellulitis, as can chronic swelling of the limbs. Use of intravenous drugs can also predispose a patient to developing cellulitis.
Complications
The primary danger of cellulitis is that the bacteria can rapidly spread throughout other tissues in the body. If the bacteria get into the bloodstream, sepsis can occur, which can be life threatening. Chronic cellulitis can also damage the lymphatic system, according to the Mayo Clinic, which can lead to chronic swelling of the affected area. If the bacteria progresses to the tissue under the skin it can lead to a dangerous necrotizing infection, which is sometimes termed flesh-eating disease.
Diagnosis and Treatment
Diagnosis of cellulitis is usually done based on the appearance of the affected skin, according to the Merck Manual. Physicians may culture bacteria from the wound in order to determine the type of bacteria causing the infection. Cellulitis can be treated with broad-sepctrum antibiotics, such as cephalexin and dicloxacillin. These antibiotics can be given orally or intravenously.
