Cellulitis is a common, potentially serious bacterial skin infection. Cellulitis appears as a swollen, red area of skin that feels hot and tender, and it may spread rapidly.
Skin on lower legs is most commonly affected, though cellulitis can occur anywhere on your body or face. Cellulitis may affect only your skin's surface, or cellulitis may also affect tissues underlying your skin and can spread to your lymph nodes and bloodstream.
Left untreated, the spreading infection may rapidly turn life-threatening. That's why it's important to seek immediate medical attention if cellulitis symptoms occur.
Signs and Symptoms
Possible signs and symptoms of cellulitis include:
Redness
Swelling
Tenderness
Pain
Warmth
Fever
The changes in your skin may be accompanied by a fever. Over time, the area of redness tends to expand. Small red spots may appear on top of the reddened skin, and less commonly, small blisters may form and burst.
Etiology
Cellulitis occurs when one or more types of bacteria enter through a crack or break in your skin. The two most common types of bacteria that are causes of cellulitis are streptococcus and staphylococcus. The incidence of a more serious staphylococcus infection called methicillin-resistant Staphylococcus aureus (MRSA) is increasing.
Although cellulitis can occur anywhere on your body, the most common location is the lower leg. Bacteria is most likely to enter disrupted areas of skin, such as where you've had recent surgery, cuts, puncture wounds, an ulcer, athlete's foot or dermatitis.
Certain types of insect or spider bites also can transmit the bacteria that start the infection. Areas of dry, flaky skin also can be an entry point for bacteria, as can swollen skin.
Risk Factors
Several factors can place you at greater risk of developing cellulitis:
Known injury. Any cut, fracture, burn or even a scrape increases your risk of cellulitis because the injury gives bacteria an entry point.
Weakened immune system. Conditions that