Cellulitis (sel-u-LIE-tis) is a common, potentially serious bacterial skin infection. Cellulitis appears as a swollen, red area of skin that feels hot and tender. It can spread rapidly to other parts of the body. Cellulitis isn’t usually spread from person to person.
Skin on lower legs is most commonly affected, though cellulitis can occur anywhere on your body or face. Cellulitis might affect only your skin’s surface. Or it might also affect tissues underlying your skin and can spread to your lymph nodes and bloodstream.
Left untreated, the spreading infection can rapidly turn life-threatening. It’s important to seek immediate medical attention if cellulitis symptoms occur.
Cellulitis occurs when bacteria, most commonly streptococcus and staphylococcus, enter through a crack or break in your skin. 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. Bacteria can also enter through areas of dry, flaky skin or swollen skin.
Possible signs and symptoms of cellulitis, which usually occur on one side of the body, include:
- Red area of skin that tends to expand
- Red spots
- Skin dimpling
When to see a doctor
It’s important to identify and treat cellulitis early because the condition can spread rapidly throughout your body.
Seek emergency care if:
- You have a red, swollen, tender rash or a rash that’s changing rapidly
- You have a fever
See your doctor, preferably that day, if:
- You have a rash that’s red, swollen, tender and warm — and it’s expanding — but without fever