What is cellulitis?Cellulitis is a potentially serious bacterial infection of your skin. It appears as a swollen, red area of skin that feels hot and tender, and it may spread rapidly. Cellulitis is a common infection of the skin and the soft tissues underneath the skin. It occurs when bacteria invade broken or normal skin and start to spread just under the skin or in the skin itself. This results in infection and inflammation. Inflammation is a process in which the body reacts to the bacteria. Inflammation may cause
swelling, redness, pain, or warmth.
Skin on the lower legs or face is most commonly affected by this infection, though cellulitis can occur on any part of your skin. The infection may only be superficial, but it may also affect the tissues underlying your skin and can spread to your lymph nodes and bloodstream. Unlike impetigo, which is a very superficial skin infection, cellulitis refers to an infection involving the skin's deeper layers; the dermis and subcutaneous tissue. The main bacteria involved in cellulitis is Staphylococcus ("staph"), the same bacteria that causes many cases of impetigo. Occasionally, other bacteria may cause cellulitis as well. Left untreated, the spreading bacterial infection may rapidly turn into a life-threatening condition. That's why it's important to recognize the signs and symptoms of cellulitis and to seek immediate medical attention if they occur.
Many different types of bacteria can cause cellulitis. However, most cases are caused by Streptococcus pyogenes (strep) or Staphylococcus aureus (staph). Other types of bacteria can cause infection after certain types of skin injuries, such as animal bites, puncture wounds through wet shoes, and wounds exposed to freshwater lakes, aquariums, or swimming pools.