False about cellulitis
It is spreading inflammation of subcutaneous and fascial planes.  
 Infection may follow a small scratch or wound or incision.

Causative Agents: Commonly due to Streptococcus pyogenes and other Gram +ve organisms.
Sequelae

Infection can get localized to form a pyogenic abscess. 
Infection can spread to cause bacteraemia, septicaemia, pyaemia.    
Often infection can lead to local gangrene.
Abscess if any should be managed conservatively
Causes SIRS
Infection of subcutaneous tissue
Caused by strep. pyogenes