Cellulitis is a bacterial infection of the skin that can occur anywhere in the body. There are several distinct types of cellulitis. They include:

• Preseptal cellulitis. Infection of the eyelid and soft tissues around the eye socket, which causes redness and swelling of the eyelid. It commonly occurs after trauma to the eyelid or when an infection in the upper respiratory tract spreads to the eye. It occurs more frequently in children.
  
  
• Orbital cellulitis. Similar to preseptal cellulitis, it affects tissue around the eye socket. This type is often a complication of sinusitis (sinus infection), and occurs more often in children.
  
  
• Necrotizing cellulitis. A severe form of cellulitis characterized by death of infected tissue (necrosis). Some bacterial infections can cause small blood vessels in the infected area to clot, causing the tissue served by the vessels to die from a lack of blood. When this happens, the immune defenses (such as white blood cells and antibodies) cannot reach the dead tissue. The infection spreads rapidly and sometimes leads to death if not treated.
  
  
• Erysipelas. An acute superficial form of cellulitis that is usually caused by a group A streptococci bacteria infection. It is characterized by hot, red, swollen and sharply defined skin eruption.