Cellulitis is a common, potentially serious bacterial infection of the skin and tissues beneath the skin that appears as a swollen, red area of skin that feels hot and tender. Cellulitis might affect only the skin's surface or it might also affect deeper tissues (dermis and subcutaneous tissue) and can spread to the lymph nodes and bloodstream. It most commonly affects the skin on lower legs and it can spread rapidly to other parts of the body or face, but it is not usually spread from one person to another.


Cellulitis most commonly affects one of the legs, although symptoms can develop in any area of the body. It usually begins as a small area of tenderness, swelling and redness that spreads to adjacent skin. If the patient has Cellulitis, he may also find that blisters develop on the skin. Possible signs and symptoms include:

  • Red area of skin that tends to expand;
  • Swelling;
  • Tenderness;
  • Pain;
  • Warmth;
  • Fever;
  • Red spots;
  • Blisters;
  • Skin dimpling.

Cellulitis can make the patient feel generally unwell, causing symptoms that develop before, or in combination with, changes to the skin. These symptoms include:

  • Nausea;
  • Shivering;
  • Chills;
  • Sweats;
  • A general sense of feeling unwell.


The main bacteria responsible for Cellulitis are Streptococcus and Staphylococcus. However, other bacteria (for example, Hemophilus influenzae, Pneumococcus and Clostridium species) may cause Cellulitis as well. Cellulitis occurs when the particular bacteria enters through a crack or break in the skin. The bacteria is most likely to enter disrupted areas of skin, such as where the person has 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.


The bacteria that cause Cellulitis can spread rapidly, entering lymph nodes and the bloodstream. Recurrent episodes of Cellulitis may damage the lymphatic drainage system and cause chronic swelling of the affected limb. In rare cases, the infection can spread to the deep layer of tissue called the fascial lining. Flesh-eating strep (necrotizing fasciitis) is an example of a deep-layer infection. It represents an extreme emergency. Complications of Cellulitis can include blood poisoning, abscesses, necrotizing fasciitis and meningitis.

Risk Factors

Several factors can place the patient at greater risk of developing Cellulitis:

  • Injury;
  • Weakened immune system;
  • Skin conditions;
  • Chronic swelling of the arms or legs (Lymphedema);
  • History of Cellulitis;
  • Intravenous drug use;
  • Obesity.


In people with predisposing conditions or weakened immune systems, Cellulitis may not always be preventable. Otherwise, it can be prevented by proper hygiene, proper treating chronic edema, responsible care of wounds or cuts and keeping the skin moisturized. In other cases, microscopic breaks in the skin may not be apparent and infection may develop.