Definition and Overview

Cellulitis is a potentially serious skin infection commonly caused by staphylococci and streptococci bacteria. It usually presents as a rapidly spreading infection characterised by pain, warmth, and inflammation. Unlike other skin infections that only affect the epidermis or the outermost layer of skin, cellulitis can also involve the skin’s deeper layers, namely the dermis and subcutaneous tissue, as well as the lymph nodes. In severe cases, the infection can spread to the bloodstream, resulting in sepsis that triggers widespread inflammation and blood clotting.

Cellulitis can develop anywhere in the body but its most common site is the lower part of the leg (particularly the shinbone and foot) followed by the neck and head. The infection, which usually develops in pus-filled pockets and open wounds, spreads rapidly because the offending bacteria produce enzymes that hinder the tissue’s ability to confine the infection.

Cellulitis is not contagious and is often successfully treated with two- to three-week antibiotic therapy. However, if the infection spreads to the deeper layers of the skin before being diagnosed and treated, patients are more likely to develop life-threatening complications that require a more aggressive treatment.

Causes of Condition

Because the skin and outer tissue are in constant contact with the environment, many types of bacteria reside on the hair, skin, and even on the inner surface of the mouth and nose without causing damage to healthy individuals. However, they can cause an infection that has the potential to become life-threatening if they get inside the body of a person with the following risk factors:

  • Compromised immune system - People with a compromised or weakened immune system, such as those who have diabetes or undergoing chemotherapy, are generally more susceptible to infections.

  • History of cellulitis

  • Intravenous drug use

  • Lymphedema - Chronic swelling of arms or legs that makes the skin more vulnerable to bacterial infection

  • Obesity

  • Certain skin disorders, such as dermatitis

  • Fungal or viral skin infection

Key Symptoms

Symptoms of cellulitis usually develop within 24 hours after a wound has been infected. The symptoms generally get worse quickly. Initially, the affected skin becomes red, swollen, and painful. As the infection spreads to surrounding tissues, the following symptoms will develop:

  • Abscess with pus formation

  • Fever

  • Glossy, tight, or overly stretched skin

  • Small pimples or blisters on the skin

If the condition is not treated promptly, the bacteria can affect deeper layers of the skin and may cause more serious signs and symptoms, including chills, shaking, fatigue, dizziness, muscle pain, malaise, blistering, and red streaks. If bacteria reach the bloodstream and cause blood poisoning, the patient will experience high fever, fast heart rate, confusion, altered mental state, slurred speech, and difficulty breathing.

Who to See and Types of Treatments Available

Patients showing symptoms of cellulitis can consult a general practitioner (GP) or their family doctor for assessment and treatment. A physical examination of the affected area and analysing a swab sample from the open wound in a laboratory are usually enough to diagnose the condition and identify the type of bacteria that caused it.

Cellulitis is often successfully treated with pain relievers and antibiotic therapy, which can last for two to three weeks depending on the severity of the condition. It is uncommon for patients to require further treatment aside from rare cases in which the following complications occur:

  • Blood infection and sepsis - Patients suffering from sepsis are treated in an intensive care unit (ICU) where they receive support for any affected body functions while their infection is being treated with antibiotics delivered through an IV (intravenously). They have a good chance of full recovery with no lasting problems or complications if they are diagnosed and treated promptly.

  • Spread of infection to other parts of the body - Serious cases of infection can spread to the bones, muscles, and major organs such as the lungs, heart, and brain.

  • Long-term damage to the lymph drainage - In some cases, swelling of tissue remains unresolved even after aggressive antibiotic treatment. This can lead to permanent swelling and skin tissue damage.


The risk of cellulitis can be significantly reduced with the following:

  • Washing open wounds using soap and water significantly reduces the risk of bacterial infection. It is important to ensure that the wounds are free from dirt and debris before they are covered with gauze or bandage.

  • Drink at least eight glasses of water every day as this helps in flushing out harmful organisms and toxins from the body that may cause cellulitis and other types of infections.

  • The use of protective cream on a regular basis prevents the cracking or peeling of skin.

  • Treat superficial skin infections, such as athlete’s foot, promptly.

  • Inspect legs daily for signs of injury.

  • Maintain a healthy weight. Being obese or overweight increases the risk of cellulitis.

  • If swelling, redness, or pain begins to develop, consult a doctor right away for treatment.

  • Eat a well-balanced diet consisting of fruits and vegetables; such diet can help speed up the body’s natural wound healing process and bolster the immune system.


  • Barbara Woodward Lips Patient Education Center. Cellulitis. Rochester, Minn.: Mayo Foundation for Medical Education and Research; 2009.

  • Skin care. American Diabetes Association.

Share This Information: