What is adult cellulitis?

Adult cellulitis is bacterial infection of the skin and the deeper tissues beneath the skin. It most often develops in the legs, but it can occur in any part of the body.

Cellulitis is not contagious.

Who gets adult cellulitis?

Anyone with a cut, sore, insect bite, scrape, or other open wound can get cellulitis. Injuries in water or dirty areas can make someone especially vulnerable to the infection.

Additional risk factors for cellulitis include:

  • Skin infections such as impetigo, scabies, or athlete's foot
  • Having had liposuction to remove excess fat
  • Skin inflammations such as eczema
  • Having injected illegal drugs through the skin
  • Skin ulcers
  • Fragile skin
  • Exposure to MRSA (Methicillin-resistant Staphylococcus aureus)
  • Edema (fluid buildup) in the arms or legs
  • Dog or cat bite

Some people, usually those with a weakened immune system due to illness or diabetes, can get cellulitis without a cut or sore. Elderly people and people with poor circulation, called chronic venous insufficiency, are also at higher risk of cellulitis.

What causes adult cellulitis?

Cellulitis can be caused by many different bacteria. The most common cause is infection by the Streptococcus bacteria. It can also be caused by Staphylococcus or Pasteurella multocida in the case of dog or cat bites. About 25 percent of cellulitis cases are caused by MRSA.

These bacteria enter the skin through cuts or wounds or fragile or swollen skin.

What are the symptoms of adult cellulitis?

A person with cellulitis may notice symptoms in the affected area before he or she feels ill.

The most common symptoms of cellulitis are pain, tenderness, and redness in the affected area, as the body attempts to fight off the bacterial infection. Other symptoms include:

  • Swollen skin
  • Skin that is hot to the touch
  • Skin that has a "pitted" look
  • Fluid-filled blisters
  • Discharge from the skin
  • Fever
  • Increased pulse rate
  • Swollen lymph nodes near the affected area

If you notice any of these symptoms, you should see your doctor immediately.

How is adult cellulitis diagnosed?

Your doctor can usually diagnose cellulitis based on your symptoms and a visual inspection of your skin. He or she may also want to take a blood or pus sample from the area to confirm the diagnosis.

If you have frequent cellulitis infections, your physician may also want to run a glucose check to see if you have diabetes. This condition could be causing the cellulitis as well as other health problems.

How is adult cellulitis treated?

Adult cellulitis is usually treated with antibiotics such as dicloxacillin or cephalexin. In many cases, these can be taken by mouth.

For more serious cases of adult cellulitis, the doctor may prescribe intravenous antibiotics. This may be especially necessary for patients with high fevers. These can be administered in a hospital or the doctor's office.

Warm compresses or cool dressings can be applied to the affected are to reduce symptoms and irritation. Elevating affected areas can also help reduce swelling.

What is the prognosis for adult cellulitis?

If diagnosed early, adult cellulitis can be completely treated with antibiotics, usually a 10-day course.

It is very important to take cellulitis seriously and get prompt treatment. It can quickly progress and lead to more serious conditions such as sepsis (blood infection) and necrotizing fasciitis, (flesh-eating disease). See your doctor as soon as possible if you notice any symptoms of cellulitis.


  • Adult Cellulitis
  • Lutomski DM, Trott AT, Runyon JM, Miyagawa CI, Staneck JL, Rivera JO. Microbiology of adult cellulitis. J Fam Pract. 1988;26(1):45-8.

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This information is provided by the Cleveland Clinic and is not intended to replace the medical advice of your doctor or health care provider. Please consult your health care provider for advice about a specific medical condition. This document was last reviewed on: 7/24/2014...#15071