Cellulitis

Reviewed/Revised Nov 2023
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What is cellulitis?

Cellulitis is a bacterial infection in your skin.

  • Cellulitis is a common skin infection that can spread quickly and be very serious

  • The infected area hurts and is red, warm, and swollen

  • Cellulitis is most common on your legs but can happen anywhere

  • If the infection reaches your bloodstream, it can be life threatening

What causes cellulitis?

Cellulitis is caused by germs (bacteria) that get into your skin. Bacteria are most likely to enter through small breaks in your skin from scrapes, punctures, surgery, burns, fungal infections, animal bites, and skin disorders. However, cellulitis can also occur in skin that is not obviously injured.

Cellulitis is often caused by Staphylococcus bacteria (staph infection). One type of staphylococcus that can cause cellulitis is known as MRSA (methicillin-resistant Staphylococcus aureus). MRSA is resistant to many antibiotics and can be hard to treat.

People with a weakened immune system are more likely to get an infection that causes cellulitis.

People have a higher risk of getting cellulitis repeatedly if they have:

What are the symptoms of cellulitis?

  • Skin redness, swelling, warmth, and pain

  • Sometimes blisters with yellow fluid

  • Sometimes fever and swollen lymph nodes (swollen glands)

Cellulitis usually starts as a small, red patch that's slightly sore. The infected area can get larger quickly. In a couple of days, it could spread from a spot the size of a quarter on your calf to cover your entire lower leg.

If the infection gets into the blood stream, you can have high fever, low blood pressure, and shut down of some of your organs (sepsis).

How can doctors tell if I have cellulitis?

Doctors diagnose cellulitis based on how your skin looks. There are no tests to tell for sure. However, doctors may do tests such as an ultrasound to make sure the redness and swelling in your leg isn't because of a blood clot.

See a doctor immediately if an area on your skin is red, swollen, and painful.

How do doctors treat cellulitis?

  • Antibiotics to kill the bacteria

  • Usually you take the antibiotics by mouth but sometimes, when there is serious infection, by vein (IV) in the hospital

  • If you have cellulitis in your leg, doctors will ask you to elevate it

How can I prevent cellulitis?

  • Keep skin wounds clean, cover them with a bandage, and apply an antibiotic cream for protection

  • Treat fungal foot infections (such as athlete’s foot) and other skin conditions to help heal any breaks in the skin

  • If you have diabetes or poor circulation, examine your feet every day, use a moisturizer, and avoid injury by wearing proper shoes

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