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Cellulitis: Who gets and causes

Who gets cellulitis?

Cellulitis is common, and anyone can get this infection. It’s estimated that 14.5 million cases of cellulitis are diagnosed in the United States each year.

The number of people who get cellulitis is expected to grow. That’s because more people than ever have an increased risk because they are:

  • Middle-aged or older

  • Overweight or obese

  • Diabetic, especially if the diabetes is poorly controlled

All of these decrease the body’s ability to fight an infection.

Bandages help keep bacteria out

Keeping wounds clean and covered can reduce the risk of getting cellulitis.

Bandages on wounds help keep bacteria out

What causes cellulitis?

Bacteria cause cellulitis. Streptococcus (strep) and Staphylococcus (staph) are responsible for most cases of cellulitis. MRSA (methicillin-resistant Staph aureus) and other bacteria can also cause cellulitis.

Many of these bacteria live on our skin without causing a problem. However, once they get inside the body, they become harmful.

The bacteria may get inside the body when we injure our skin. An injury can be obvious, such as an open sore or severe burn. Cuts, scratches, and abrasions also provide a way for the bacteria to get inside.

Cracks in the skin offer another way for the bacteria to get in. People who have eczema, athlete’s foot, or very dry skin often have deep cracks in their skin. Bacteria can get into the body through these cracks.

Of course, not everyone who has a skin injury or deep cracks will get cellulitis. The body’s immune system works hard to destroy the harmful bacteria.

What increases the risk of getting cellulitis?

If any of the following apply to you, you have a higher risk.

Diseases and treatments: The following can increase your risk because they either make it easier for bacteria to get inside your body or harder for your body to fight the bacteria:

  • Athlete’s foot

  • Atopic dermatitis (eczema)

  • Cellulitis (already had)

  • Chemotherapy (undergoing)

  • Corticosteroids (taking)

  • Diabetes (poorly controlled)

  • HIV or AIDS

  • Kidney disease (long-term)

  • Liver disease (long-term)

  • Lymphedema

  • Medicine taken to prevent rejecting a transplanted organ

  • Poor circulation and a related condition like stasis dermatitis or a leg ulcer

  • Surgery (recent)

Athlete’s foot can cause tiny cracks in the skin. When bacteria get into the body through these cracks, cellulitis tends to appear in the calf. Treating athlete’s foot early can prevent this.

Athlete's foot can cause tiny cracks in the skin

People who frequently injure their skin: Research shows that the following people, who tend to have more skin injuries, often have a higher risk of getting cellulitis:

  • Athletes

  • Children

  • Drug abusers who use needles to inject drugs

  • Military personnel on active duty

  • Prisoners

  • Residents in a long-term care facility

Getty Images

Al-Niaimi F, Neil Cox N. “Cellulitis and lymphedema: A vicious cycle.” J of Lymphoedema.” 2009;4(2):38-42.

Habif TP, Campbell, JL, et al. “Cellulitis.” In: Dermatology DDxDeck. Mosby Elsevier, China, 2006: Card#47.

Hapern AV and Heymann WR. ““Bacterial diseases.” In: Bolognia JL, et al. Dermatology. (second edition). Mosby Elsevier, Spain, 2008:1084.

Raff AB, Kroshinsky D. “Cellulitis: A review.” JAMA. 2016;316(3):325-337.

Strazzula L, Cotliar J, et al. “Inpatient dermatology consultation aids diagnosis of cellulitis among hospitalized patients: A multi-institutional analysis.” J Am Acad Dermatol. 2015;73(1):70-5.