- Cellulitis causes redness, warmth, pain, swelling, and sometimes fever, usually after bacteria enter through damaged skin.
- Treatment typically involves oral antibiotics, while severe cases may require hospitalization and intravenous medication.
- Go to the ER if cellulitis affects the face or eye area, spreads quickly, or causes high fever or severe pain.
Cellulitis is a bacterial infection, usually caused by Streptococcus or Staphylococcus bacteria, that affects the deep dermis and subcutaneous tissue. It can cause redness, pain, swelling, warmth, and fever, and most often develops after bacteria enter the skin through a cut, scrape, insect bite, or other injury.
Cellulitis is different from cellulite, which is the harmless dimpled appearance of the skin. Without prompt treatment, cellulitis can lead to serious complications, including sepsis, especially if the infection spreads.
Cellulitis treatment usually involves oral antibiotics, although severe infections may require hospitalization and intravenous medication. Diagnosis is generally based on a physical exam and medical history, while recovery often takes 5 to 14 days.
Cellulitis symptoms
The main symptoms of cellulitis include:
- Pain in the affected area
- A large red or inflamed area with poorly defined borders
- Fever above 100.4°F (38°C)
- Swelling, sometimes with pus
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Swollen lymph nodes near the affected area
Cellulitis most commonly affects the legs, feet, face, or the area around the eyes, although it can occur anywhere on the body.
Anyone with symptoms of cellulitis should see a primary care provider, dermatologist, or go to an emergency department for evaluation. An infectious disease specialist may also be involved in more severe or complicated cases.
Confirming a diagnosis
Cellulitis is usually diagnosed by a healthcare provider based on a physical examination of the affected skin. The provider will also ask about the person's medical history and any recent cuts, wounds, bites, or other skin injuries.
According to the CDC, cellulitis is usually diagnosed by examining the affected skin, and blood or other laboratory tests are not normally needed. However, a healthcare provider may order blood tests or blood cultures if the infection is severe or has caused symptoms throughout the body.
If pus or an open wound is present, a sample may be collected for testing to identify the bacteria causing the infection. A skin biopsy may be considered if the diagnosis is unclear or another skin condition is suspected.
These evaluations can help distinguish cellulitis from other conditions with similar symptoms, including erysipelas.
Erysipelas vs cellulitis
The main difference between cellulitis and erysipelas is the depth of the infection. Cellulitis affects the deeper layers of the skin, while erysipelas develops closer to the skin's surface.
Some differences that may help distinguish these conditions include:
A healthcare provider should examine the affected area because cellulitis and erysipelas can cause very similar symptoms. The diagnosis is usually based on the appearance of the skin, although tests may be ordered if the infection is severe or the diagnosis is unclear.
Possible causes
The main causes of cellulitis include:
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Cuts, scrapes, or other skin injuries
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Burns
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Surgical wounds
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Insect bites
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Animal bites
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Cracks between the toes
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Intravenous needle punctures
These conditions can damage the skin's natural protective barrier. This allows bacteria from the Staphylococcus or Streptococcus groups to enter the deeper layers of the skin or subcutaneous tissue and cause an infection.
People with weakened immune systems, diabetes mellitus, lymphedema, obesity, peripheral artery disease, or chronic venous insufficiency have a higher risk of developing cellulitis.
Is cellulitis contagious?
Cellulitis is not usually contagious and does not spread easily from person to person.
However, the bacteria that cause cellulitis can spread through direct contact with an infected wound or drainage. People with cuts, open wounds, or skin conditions such as dermatitis may be at higher risk if the bacteria enter through damaged skin.
Cellulitis treatment
Treatment for cellulitis usually involves oral antibiotics prescribed by a healthcare provider. According to the CDC, intravenous antibiotics and hospitalization may be needed for more serious infections.
The provider may prescribe antibiotics such as cephalexin or clindamycin for 5 to 14 days. A dermatologist or infectious disease specialist may be involved in severe or complicated cases.
Acetaminophen may also be recommended to reduce fever and relieve pain or discomfort during treatment.
It is important to monitor the affected area and keep any associated wounds clean and properly covered. Follow your healthcare provider's wound care instructions to support healing.
Cellulitis antibiotics
The antibiotic used to treat cellulitis depends on the severity of the infection, the bacteria that are most likely causing it, the person's allergies, and whether there is a risk of MRSA. Cephalexin is commonly prescribed for uncomplicated cellulitis, while clindamycin may be used in certain cases.
If MRSA coverage is needed, the provider may prescribe sulfamethoxazole/trimethoprim together with cephalexin. More serious infections may require intravenous antibiotics, such as cefazolin or vancomycin.
How long does cellulitis last?
Cellulitis symptoms usually begin to improve about 48 hours after antibiotic treatment is started. However, complete recovery varies from person to person and may take 5 to 14 days, depending on the treatment period recommended by a healthcare provider.
If symptoms become worse during treatment, the antibiotic may need to be changed. Hospitalization may also be necessary so that medication can be given through a vein and the infection can be prevented from spreading throughout the body.