Cellulitis may have different symptoms depending on the type of bacteria involved and where on your body it affects. These factors may influence which antibiotics a doctor prescribes to treat cellulitis.

Cellulitis is an infection of the deep layers of your skin. You can get cellulitis on any part of your body, but most people get it in their leg or foot.

There are different ways doctors may classify cellulitis, which can determine which treatments may be most effective.

Keep reading to learn about the different types of cellulitis, the symptoms they cause, and when to contact a doctor for diagnosis and treatment.

Cellulitis is the result of bacteria. The type of bacteria at fault may influence your course of treatment.

Although most cases of cellulitis develop from different strains of Staphylococcus, you can get cellulitis from many kinds of bacteria.

  • Staphylococcus: Staphylococcus aureus is a major cause of cellulitis. Staphylococcus (staph) infections are sometimes called “purulent cellulitis,” as pus, fluid, or abscesses are often among the symptoms.
  • Streptococcus: Streptococcus pyogenes is one of the most common causes of cellulitis. Cellulitis from Streptococcus can happen after an incision, burn, wound, or trauma.
  • Pasteurella multocida: Cellulitis from these bacteria usually occurs within 1–2 days of an animal bite or scratch.
  • Capnocytophaga: These bacteria naturally live in the mouths of people, cats, and dogs but can cause an infection under the right circumstances. Infections in humans are common after dog bites.
  • Vibrio vulnificus: These infections can start in open wounds that come in contact with salt water or undercooked seafood and sometimes require hospitalization.
  • Aeromonas: Various species of Aeromonas are responsible for wound and soft tissue infections like cellulitis, as well as gastrointestinal illness.
  • Haemophilus influenzae: These invasive bacteria can cause cellulitis and other illnesses like meningitis and infectious arthritis.
  • Pseudomonas: These bacteria cause infections after surgery, with Pseudomonas aeruginosa most likely to cause cellulitis.

Any area of your skin can have cellulitis. Doctors may classify cellulitis based on which part of your body it affects.

Lower limb (leg) cellulitis

Cellulitis most frequently affects the legs, and usually just one leg. Group A Streptococcus bacteria usually cause lower limb cellulitis, but staph infections may also be at fault.

Risk factors for developing lower limb cellulitis include:

Perianal cellulitis

Perianal cellulitis develops in your anal area and is typically due to streptococcal infection. Also known as perianal streptococcal dermatitis, this type primarily affects children under the age of 10 years. It’s also two to three times more common in male children.

Doctors usually treat perianal cellulitis with a combination of oral and topical medications.

Orbital cellulitis

Orbital cellulitis affects the fat and muscles around your eyes. It usually develops from a bacterial sinus infection that spreads to the area just behind your eyes. It’s most common in children.

Antibiotics for 2–3 weeks are usually enough to treat orbital cellulitis, but severe cases may require surgery.

Periorbital cellulitis

Also known as preseptal cellulitis, periorbital cellulitis affects your eyelid or the skin around your eye. Like orbital cellulitis, it may be due to a sinus infection, but it can also be due to a wound. Staph and strep infections are often at fault, mostly affecting children.

Periorbital cellulitis is less serious and more common than orbital cellulitis. However, it may progress to orbital cellulitis without treatment. It usually resolves after 5–7 days of antibiotics.

Facial cellulitis

Haemophilus influenzae was a common cause of cellulitis affecting the face, most often in children under age 5 years. However, increased vaccination rates have made this condition less common.

But other bacteria can also cause facial cellulitis, including bacteria in your mouth that contribute to cavities. In such cases, a dentist may need to extract the affected tooth.

Breast cellulitis

Although it can develop from a wound, breast cellulitis typically occurs after breast cancer surgery, breast augmentation, or breast reduction.

According to a 2018 research review, 3–8% of people develop cellulitis after breast cancer surgery. But that number may be higher as some cases go unreported. While cellulitis often develops within weeks after a wound, breast cellulitis can develop months after surgery.

What are the most common locations of cellulitis on the body?

Adults usually get cellulitis on one leg or foot. Children tend to get the infection on their neck or face.

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Doctors may also classify cellulitis as purulent or nonpurulent.

Purulent cellulitis means that symptoms include pus, an abscess, or phlegmon. A phlegmon is similar to an abscess but can spread beyond the main area of infection. Purulent cellulitis is usually due to Staphylococcus aureus infections like MRSA.

Nonpurulent cellulitis is usually due to group A, B, C, or G Streptococcus infections.

Erysipelas is a superficial skin infection that doesn’t extend into the deeper layers of skin. It’s typically in a clearly defined area of skin.

Cellulitis causes stronger skin discoloration than erysipelas.

You might experience swelling and pain for either condition. But if you feel generally unwell, it’s more likely you have erysipelas.

Staphylococcus or Streptococcus bacteria are common causes of both, but cellulitis is most commonly from Staphylococcus, while erysipelas is usually from Streptococcus.

Antibiotics are the typical treatment for cellulitis. A doctor will choose an antibiotic that treats the specific bacteria causing the infection.

A typical antibiotic course for cellulitis is at least 5 days. If cellulitis doesn’t get better, a doctor might recommend extending the course.

Oral antibiotics are the standard treatment for mild cellulitis. A doctor might consider intravenous (IV) antibiotic therapy if you have a more severe infection.

A doctor might recommend keeping the affected area elevated to prevent a new infection. In cases of purulent cellulitis, they may also try to remove the abscess or phlegmon.

Contact a doctor if you have symptoms of cellulitis such as:

  • swelling
  • warm and tender skin
  • painful area of skin
  • color changes

Seek medical attention immediately if:

  • skin discoloration spreads quickly
  • you have a fever or chills
  • you have an infection around your eye

Cellulitis is a bacterial infection that goes into the deeper layers of your skin. What type of bacteria causes the infection, where the infection occurs, and the presence of certain symptoms may influence what treatments a doctor prescribes.

Several days of antibiotic therapy is the standard treatment for mild cellulitis. If you have a severe case, a doctor might recommend IV antibiotic therapy.