Cellulitis: Types, Causes, Symptoms, & Treatment (original) (raw)

What is cellulitis?

Cellulitis

Staphylococcus and Streptococcus are the types of bacteria that are usually responsible for cellulitis.

Cellulitis is a bacterial infection of the skin and tissues beneath the skin. Cellulitis may overlap with like impetigo and erysipelas, which are superficial skin infections. Cellulitis also involves the skin's deeper layers: the dermis and subcutaneous tissue.

Impetigo involves the superficial dermis, while erysipelas involves the superficial dermis and superficial lymphatic tissues that carry fluids through these layers of skin. These conditions may overlap with cellulitis. For example, Streptococcus may cause both superficial and deep skin infection at the same time, so that symptoms of impetigo or erysipelas may occur along with those of cellulitis.

The main bacteria responsible for cellulitis are Streptococcus and Staphylococcus ("strep"), the same bacteria that can cause impetigo and other diseases. MRSA (methicillin-resistant Staph aureus) can also cause cellulitis. Sometimes, other bacteria (for example, Hemophilus influenzae, Pneumococcus, and Clostridium species) may cause cellulitis as well. Cellulitis is common and affects people of all races and ages. Men and women appear to be equally affected. Although cellulitis can occur in people of any age, it is most common in middle-aged and elderly people. Cellulitis is not contagious.

What is the difference between cellulite and cellulitis?

Cellulite and cellulitis are two different conditions. They may sound similar, but cellulite is quite common and typically harmless, while cellulitis is a bacterial infection that requires treatment with antibiotics.

It's important to understand the differences between the symptoms and warning signs of these two conditions. This understanding will help you follow the steps that you can take to prevent further damage and improve your health.

What is cellulite?

Cellulite is quite common, and many people have it. It is a lumpy appearance of your skin, usually on your thighs, stomach, or butt. Your butt may appear to have dimples.

The lumpy appearance of cellulite is caused by fat cells that have grown between the connective tissue under your skin. This causes cellulite's lumpy appearance. Cellulite is harmless.

Where does cellulitis occur?

Cellulitis may occur anywhere on the body; the legs are a common location. The lower leg is the most common location of the cellulitis infection (particularly t over the tibia or shinbone and in the foot; see the illustration below), followed by the arm, and then the head and neck areas.In special circumstances, such as following surgery or trauma wounds, cellulitis can develop in the abdomen or chest areas. People with morbid (severe) obesity can also develop cellulitis in the abdominal skin.

Special types of cellulitis are sometimes designated by the location of the infection, such as:

What are the types of cellulitis?

Cellulitis can have different names and characteristics depending on where it develops in your body.

IMAGES Cellulitis See pictures of Bacterial Skin Conditions See Images

What causes cellulitis?

What is the cause of cellulitis? The majority of cellulitis infections are caused by infection with either strep (Streptococcus) or staph (Staphylococcus) bacteria.

The most common bacteria that cause cellulitis are beta-hemolytic streptococci (groups A, B, C, G, and F); Streptococcus pyogenes and Streptococcus agalactiae are the commonest species. A form of rather superficial cellulitis caused by strep is called erysipelas and is characterized by spreading hot, bright red circumscribed area on the skin with a sharp, raised border. Erysipelas is more common in young children. The so-called "flesh-eating bacteria" are, in fact, also a strain of strep bacteria that can sometimes rapidly destroy deeper tissues underneath the skin. Fasciitis is the term used to refer to inflammation of the deep lining tissues called fascia. The streptococcal infection known as flesh-eating bacterial infection is an example of necrotizing fasciitis. Cellulitis, when untreated, may rarely spread to the deeper tissues and cause severe or necrotizing fasciitis.

Staph (Staphylococcus aureus) is another common type of bacteria that causes cellulitis. Some cases are due to methicillin-resistant S. aureus (MRSA), a particularly severe type of staph that can be acquired both in the community and healthcare facilities. MRSA is resistant to many antibiotics, including commonly uses types like amoxicillin. It is therefore more difficult to treat.

Cellulitis can be caused by many other types of bacteria. In children under 6 years of age, H. flu (Hemophilus influenzae) bacteria can cause cellulitis, especially on the face, arms, and upper torso. Cellulitis from a dog or cat bite or scratch may be caused by the Pasteurella multocida bacteria. Aeromonas hydrophilia, Vibrio vulnificus, and other bacteria are causes of cellulitis that develop after exposure to freshwater or seawater. Pseudomonas aeruginosa is another type of bacteria that can cause cellulitis, typically after a puncture wound. Some cases of cellulitis may be caused by more than one type of bacterium.

Is cellulitis contagious?

Cellulitis is not contagious because it is a soft tissue infection of the skin's deeper layers (the dermis and subcutaneous tissue), and the skin's top layer (the epidermis) provides a cover over the infection. In this regard, cellulitis is different from impetigo, in which there is a very superficial skin infection that can be contagious.

Health News

Who is prone to cellulitis?

Most commonly, cellulitis develops in the area of a break in the skin, such as a cut, small puncture wound, or insect bite. It may also appear in the skin near ulcers or surgical wounds. In some cases when cellulitis develops without an apparent skin injury, it may be due to microscopic cracks in the skin that are inflamed or irritated. Prior cellulitis or erysipelas, such as that caused by Streptococcus, may damage the superficial lymphatic drainage system. This reduces defenses against bacteria that may enter the tissues and increases the risk of recurrent infection.

This may be the case with chronic leg swelling (edema or lymphedema) due to varicose veins or other impaired venous drainage of the leg. A preexisting skin infection, such as an athlete's foot (tinea pedis), fungal infection in moist skin creases (intertrigo), or impetigo, can be a risk factor for the development of cellulitis; tinea pedis and intertrigo between the toes (toe web intertrigo) are a common cause in those with chronic edema. Likewise, inflammatory medical conditions or diseases of the skin (dermatitis) such as eczema, psoriasis, or skin damage caused by radiation therapy can lead to cellulitis.

People who have diabetes or diseases that compromise the function of the immune system (for example, advanced or poorly controlled HIV/AIDS, or those receiving chemotherapy or drugs that suppress the immune system) are particularly prone to developing cellulitis.

Conditions or diseases that reduce the circulation of blood in the veins or that reduce the circulation of the lymphatic fluid (such as varicose veins or venous insufficiency, obesity, pregnancy, or previous surgeries) also increase the risk of developing cellulitis.

Risk factors for cellulitis include:

What are the symptoms of cellulitis?

Cellulitis has characteristic symptoms and signs, such as:

The signs of cellulitis include:

Any skin wound or ulcer that produces these symptoms or signs may be developing cellulitis.

In some cases, such as with Staphylococcus aureus, cellulitis may develop into a collection of infected fluid and dead white blood cells called an abscess. An abscess may develop even a few days into antibiotic treatment and requires drainage by needle aspiration or surgical incision. If dead tissue is found (gangrene or necrotizing fasciitis), surgical treatment is critical to healing.

Other forms of noninfectious inflammation may mimic cellulitis. People with poor circulation in the legs, for instance, often develop scaly redness on the shins and ankles; this is called "stasis dermatitis" and is often mistaken for the bacterial infection of cellulitis.

What types of healthcare professionals diagnose and treat cellulitis?

Primary care specialists, including internists and family medicine specialists, treat cellulitis. For patients who seek medical treatment at an urgent care center or emergency department, emergency medicine specialists may be the treating physicians. Sometimes infectious disease specialists or surgeons may be involved in the medical treatment of cellulitis.

How do healthcare professionals diagnose cellulitis?

First, the doctor must distinguish whether or not the inflammation is due to an infection. The history and physical exam can provide clues, as can sometimes an elevated white blood cell count if laboratory testing is done.

Cellulitis is commonly treated with antibiotics that are designed to eradicate the most likely bacteria to cause the particular form of cellulitis. In most situations, bacterial culture is not necessary. Culture may occasionally be of value if pus is present In the absence of pus, the concentration of bacteria is often low, and cultures fail to demonstrate the causative organism. Cultures of chronic wounds must be interpreted with caution because they are contaminated with bacteria that are not causing infection and may lead to incorrect antibiotic treatment. If a pus-filled abscess is present, surgical drainage is typically required; in this case, culture is most reliable for guiding correct choice of antibiotics.

What is the best treatment for cellulitis?

When it is difficult or impossible to distinguish whether or not the symptoms are due to an infection, doctors sometimes treat them with antibiotics just to be sure. If the condition does not respond, it may need to be addressed by different methods dealing with types of inflammation that are not infected. For example, if the inflammation is thought to be due to an autoimmune disorder, cellulitis treatment may be with a corticosteroid.

What is the best antibiotic to treat cellulitis?

Antibiotics, such as derivatives of penicillin or other types of antibiotics that are effective against the responsible bacteria, are used to treat cellulitis. If the bacteria become resistant to the chosen antibiotics, or in patients who are allergic to penicillin, other appropriate antibiotics can be substituted. Sometimes the treatment requires the administration of intravenous antibiotics in a hospital setting, since oral antibiotics may not always provide sufficient penetration of the inflamed tissues to be effective. In some instances, intravenous antibiotics can be administered at home or an infusion center.

The following are some examples of antibiotics that have been used to treat cellulitis:

In all cases, physicians choose a treatment based on many factors, including the location and extent of the infection, the type of bacteria causing the infection, and the overall health status of the patient.

Subscribe to MedicineNet's Skin Care & Conditions Newsletter

By clicking "Submit," I agree to the MedicineNet Terms and Conditions and Privacy Policy. I also agree to receive emails from MedicineNet and I understand that I may opt out of MedicineNet subscriptions at any time.

How can you treat your cellulitis at home?

You can relieve your cellulitis symptoms with some self-care practices at home alongside your medication. These can include:

The best way to prevent cellulitis is through good hygiene and wound care practices. These include:

Does cellulitis stay in your system forever?

Cellulitis may continue to spread and not resolve until antibiotic treatment is used. Typically, the symptoms disappear three 3 to 10 days after you have begun taking antibiotics.

What are the complications of cellulitis?

Cellulitis is a treatable condition, but antibiotic treatment is necessary to eradicate the infection and avoid complications and the spread of the infection. Most cellulitis can be effectively treated with oral antibiotics at home. Sometimes hospitalization and intravenous antibiotics are required if oral antibiotics are not effective.

Sepsis is a serious complication of cellulitis. If not properly treated, cellulitis can occasionally spread to the bloodstream and cause a serious bacterial infection of the bloodstream that spreads throughout the body (sepsis or “blood poisoning”).

Other complications of cellulitis include:

These problems can lead to:

Mild cellulitis resolves quickly with antibiotic treatment, but it is important to speak to your doctor to monitor your condition.

Is it possible to prevent cellulitis?

Under some circumstances, cellulitis can be prevented by proper hygiene, treating chronic swelling of tissues (edema), and caring for wounds or cuts. In other cases, microscopic breaks in the skin may not be apparent and infection may develop.

In general, cellulitis in a healthy person with an intact immune system is preventable by avoiding skin surface wounds. In people with predisposing conditions (see above) and/or weakened immune systems, cellulitis may not always be preventable.

Frequently asked questions

Medically Reviewed on 1/6/2025

References

Boettler MA, Kaffenberger BH, Chung CG. Cellulitis: A Review of Current Practice Guidelines and Differentiation from Pseudocellulitis. Am J Clin Dermatol. 2022;23(2):153-165. doi:10.1007/s40257-021-00659-8

Rrapi, R., Chand, S., & Kroshinsky, D. (2021). Cellulitis: A Review of Pathogenesis, Diagnosis, and Management. The Medical clinics of North America, 105(4), 723–735. https://doi.org/10.1016/j.mcna.2021.04.009

Herchline, Thomas E. "Cellulitis." Medscape. June 14, 2019.

Spelman, Denis, and Larry M. Baddour. "Cellulitis and skin abscess: Clinical manifestations and diagnosis." March 28, 2019.

Raff, A. B., & Kroshinsky, D. (2016). Cellulitis: A Review. JAMA, 316(3), 325–337. https://doi.org/10.1001/jama.2016.8825

Stevens, D. L., et al. Infectious Diseases Society of America (2014). Practice guidelines for the diagnosis and management of skin and soft tissue infections: 2014 update by the Infectious Diseases Society of America. Clinical Infectious Diseases, 59(2), e10–e52. https://doi.org/10.1093/cid/ciu444