Let’s Talk About Cellulitis
We’ve got the doctor-approved scoop on cellulitis causes, symptoms, treatments, and a ton of other facts and tips that can make life with this challenging skin infection easier.
At first you thought you were imagining that red circle on your lower leg. It didn’t bother you much at the time, but now that it feels hot when you touch it and is starting to swell and maybe even expand, you’re pretty sure there’s something going on there. Your doctor is concerned that it’s a bacterial skin infection called cellulitis and wants you to come in ASAP. Cell-u-what? Here’s what you need to know.
Our Pro Panel
We went to some of the nation’s top cellulitis experts to bring you the most scientific and up-to-date information possible.
Gina A. Suh, M.D.
Infectious Diseases Specialist
Jun Kevin Kang, M.D.
Assistant Professor of Dermatology
Johns Hopkins Medicine
Ohara Aivaz, M.D.
Los Angeles, CA
Cellulitis typically appears on a lower leg or foot as a “sheet” of redness. It may feel warm to the touch and may appear in circular form. Cellulitis may also swell and become painful.
There is no test for cellulitis. Instead, your doctor will make the diagnosis by looking at the affected area and ruling out other conditions that may look like cellulitis. Sometimes blood work or a culture of any fluid or pus around the infection site may also be needed.
The bacteria can enter the deeper layers of your skin and potentially your bloodstream, causing infection in other areas of your body. While rare, cellulitis can also lead to infection with the flesh-eating disease necrotizing fasciitis. This is why you want to catch and treat cellulitis early.
Controlling risk factors is the best way to stave off infection. If you have diabetes, check your feet regularly for cuts and make sure your blood sugar is well-controlled. Clean cuts thoroughly and put a bandage over it until it heals. Talk to your doctor about your risks and how best to manage them.
What Is Cellulitis, Anyway?
Cellulitis is a serious skin infection that occurs when bacteria infect the deep layers of your skin and the tissue beneath it. It is most commonly caused by either Streptococcus pyogenes (strep) or Staphylococcus aureus (staph) bacteria. However, it can also stem from the more serious MRSA (methicillin-resistant Staphylococcus aureus), a type of staph infection that’s become more resistant to antibiotics.
Often, there is some type of cut or break in your skin that allows bacteria to enter, but sometimes there is no such event—or at least none that you can recall. Your skin may be cut or punctured in any number of ways, from a shaving nick to a tattoo or body piercing, or from injection drug use or an animal bite.
Though most people have never heard of cellulitis, it’s not a rare condition. In fact, there are more than 14 million cases of cellulitis in the United States each year. Both men and women can get cellulitis, and it equally affects both genders. And when it comes to age, while you can get cellulitis at any point in your life, it more commonly occurs in those who are middle-aged and older.
An important tidbit: Cellulitis is not commonly passed on to people around you and it's not contagious like a common cold, but you can spread the bacteria to other people (known as a community-acquired infection). Let’s take a closer look at what’s behind this painful condition.
What Are the Symptoms of Cellulitis?
Cellulitis can show up on any part of the body, but often it develops on a foot or lower leg, places where certain conditions that may make you more susceptible to cellulitis can strike (more on what those are later). It is almost always unilateral, meaning it occurs on just one side of your body. In kids, cellulitis often appears on the face, as this is where they’re more likely to get scratches. The infection tends to occur close to where an initial skin injury took place, if there was one. These are some other common signs of cellulitis:
Cellulitis appears as one area or “sheet” of redness. It may start off at about the size of a quarter on your calf, for instance, and quickly grow to cover your entire lower leg. It is not raised, and there aren’t any spots or dots. It may be circular, but it could also take on other shapes as well.
Your skin may feel warm when you touch the affected area. This heat is generated by your body’s immune system, which is trying to fend off the infection. You may also experience tenderness or pain when you touch the affected area.
Your skin may appear pitted (which can look similar to the uneven, dimpled skin of an orange), and you may develop blisters in the area, too. In cases of severe infection, you will also see pus.
Cellulitis can come on suddenly or more gradually, surfacing over several days or weeks and tending to grow redder, more swollen, and more painful with time. It may start off slowly, but once it is there, it may expand quickly. If the red area rapidly expands, your infection may be spreading to other parts of your body. Symptoms that raise the possibility that cellulitis is on the move include:
Swollen glands or lymph nodes
What Are the Risk Factors for Cellulitis?
Pretty much anyone can develop cellulitis and, once you’ve had it, you’re at higher risk for getting it again. This is often because of certain underlying and untreated—or undertreated—conditions you may have that can make you more susceptible to cellulitis. For instance, chronic skin conditions like athlete’s foot and eczema may help set the stage for cellulitis. Athlete’s foot can cause microscopic tears in the skin that serve as portals of entry for hungry bacteria. With eczema, your skin barrier may be compromised, especially if you scratch, enabling bacteria to enter and cause cellulitis. Chickenpox and/or shingles can increase your chances of developing cellulitis for similar reasons.
Other medical conditions make you more prone to cellulitis:
You Have Diabetes
Diabetes ups your risk of infection for a variety of reasons. For instance, you may develop ulcers on your feet if you can’t feel minor problems, like a cut, early on because of nerve damage. People with uncontrolled diabetes often have high blood sugar, and there is nothing that bacteria like to eat more than sugar. Put together elevated blood sugar and an open wound that goes unnoticed, and you have the perfect storm for cellulitis.
You Have Lymphedema
If your feet, legs, hands, and/or arms are swollen due to lymphedema, you are more prone to developing cellulitis. Lymphedema happens when lymph fluid builds up in the soft tissues of your body. It usually occurs in your arms or legs and can result from radiation therapy, the surgical removal of lymph nodes such as from cancer surgery, and some genetic conditions. Your lymph system is supposed to fight off infection, but when it’s overloaded, it can’t do its job and infections like cellulitis may occur.
Your Immune System Is Compromised
This can occur for many reasons, including taking steroid medications, chemotherapy to treat cancer, other medicines that suppress the immune system, and/or certain underlying diseases and conditions. Your risk for infection soars when your immune system isn’t working well. A compromised immune system just can’t do its job as it should, a job that includes fighting off intruders, such as the bacteria that can cause cellulitis, that make their way into the body.
Poor circulation in your arms, legs, hands, or feet due to excess weight can cause swelling, which sets the stage for cellulitis. When your skin stretches out, it becomes more prone to cracks and tears, which serve as portals for bacteria to enter.
You Had Heart Surgery
Heart surgery that involves having a vein removed from your leg and reconnecting it to your coronary artery to boost blood flow to your heart may increase your risk of cellulitis if the surgery results in leg swelling.
How Is Cellulitis Diagnosed?
Your doctor can likely take one look at the red area on your lower leg and tell you whether or not you have cellulitis. You may be asked to circle the area with a marker now, to see if it gets any larger in the future. (Doing this on your own is not a replacement for seeking a medical evaluation.)
There is no official cellulitis test, so your doctor will ask lots of questions and try to eliminate other diseases that may look like cellulitis. This list of cellulitis imitators includes:
Chronic venous insufficiency (CVI). This vein diseases in your lower leg can mimic the appearance of cellulitis.
Contact dermatitis. Skin irritation from allergic or contact dermatitis can result in red patches similar to cellulitis.
You may need other tests, such as a complete blood count, or CBC, to see if your infection has started to spread. One part of this blood test, which involves taking a small amount of blood from a vein in one of your arms, looks at your white blood cell count. Your immune system uses white blood cells to fend off bacteria, viruses, and other foreign invaders when you’re sick. So, when you’re sick, your body needs to generate more white blood cells to fight these invaders off. A higher count of white blood cells in your CBC may indicate that your immune system is working overtime to fend off an infection.
If there is pus at the site of the infection, your doctor may take a culture and send it to a lab. Knowing what type of bacteria you are dealing with can help guide your treatment.
As cellulitis worsens, the bacteria enter deeper layers of your skin and potentially your bloodstream. Without treatment, the infection can spread to other areas of your body, namely your blood, joints, bones, and/or the lining of the chambers of your heart and heart valves, a condition called endocarditis.
Although rare, cellulitis may also lead to a very serious infection called necrotizing fasciitis, or flesh-eating bacteria. This is an extreme emergency. Strep bacteria are among the most common causes of cellulitis, and necrotizing fasciitis can happen when the infection is from a very aggressive strep strain called group A streptococcus (GAS). See your doctor ASAP if you experience severe pain and swelling of the affected skin area, or blistering.
Treatment for Cellulitis
If your doctor confirms that you have cellulitis, you will likely be started on oral antibiotics right away, probably a broad-spectrum antibiotic that targets the most common cellulitis culprits. More serious infections—such as those more widespread, those with additional symptoms like high fever and a general feeling of malaise, and those that oral antibiotics have failed to help—may need to be treated in the hospital with intravenous (IV) antibiotics. In these cases, information on what type of bacteria is causing the infection may help your doctor choose the best drug. When the infection is in an arm or leg, keeping the affected limb elevated can help decrease swelling and speed recovery.
When you catch cellulitis early, you will likely recover quickly and fully. You should see improvements in 24 to 48 hours of starting treatment. This means less pain and swelling, and the red area should start to shrink, too.
If you have had multiple bouts of cellulitis as well as risk factors such as lymphedema or diabetes, your doctor may consider putting you on a preventive course of antibiotics to keep repeat infections at bay. The risk and benefits of this practice must be weighed carefully, since overuse of antibiotics can lead to the development of superbugs—bacteria that don’t respond to treatment.
How to Prevent Cellulitis
Unfortunately, cellulitis is not a one-and-done illness. Once you’ve had cellulitis, you have a greater chance of getting it again, especially if you have underlying conditions that predispose you to it. The good news: Following these guidelines can help you minimize your risk of a future infection.
Start by taking good care of any and all skin wounds (even minor shaving nicks) when they happen. Clean all minor cuts and injuries that break the skin with soap and warm water, apply an antibiotic ointment, and cover with bandages until they heal. If your wound is deep, such as a dog bite, see your doctor.
When you have a wound, stay away from hot tubs, pools, and natural bodies of water like lakes and rivers, all of which can harbor bacteria that could infiltrate your broken skin barrier and cause another bout of cellulitis.
Prevention also means taking care of any and all underlying conditions that predispose you to cellulitis. If you have diabetes, check your feet daily for injuries or signs of infection, and make sure you see a podiatrist regularly. It’s also important to keep your blood sugar in the normal range. Work closely with your doctor to make sure you’re doing all that you can to keep your diabetes under tight control.
If you have had multiple cellulitis infections below the knee, see a doctor to find out if you have athlete’s foot. If you do, treat it to lower the chances that you will develop cellulitis again. This entails topical creams to get the infection under control, along with taking measures to prevent a repeat, including keeping your feet clean and dry and your toenails short and clean so bacteria stay out.
In general, it’s important to moisturize daily to keep your skin barrier intact so that it can do its job and keep bacteria out. If you tend to experience limb swelling, ask your doctor about wearing compression stockings or a leg wrapping to reduce swelling and stave off cellulitis.
Along with these basic DIY prevent methods, these lifestyle changes can also help reduce your risk for repeat bouts of cellulitis:
Limiting alcohol use, since drinking too much dampens your immune system
Maintaining a normal weight
It’s scary to hear that you have cellulitis, but catching it early gives you a true head start on averting some of the potential consequences. Take your antibiotics as directed, and you should start feeling better ASAP. Now that you have had it once, you are at risk for getting it again, so make sure to clean all wounds carefully and stay on top of all underlying conditions that predispose you to cellulitis.
Cellulitis Statistics: StatPearls. (2020.) “Cellulitis.” https://www.ncbi.nlm.nih.gov/books/NBK549770/
Cellulitis Overview: U.S. National Library of Medicine. (2019.) “Cellulitis.” https://www.medlineplus.gov/ency/article/000855.htm
Cellulitis Overview: Centers for Disease Control and Prevention. (2020.) “Cellulitis.” https://www.cdc.gov/groupastrep/diseases-public/Cellulitis.html
Cellulitis Onset: UpToDate. (2019.) “Patient education: Skin and soft tissue infection (cellulitis) (Beyond the Basics).” https://www.uptodate.com/contents/skin-and-soft-tissue-infection-cellulitis-beyond-the-basics
Lymphedema: U.S. National Library of Medicine. (2020.) “Lymphedema.” https://www.medlineplus.gov/lymphedema.html
White Blood Cell Count: U.S. National Library of Medicine. (2020.) “White Blood Count (WBC).” https://www.medlineplus.gov/lab-tests/white-blood-count-wbc/