Cellulitis in the leg is a bacterial skin infection that causes redness, swelling, warmth, and pain in the affected area. It happens when bacteria enter through a break in the skin and infect the deeper layers, including the tissue just beneath the surface. The lower leg is the most common site for cellulitis, and the infection almost always appears on just one leg, not both.
What Causes Leg Cellulitis
Two types of bacteria are responsible for the vast majority of cases. Non-purulent cellulitis, the kind without visible pus, is typically caused by group A Streptococcus. Purulent cellulitis, which involves abscesses or pus you can see or press out of the skin, is usually caused by Staphylococcus aureus. Less common bacteria can be involved in specific situations: animal bites can introduce different organisms, and exposing a wound to salt water or fresh water carries its own bacterial risks.
The bacteria need a way in. Any break in the skin can serve as that entry point: a cut, a scrape, a surgical wound, a cracked heel, or even skin damage from conditions like eczema or athlete’s foot. Athlete’s foot is especially relevant for leg cellulitis because the cracked, peeling skin between the toes creates an opening that bacteria exploit to cause infection higher up the leg.
Who Is Most at Risk
Several factors make leg cellulitis more likely. Chronic swelling in the legs is one of the biggest. When fluid pools in your lower limbs from conditions like lymphedema (where the lymphatic system doesn’t drain properly) or venous insufficiency, the stretched, waterlogged skin becomes more vulnerable to bacteria. People who’ve had coronary artery bypass surgery using a leg vein sometimes develop chronic swelling in that leg afterward, raising their risk.
Being overweight increases risk as well, partly because excess weight contributes to leg swelling and skin breakdown. Diabetes plays a role too, since high blood sugar impairs the body’s ability to fight infection. Chronic skin conditions like eczema and shingles weaken the skin barrier. And if you’ve had cellulitis before, your chances of getting it again are significant: recurrence rates range from 16% to 53% within three years.
What Leg Cellulitis Looks and Feels Like
The hallmark is an area of red, inflamed skin that feels warm and tender when you touch it. The redness typically spreads outward from the infection site, and the skin often looks smooth and shiny rather than flaky or crusty. You may notice swelling that makes the skin look tight, and in some cases the swollen skin develops a dimpled texture resembling an orange peel. Pain is a defining feature: the area hurts, not just itches.
Beyond the local skin changes, cellulitis can make you feel sick. Fever, chills, and general fatigue are common because your immune system is fighting an active bacterial infection. Some people develop spots on the skin or blisters over the infected area. When blisters do form, they tend to be large, unlike the small, weepy blisters typical of eczema.
Conditions That Look Similar
One of the trickiest aspects of leg cellulitis is that it can look a lot like other conditions, particularly varicose eczema (also called stasis dermatitis). Both cause red, inflamed skin on the lower legs. But the differences are clear once you know what to look for.
Varicose eczema itches rather than hurts, doesn’t cause fever, and produces crusting or scaling on the skin surface. It also tends to appear on both legs and sometimes other parts of the body. Cellulitis, by contrast, is painful, may cause fever, affects one leg, and produces smooth, shiny skin without crusting. If someone has a history of varicose veins or prior blood clots, redness in the leg is more likely eczema. A deep vein thrombosis (blood clot) can also cause a red, swollen leg and sometimes needs to be ruled out with an ultrasound.
How It’s Treated
Antibiotics are the standard treatment. For uncomplicated cellulitis, a 5 to 7 day course of oral antibiotics is the current recommendation. Purulent cases involving abscesses may need drainage along with a 7-day antibiotic course. People with more extensive infections who need hospital treatment sometimes require up to 10 days.
The type of antibiotic depends on whether the infection involves pus or not, since the likely bacteria differ between the two types. Your doctor will choose the appropriate class based on what the infection looks like.
While on antibiotics, elevating your leg helps reduce swelling and supports healing. The goal is to rest with your affected leg raised above the height of your chest when possible. This uses gravity to move fluid out of the swollen tissue. Keeping the leg down, especially standing or sitting for long periods, works against recovery.
What to Expect During Recovery
Cellulitis doesn’t always look better right away after starting antibiotics. In fact, redness can continue to spread slightly during the first day or two of treatment as the immune response catches up. Doctors often outline the border of the redness with a pen so you can track whether it’s expanding or shrinking over time.
You should see meaningful improvement within 48 to 72 hours. If the redness keeps spreading past that point, the pain is getting worse rather than better, you develop large blisters, or you can’t shake a fever, those are signs the infection may not be responding to the chosen antibiotic or something more serious is developing.
Warning Signs of Serious Complications
Most cellulitis resolves with antibiotics, but complications can occur. An abscess may form within the infected area, requiring drainage. Rarely, bacteria can enter the bloodstream, leading to sepsis. Signs that suggest this is happening include a fever above 100.4°F combined with a rapid heart rate, fast breathing, or feeling significantly worse overall.
The most dangerous complication is necrotizing fasciitis, a rapidly progressing infection that destroys the tissue beneath the skin. This is rare but requires emergency surgery. The key warning signs are pain that seems far worse than the visible infection would explain, a crackling sensation under the skin when pressed, and rapidly worsening symptoms despite antibiotics. This is a true emergency.
Preventing Recurrence
Because cellulitis comes back so frequently, prevention matters. The first step is managing whatever made you vulnerable in the first place. If athlete’s foot created the entry point, treating and preventing it closes that door. If chronic leg swelling is the issue, compression stockings can make a substantial difference. One study found that compression therapy reduced the risk of recurrence by 77% compared to education alone.
Pneumatic compression devices, which inflate and deflate around the leg to push fluid upward, also reduce recurrence in people with chronic swelling from venous insufficiency or lymphedema. For people with diabetes, maintaining good blood sugar control lowers the risk of future episodes.
For people who get cellulitis repeatedly despite managing their risk factors, preventive antibiotics are an option. A review of five clinical trials found that prophylactic antibiotics reduced recurrence by 69%. On average, treating six people with preventive antibiotics prevented one recurrence. The benefit lasts only while taking the medication, so the decision involves weighing ongoing antibiotic use against the frequency and severity of infections.