Cellulitis develops when bacteria enter through a break in your skin and infect the deeper layers of tissue beneath the surface. The break doesn’t have to be obvious. Something as small as a crack between your toes from athlete’s foot, a minor scrape, or even dry, cracked skin can be enough to let bacteria in. Skin and soft tissue infections affect roughly 77 out of every 1,000 people per year in the United States, and cellulitis is one of the most common types.
How Bacteria Get In
Two types of bacteria cause most cases of cellulitis: staph and strep. Both live on your skin normally without causing problems. They only become dangerous when they slip past the skin’s outer barrier and reach the tissue underneath.
The entry points that allow this are sometimes called “portals of entry,” and they include:
- Cuts, scrapes, and surgical wounds
- Insect bites or animal bites
- Puncture wounds
- Cracked, dry skin, especially on the feet or hands
- Skin conditions like athlete’s foot or eczema that create tiny breaks in the skin
- Pressure sores or ulcers
Injuries that happen in lakes, rivers, oceans, or hot tubs carry extra risk because the water itself may contain bacteria that cause infection. Surgical incisions are another common entry point, particularly in the legs. After vein-harvesting surgery for heart bypass, for example, roughly 4 to 6 percent of patients develop cellulitis at the donor site.
Why Some People Are More Vulnerable
Not everyone who gets a cut develops cellulitis. Several conditions tip the odds significantly.
Swelling from fluid buildup (edema or lymphedema) is one of the strongest risk factors. When the lymphatic system is damaged or sluggish, it can’t clear bacteria and their byproducts efficiently. The immune response in that limb becomes locally impaired. Research on women with arm lymphedema after breast cancer treatment found that their skin’s ability to mount an immune reaction was measurably reduced in the affected limb.
Diabetes raises your risk because high blood sugar slows wound healing and weakens immune function. Poor circulation in the legs, common in both diabetes and venous insufficiency, compounds the problem by reducing the flow of infection-fighting cells to the area. Obesity is another factor, partly because it increases the likelihood of skin folds that trap moisture and partly because it contributes to swelling in the lower legs.
Why Cellulitis Keeps Coming Back
One of the most frustrating aspects of cellulitis is that having it once makes you more likely to get it again. This isn’t bad luck. It’s biology.
Each episode of cellulitis damages the lymphatic vessels in the affected area. Damaged lymphatics drain fluid less effectively, which creates more swelling, which further weakens the local immune response. This creates a self-reinforcing cycle: infection damages the lymphatic system, the weakened lymphatic system invites more infection. Researchers describe this as an “immunocompromised district,” a localized zone where the body simply can’t fight bacteria as well as it does elsewhere. Some patients experience dozens of recurrences. One case report documented 20 separate episodes of cellulitis at the same surgical site.
Athlete’s foot plays a surprisingly central role in recurrent leg cellulitis. The fungal infection creates persistent cracks in the skin between the toes, giving bacteria a reliable entry point. In patients with lymphatic damage, clearing the athlete’s foot can break the cycle of recurring cellulitis entirely.
What Cellulitis Looks and Feels Like
Cellulitis typically starts as a red, swollen, warm area of skin that feels tender or painful to the touch. The redness spreads outward over hours or days, and the borders are usually not sharply defined. The skin may look tight or glossy from the swelling. Some people describe it as looking like a sunburn at first, but it feels distinctly different because of the warmth and pain beneath the surface.
As the infection progresses, you may develop fever, chills, and fatigue. Red streaking from the infected area toward nearby lymph nodes is a sign the infection is moving through the lymphatic system. A rash that’s changing or spreading rapidly, especially with fever, is a reason to seek emergency care. Without fever but with a growing rash, getting seen within 24 hours is important.
When Cellulitis Becomes Dangerous
Most cellulitis responds well to antibiotics when caught early. But untreated or undertreated, it can escalate. The bacteria can enter the bloodstream and cause sepsis, infect heart valves, or spread to bone. In rare cases, infection reaches the deep tissue layers and causes necrotizing fasciitis, a rapidly destructive condition that requires emergency surgery.
Complications from skin and soft tissue infections have been increasing. Between 2011 and 2019, the rate of complicated cases nearly doubled in the U.S., rising from about 3.5 to 6.3 per 1,000 people per year. Hospitalizations for these infections hold steady at around 2 per 1,000 people annually, and the mortality rate among hospitalized patients sits between 0.9 and 1.1 percent. These aren’t large numbers on an individual level, but they underscore why early treatment matters.
Reducing Your Risk
Prevention comes down to protecting your skin barrier and treating problems before bacteria have a chance to settle in.
Keep skin clean and well moisturized, especially on the lower legs, feet, and hands. Dry, cracked skin is an open invitation. Wear gloves for gardening or any work that risks cuts. Use appropriate footwear to protect your feet. Trim your nails carefully to avoid nicking the surrounding skin.
Treat athlete’s foot promptly and completely. This is one of the most overlooked prevention steps, particularly for people who’ve already had cellulitis in their legs. Any cut, scrape, or bite should be washed with soap and water and kept clean while it heals. If you notice signs of infection (increasing redness, warmth, swelling), don’t wait to see if it resolves on its own.
For people with multiple recurrences, long-term low-dose antibiotic therapy is sometimes used as a preventive measure. Managing underlying conditions like lymphedema through compression therapy and decongestive physiotherapy also helps. Research shows that reducing limb swelling can partially restore the local immune function that lymphatic damage takes away.