That warm, red, swollen area on your skin? It could be cellulitis

Hot summer weather and bug bites can raise your risk for this common skin infection. Early treatment is key to prevent it from worsening and spreading.
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Cellulitis is an infection in the skin caused by bacteria in which the skin becomes red and swollen. It can appear anywhere on the body, but it usually shows up on the legs in adults and on the face or neck in children.AleksandarNakic / Getty Images stock

What is cellulitis? Cellulitis is an infection in the skin caused by bacteria in which the skin becomes red and swollen. It can appear anywhere on the body, but it usually shows up on the legs in adults and on the face or neck in children, according to the American Academy of Dermatology (AAD). If it infects the skin around the eyes it’s called periorbital cellulitis.

“Cellulitis sometimes can happen following a cut or wound, and it can happen after surgery as well, around an incision,” said Dr. Allison Arthur, a dermatologist and dermopathologist at Sand Lake Dermatology Center in Orlando, Florida, and a member of the American Academy of Dermatology.

It’s a common infection on the skin — the AAD estimates that 14.5 million people in the U.S. get cellulitis every year.

Cellulitis in the legs usually shows up on just one leg. “If you think you have it in both legs, chances are something else is going on,” said Dr. Laura Ferris, associate professor and director of clinical trials in the dermatology department at the University of Pittsburgh Medical Center and a member of the American Academy of Dermatology.

It’s often confused with stasis dermatitis, where the legs get red, itchy and swollen because the fluid doesn’t get pumped out of them properly. “For stasis dermatitis, you don’t need antibiotics; you need compression to get the fluid out of the legs,” Ferris said.

Symptoms of cellulitis

With cellulitis, you’ll find that an area of skin is red, swollen and warm. You might notice that it’s painful if you press on it. With a severe infection, you might see blisters, swollen lymph nodes, a red streak, an open sore or a bump that contains pus.

You could also have other signs of infection, such as fever, chills, fatigue, cold sweats, nausea, sleepiness or difficulty concentrating, according to the AAD.

Causes of cellulitis

What causes cellulitis? Two common types of bacteria are often causes of cellulitis — streptococcus (aka strep) and staphylococcus (aka staph). These bacteria live on our skin, but can be harmful if they find an opening in the skin and get into the body.

According to the AAD, entry points for bacteria could be:

  • Sores
  • Burns
  • Cuts, scratches or abrasions
  • Cracks from eczema, athlete’s foot or dry skin

You’re at higher risk for cellulitis if you:

  • Are middle-aged or older
  • Are overweight or obese
  • Have diabetes or long-term liver or kidney disease
  • Recently had surgery
  • Injure your skin frequently, for example, if you’re an athlete or an active-duty member of the military

Summertime also presents some factors that can increase your chance of cellulitis infection, such as hot temperatures and insects. Cellulitis, said Ferris, can occur more frequently in summer because of "leg swelling, risk of injuring (your) feet walking barefoot and, possibly, from bug bites too."

“Cellulitis sometimes can happen following a cut or wound, and it can happen after surgery as well, around an incision,” said Dr. Allison Arthur.Wendy Townrow / Getty Images stock

Diagnosing cellulitis

Your doctor can diagnose cellulitis by examining your skin and asking questions about your health history, medical conditions, medications and recent injuries, according to the AAD.

Arthur points out that a lot of times, dermatologists’ schedules are booked out in advance for specialty appointments. So people often see their primary care physician or visit an urgent care center or an emergency room if they suspect cellulitis.

Treatment for cellulitis

Doctors prescribe antibiotics for treatment of cellulitis. They often turn to penicillin, cephalosporin or erythromycin, according to the American Osteopathic College of Dermatology (AOCD). For severe cases you might need IV antibiotics administered in a hospital.

Cellulitis in the legs usually shows up on just one leg. “If you think you have it in both legs, chances are something else is going on,” said Dr. Laura Ferris.Casa nayafana / Shutterstock

According to the AAD, to help your body heal, you’ll also need to care for the wound where the infection entered your body, get plenty of rest, and elevate your leg if that’s where you have cellulitis.

It’s important to treat cellulitis to prevent it from getting worse and to keep the infection from spreading.

You can help prevent cellulitis by keeping any wounds clean and covered with bandages, according to the AAD.