Cellulitis: Warning Signs of a Spreading Skin Infection and When to Be Seen

What it involves

MedlinePlus describes cellulitis as a common bacterial infection of the middle layer of the skin and the tissue underneath, and occasionally the muscle below. Staphylococcus and streptococcus bacteria are the usual causes, and they get in through a break in the skin.

Who this is for

• Patients with a red, warm, tender patch of skin that has gotten bigger since it first appeared
• Patients with diabetes who notice a sore or crack on a foot that looks inflamed
• Patients who had a cut, bite, or surgical wound that now looks worse instead of better
• Patients who had cellulitis before and want to know what keeps it from returning

What to expect

• Questions about when the redness started, how fast it has spread, and any fever or chills
• A close look at the skin, with the edge of the redness possibly marked with a pen
• A review of your health conditions and medicines, especially diabetes and anything that lowers immunity
• A plan that may include antibiotics, follow-up to see whether the redness is shrinking, or a referral for hospital care

How it gets started

Healthy skin carries many bacteria and normally keeps them out. MedlinePlus says a crack, scrape, insect or animal bite, surgical wound, or skin ulcer gives them a way in. Peeling or cracked skin between the toes is a common entry point, and the athlete's foot guide covers that problem. A bite that turns angry-looking is also worth reading about in the insect bites and stings guide.

What it looks and feels like

MedlinePlus lists the typical picture. A sore or rash begins suddenly and grows quickly during the first day:

• Redness that gets larger as the infection spreads
• Skin that feels warm, tender, and sore to touch
• A tight, shiny, stretched look to the skin
• Fever, chills, sweating, tiredness, or muscle aches
• Nausea or vomiting in more serious cases

Who is more likely to get it

MedlinePlus names poor circulation in the legs, diabetes, vascular disease, and medicines that suppress the immune system as risk factors. It also says fungal infections of the feet can lead to cellulitis that keeps coming back, particularly in people with diabetes, because the cracks let bacteria in. Good blood sugar control is part of prevention, which the diabetes management page explains.

Why a visit matters

MedlinePlus says untreated cellulitis can spread to the blood, bone, heart lining, or the covering of the brain, so it is not a rash to watch for a week. A provider examines the area, may mark the border of the redness to see whether it moves past the line over the next days, and may order a blood count or cultures. A complete blood count is one of the tests MedlinePlus lists.

Treatment and home care

MedlinePlus says treatment is usually antibiotic pills, sometimes with pain medicine, and symptoms generally clear after 7 to 10 days of antibiotics, longer when the infection is severe or immunity is weak. At home it recommends raising the affected limb above heart level to reduce swelling and resting until the symptoms ease. Hospital care is suggested for people who are very sick, whose redness keeps spreading on antibiotics, or who have an infection near the eyes.

Call the same day if

MedlinePlus says to contact a provider right away with signs of cellulitis, and again if treatment has started but you develop a persistent fever, drowsiness, blistering over the area, or red streaks that spread. A fever on its own is covered in the fever in adults guide. Shaking chills with confusion or fast breathing need emergency care.

Keeping it from coming back

MedlinePlus suggests keeping skin moisturized so it does not crack, wearing shoes with room for the feet, and trimming nails carefully. For any break in the skin it recommends washing with soap and water, applying petroleum jelly daily, covering with a bandage changed every day, and watching for redness, pain, or drainage.

Sources

• MedlinePlus — Cellulitis
• MedlinePlus — Skin Infections