Overview
Cellulitis happens when bacteria get in through a break in the skin, like a cut, scrape, bite, burn, or cracked skin from athlete's foot. The infected area becomes red, warm, swollen, and tender.
Most cases get better quickly with antibiotics. Without treatment, the infection can spread to the blood and become life-threatening.
Symptoms
Symptoms can start suddenly and grow fast in the first day.
- Red, warm, swollen skin
- Pain or tenderness
- Skin that looks tight, shiny, or like an orange peel
- Redness that gets bigger
Less common
- Fever and chills
- Blisters
- Red streaks spreading from the area
- Swollen glands nearby
- Feeling tired or sick
How it usually goes
- First 24 hours: Redness and swelling can spread quickly.
- 2 to 3 days on antibiotics: Redness should stop spreading and start to fade.
- 7 to 10 days: Most cases clear up.
When to get medical care
Causes
Cellulitis is caused by bacteria, most often group A strep or staph. They enter through a break in the skin.
Cuts, bites, burns, surgery wounds, bug bites, and cracked skin from athlete's foot or eczema are common entry points.
Does it spread or run in families?
- Yes, it can spread from person to person.
- How it spreads: cat, dog bites, scratches, or touch.
- Washing hands often and staying home when sick help protect others.
Who is more likely to get it
- Skin breaks or wounds
- Athlete's foot, eczema, or other skin conditions
- Long-term swelling in the arms or legs
- Diabetes or a weak immune system
- Past cellulitis
Possible complications
- Sepsis: Infection spreading in the blood
- Skin abscess: A pocket of pus under the skin
- Flesh-eating infection: A rare, deep, life-threatening infection
Diagnosis
A healthcare professional can usually tell it's cellulitis by looking at your skin. Lab tests often aren't needed.
Questions you may be asked
- When the redness started and how fast it's spreading
- Any cut, bite, scratch, or wound
- Fever, chills, or feeling sick
- Diabetes, leg swelling, or other health problems
- Past skin infections
The exam
They'll look at the area, check for pus, and feel for swollen glands nearby. They may draw a line around the red edge to see if it spreads.
Tests
For more serious infections:
- Blood tests: To check for infection in the blood.
- Wound culture: If there's pus, to find which germ is causing it.
- Ultrasound: To look for a pocket of pus (abscess) or a blood clot.
Treatment
Antibiotics are needed to treat cellulitis. Most people take pills at home.
Self-care
- Take every dose of your antibiotic, even when you feel better
- Raise the area above your heart to lower swelling and speed healing
- Rest until symptoms improve
- Mark the edge of the redness with a pen so you can tell if it spreads
- Keep any wound clean and covered
Medicines
Antibiotics need a prescription. Pain relievers can ease discomfort.
| Medicine | Helps with | Good to know |
|---|---|---|
| Antibiotics Penicillin V | Kills the bacteria | Tell your healthcare professional about allergies. Call if you get a rash, severe diarrhea, or aren't better in 2 to 3 days. |
| Pain relievers Acetaminophen, Ibuprofen | Pain and fever | Follow the label. |
If the infection may be MRSA (a staph germ that resists common antibiotics), a different antibiotic like co-trimoxazole may be used.
You may need IV antibiotics in a hospital if you're very sick, the infection spreads even with antibiotics, it's near your eye, or your immune system is weak. A pocket of pus may need to be drained.
How it compares
| Cellulitis | Skin abscess | Blood clot in the leg | Contact dermatitis | |
|---|---|---|---|---|
| Looks like | Red, warm, spreading area | Painful lump with pus | Swollen leg, may be red | Itchy red rash |
| Fever | Sometimes | Sometimes | Rarely | No |
| Main treatment | Antibiotics | Draining the pus | Blood thinners | Avoid the cause, creams |
Prevention
Good skin care lowers the risk:
- Wash cuts and scrapes with soap and water and keep them covered
- Treat athlete's foot and keep dry skin moisturized
- Check your feet daily if you have diabetes
- Watch any wound for redness, pain, or drainage
Which doctor treats this
- Start with your primary care provider (family doctor or internist).
- They may send you to a dermatologist (skin doctor).
Back to school, work, or sports
- Stay home until you've had no fever for 24 hours without fever medicine and you're feeling better.
- For the next 5 days, wash hands often and wear a mask around others.
Children, pregnancy, and older adults
- Babies: Call right away for any fever of 100.4°F or higher in a baby under 3 months.
- Diabetes: Foot infections can get serious fast. Check your feet every day.
- Repeat infections: If cellulitis keeps coming back below the knee, ask about checking for athlete's foot.
Pregnancy and breastfeeding
- If you're pregnant or planning to be, tell your prenatal provider about this condition.
- Some skin medicines, like isotretinoin and retinoid creams, aren't safe in pregnancy.
- Some infections can pass to the baby during pregnancy or birth. Tell your provider if you've been exposed.
- Don't start or stop any medicine on your own. Some are safe in pregnancy and some need to be changed.
- Ask before taking any pain reliever. The FDA advises avoiding ibuprofen and naproxen after 20 weeks unless your doctor says to.
- Breastfeeding: Most medicines are fine, but ask. The NIH LactMed database lists what's known about each one.
Outlook
Most cellulitis clears with 5 to 10 days of antibiotics. It can come back, especially if the cause, like athlete's foot or leg swelling, isn't treated.
Getting ready for your visit
Note when it started and how fast it grew.
What to bring
- Photos showing how the redness has changed
- A list of medicines and allergies
- Any recent cuts, bites, or surgery
Questions to ask
- Do I need pills or IV antibiotics?
- What signs mean it's getting worse?
- When should I feel better?
- How can I keep it from coming back?
Research studies
Research studies test new ways to find and treat health problems. Some are looking for volunteers. Talk with your doctor before joining one.
Sources
Last updated 2026-11-12.