01 · Overview
The short version
It starts where bacteria get in
Cellulitis usually begins after bacteria enter through a bruise, burn, surgical cut, wound, or other break in the skin.
Redness that spreads matters
The usual pattern is painful, red, tender skin that can swell, feel warm, and spread wider over time.
Antibiotics are the main treatment
Mild cases may be treated with antibiotics by mouth. More severe cases may need IV antibiotics and closer monitoring.
Eye-area infections need special care
Redness, swelling, pain, or vision problems around the eye can signal a more urgent infection and should be evaluated promptly.
02 · Care guidance
When to get help
Emergency help
- Call 911 or go to the emergency department now if the redness is spreading very fast and you also have trouble breathing, confusion, fainting, severe weakness, or signs of sepsis such as high fever with rapid heart rate and feeling extremely ill.
- Seek emergency care right away for cellulitis near the eye with eye pain, trouble moving the eye, bulging of the eye, or vision changes.
- Get urgent help for sudden severe pain, purple or black skin, blistering with fast worsening, or pain that seems much worse than the skin changes.
Get advice promptly
- Contact a clinician promptly if you think you have cellulitis, especially if the area is enlarging, is on the face or hand, or if you have fever, diabetes, poor circulation, immune suppression, or a bite, wound, or surgery site that is getting worse.
- Call soon if you are already on antibiotics and the area is not improving within about 24 to 48 hours, or if it is becoming more painful, swollen, or tender.
If the redness is mild and you are otherwise well, arrange an in-person visit or urgent care evaluation the same day or next day. Mark the edge of the redness with a pen and take photos so the clinician can compare changes.
03 · Cellulitis
What cellulitis actually is
Cellulitis is a bacterial infection in the skin and deeper tissue, not just a surface rash.
Cellulitis starts when bacteria get past the skin’s protective barrier and into the skin and the tissue underneath it. A cut, scrape, bruise, burn, surgical incision, or wound can give the bacteria a way in. That is why an apparently small break in the skin can matter so much.
The area often becomes red, warm, tender, and swollen. It may look tight or shiny, and the red patch can expand. Cellulitis can happen anywhere, but it often shows up on the legs. The main concern is that it can keep spreading if it is not treated.
- A break in the skin is often the starting point.
- The redness is usually painful or tender, not just itchy.
- Expansion over hours or days is a warning sign.
04 · Cellulitis
The signs that make cellulitis more likely
Spreading redness with warmth, swelling, and tenderness is the classic pattern.
The most typical symptoms are a red patch of skin that hurts, feels warm, and becomes swollen or tender. Some people also notice swollen glands or lymph nodes near the affected area. The skin can blister or scab in some cases.
Fever and chills make the infection more concerning because they can mean the body is reacting more strongly. Symptoms can look different depending on where the infection is, how long it has been there, and whether another problem, such as an abscess, is also present.
- Pain, warmth, swelling, and tenderness are common.
- Fever, chills, or swollen glands add concern.
- Blistering or scabbing can happen in some cases.
05 · Cellulitis
How clinicians decide it is cellulitis
Diagnosis is usually based on the exam and the way the redness has changed over time.
There is no single test that proves cellulitis in every case. Clinicians usually diagnose it by looking at the skin, asking how quickly it changed, and checking for a recent injury, wound, fever, or other clue that bacteria may have entered through broken skin.
They also look for problems that can look similar but need different treatment. An abscess, for example, can sometimes need drainage instead of antibiotics alone. If the area is on or near the eye, the evaluation needs extra care because infections there can become urgent.
- The history of how fast it changed is important.
- An abscess can change the treatment plan.
- Eye-area swelling deserves special attention.
06 · Cellulitis
Why antibiotics are usually needed
Cellulitis is treated with antibiotics, and more severe cases may need IV medicine and closer monitoring.
Antibiotics are the main treatment for cellulitis. Mild cases may be treated with medicine taken by mouth, while more severe cases may need IV antibiotics in a medical setting. The type of treatment depends on how sick the person is and how quickly the infection is moving.
Treatment can also include care for the original wound, pain relief recommended by a clinician, and elevating the affected arm or leg to help with swelling. If there is pus or an abscess, drainage may be needed because antibiotics alone may not solve the problem.
- Oral antibiotics may be enough for mild cases.
- Fast-spreading or severe cases may need IV treatment.
- Do not try to drain or squeeze a possible abscess at home.
07 · Cellulitis
How to lower the chance of another episode
Protecting the skin barrier is the main way to reduce future infections.
Cellulitis often starts where the skin has already been damaged, so skin care matters. Wash minor cuts, keep wounds covered when needed, and pay attention to cracks, bites, burns, or areas that are slow to heal. If you have athlete’s foot or another skin condition that breaks the skin, treating it early can help lower risk.
If you have repeated episodes, the goal is not only to treat each one but also to find out why the skin keeps opening up. A clinician may look for ongoing swelling, poor circulation, diabetes, or another problem that makes infection more likely.
- Clean and cover small wounds.
- Treat skin problems that crack or peel the skin.
- Get checked if infections keep coming back.
08 · Cellulitis
When cellulitis becomes urgent
Fast spread, severe pain, or eye symptoms can mean a dangerous infection.
Cellulitis can become more serious if it spreads quickly or reaches the bloodstream. Fever, rapid worsening, confusion, fainting, severe weakness, or a person who feels very ill are warning signs that the infection may be affecting more than the skin.
The eye area needs extra caution. Eyelid or nearby skin infections can sometimes spread behind the eye, and that can threaten vision. A painful, swollen eye area, trouble moving the eye, bulging, or vision changes should be treated as urgent.
- Rapid worsening can point to a more serious infection.
- Purple or black skin and blistering are emergency signs.
- Eye pain or vision changes need immediate attention.
09 · FAQ
Questions people ask
Why does cellulitis happen after such a small cut?
Even a tiny break in the skin can let bacteria in, especially if the area is scraped, burned, contaminated, or slow to heal. The skin is supposed to block germs, so once that barrier is damaged, deeper tissue can become infected.
Is cellulitis contagious?
Cellulitis itself is not usually spread from person to person like a cold. The bacteria can still be present in a wound, though, so handwashing and proper wound care still matter.
Does itching mean it is not cellulitis?
No. Itching can happen with many skin problems, including rashes and some infections. Cellulitis is more often painful, warm, and swollen, but symptoms can overlap, so a growing or tender area should be checked.
What if the redness is on my face?
Face cellulitis should be checked promptly because infections there can spread and may involve the area near the eyes. If there is eye pain, vision change, swelling around the eye, or trouble moving the eye, seek urgent care right away.
How soon should antibiotics help?
Some people start to feel better within a couple of days, but redness and swelling can take longer to settle. If the area is clearly getting worse, or there is no improvement after starting prescribed treatment, contact the clinician who is treating you.
Should I draw a line around the redness?
Yes, that can help you see whether it is spreading. Use a pen or marker to trace the edge and note the date and time. If the redness moves past the line quickly, get medical advice promptly.
10 · References
References and supporting evidence
These sources support the points identified below. Source checking is not clinical approval.
- S1: CellulitisMedlinePlus / U.S. National Library of Medicine
Explains what cellulitis is and that bacteria cause it; also supports that the infection affects deeper skin tissue. Explains the usual entry point through broken skin and gives examples such as burns, cuts, and wounds. Explains common symptoms such as painful red tender skin, fever, chills, and swollen lymph nodes. Supports mention that blistering or scabbing can occur in some cases. Explains that clinicians may use skin samples, cultures, or blood tests in some cases. Supports that antibiotics are the main treatment and that route depends on severity.
- S2: Eye InfectionsMedlinePlus / U.S. National Library of Medicine
Supports eye-area warning signs such as pain, swelling, and vision problems needing prompt attention.
- S3: Eyelid DisordersMedlinePlus / U.S. National Library of Medicine
Supports the warning that infection around the eye can become urgent and needs immediate care if it spreads deeper.
General information, not a diagnosis. This guide is not a substitute for care from a qualified healthcare professional. For an emergency, call 911 in the US or your local emergency number. Illustrations are conceptual and are not diagnostic images.