Cellulitis is a serious deep infection of the skin caused by bacteria. It often occurs in an area that has already had an injury or skin break.
The Medical Dermatology Program at Massachusetts General Hospital is a full-service dermatology practice that provides care for all skin, hair and nail conditions.
What is cellulitis?
Cellulitis is a deep infection of the skin caused by bacteria. It often affects the arms and legs. It can also develop around the eyes, mouth, and anus, or on the belly (abdomen). Normal skin can be affected by cellulitis. But it often happens after some type of injury causes a skin break, including trauma or surgery. Once the skin breaks, bacteria can enter and cause infection.
What causes cellulitis?
Cellulitis is often caused when bacteria enter a wound or area where there is no skin. The most common bacteria that cause cellulitis include:
Group A ß - hemolytic streptococcus (Strep)
Streptococcus pneumoniae (Strep)
Staphylococcus aureus (Staph)
Staph and strep bacteria are commonly found on the skin and mucous membranes of the mouth and nose in healthy people. The infection happens when there is a break in the skin that lets the bacteria enter. Other causes may include human or animal bites, or injuries that happen in water.
What are the symptoms of cellulitis?
Symptoms can be different for each person. Common symptoms include:
Red streaks from the original site of the cellulitis
Some cases of cellulitis are an emergency. Always talk with your healthcare provider right away if you notice any of the following symptoms:
A very large area of red, inflamed skin
If the area affected is causing numbness, tingling, or other changes in a hand, arm, leg, or foot
If the skin appears black
If the area that is red and swollen is around your eye or behind the ear
If you have diabetes or have a weak immune system and get cellulitis
Many of these symptoms can be caused by other skin conditions. Always talk with your healthcare provider for a diagnosis.
How is cellulitis diagnosed?
Diagnosis is often based on a health history and physical exam. Blood and skin samples may be taken to confirm the diagnosis and the type of bacteria present.
A bacterial culture can sometimes identify the organism causing the condition. This helps guide treatment with the correct antibiotic.
How is cellulitis treated?
Your healthcare provider will consider your age, overall health, and severity of the condition when finding the best treatment for you.
Getting treated right away can help prevent the spread of cellulitis. Treatment may include:
Antibiotics, which can be given by mouth (oral), shot (injection), or by IV (intravenously)
Keeping the area clean and applying dressings as instructed
If your arm or leg is affected, raising (elevating) the arm or leg may help
Time to heal
Pain medicine as needed
Based on the physical exam, your healthcare provider may treat you in the hospital, depending on the severity of the cellulitis. In the hospital, you may get antibiotics and fluids through an IV.
What are possible complications of cellulitis?
In most cases, cellulitis is easily treated with no complications. But in some cases complications can be very serious. These can include extensive tissue damage and tissue death (gangrene). The infection can also spread to the blood, bones, lymph system, heart, or nervous system. These infections can lead to removing the affected arm or leg (amputation), shock, or even death.
Can cellulitis be prevented?
To prevent cellulitis:
Use good personal hygiene.
Wash hands often.
Apply lotion to dry, cracked skin.
Use gloves when cuts and scrapes may happen.
Never go barefoot, always wear protective footwear.
If skin breaks happen, keep the area clean and use an over-the-counter antibiotic ointment. Watch for signs of infection. If you have diabetes, visually check your feet for signs of skin breaks or infection. Also, don’t cut out warts or calluses, and don’t cut toenails too short.
When should I call my healthcare provider?
Call your healthcare provider right away if a wound starts to swell, turn red, feel warm, or get painful. Also call if the redness or warmth starts to spread from the wound.
Key points about cellulitis
Cellulitis is a deep bacterial infection of the skin.
It often causes redness, swelling, and soreness.
Good hygiene, protective footwear, and skin care can help prevent cellulitis.
Watch any breaks in the skin for signs of infection.
Untreated cellulitis can lead to amputation, shock, and even death.
Tips to help you get the most from a visit to your healthcare provider:
Know the reason for your visit and what you want to happen.
Before your visit, write down questions you want answered.
Bring someone with you to help you ask questions and remember what your provider tells you.
At the visit, write down the name of a new diagnosis, and any new medicines, treatments, or tests. Also write down any new instructions your provider gives you.
Know why a new medicine or treatment is prescribed, and how it will help you. Also know what the side effects are.
Ask if your condition can be treated in other ways.
Know why a test or procedure is recommended and what the results could mean.
Know what to expect if you do not take the medicine or have the test or procedure.
If you have a follow-up appointment, write down the date, time, and purpose for that visit.
Know how you can contact your provider if you have questions.
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