What is cellulitis?

Cellulitis is a deep infection of the skin caused by bacteria. It usually affects the arms and legs. It can also develop around the eyes, mouth, and anus, or on the belly. Normal skin can be affected by cellulitis, but it usually 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 usually 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 allows the bacteria to enter. Other causes may include human or animal bites, or injuries that happen in water.

What are the symptoms of cellulitis?

Each person may experience symptoms differently. Common symptoms include:

• Redness of the skin
• Swelling of the skin
• Tenderness
• Warm skin
• Pain
• Bruising
• Blisters
• Fever
• Headache
• Chills
• Weakness
• Red streaks from the original site of the cellulitis

Some cases of cellulitis are an emergency. Always talk with your healthcare provider immediately if you notice any of the following symptoms:

• A very large area of red, inflamed skin
• Fever
• 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(s) or behind the ear(s)
• If you have diabetes or have a weakened immune system and develop cellulitis

The symptoms of cellulitis may look like other skin conditions. Always talk with your healthcare provider for a diagnosis.

How is cellulitis diagnosed?

Diagnosis is usually based on a medical history and physical exam. Blood and skin samples may be taken to confirm the diagnosis and the type of bacteria that is present. A bacterial culture can identify the organism causing the condition and indicate the most effective antibiotic.

How is cellulitis treated?

Your healthcare provider will consider your age, overall health and severity of the condition when determining the appropriate treatment for you.

Getting treated right away can help prevent the spread of cellulitis. Treatment may include:

• Oral, intramuscular (injection), or intravenous (IV) antibiotics
• Cool, wet dressings on the infection site
• Keeping the area dry and clean 
• Surgery
• If your arm or leg is affected, elevating the arm or leg may help
• Rest
• Time to heal 
• Topical antibiotics
• 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 intravenous (IV) catheter.

What are the complications of cellulitis?

Complications of cellulitis 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 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.
• 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?

If a wound begins to swell, turn red, feel warm, become painful, or the redness/warmth begins to spread from the wound, you should see your healthcare professional right away.

Key points about cellulitis

• Cellulitis is a deep bacterial infection of the skin.
• Cellulitis usually causes redness, swelling, and tenderness.
• Good hygiene 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.

Next steps

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.