Cellulitis is a common condition that can occur anywhere on the body, but it often involves the lower leg and usually just one side of the body.

Cellulitis symptoms include:

• Swelling.
• Warmth.
• Pain.
• Fever.
• Chills.
• Spots on the skin.
• Blisters.
• Skin dimpling.

It's important to find and treat cellulitis early because the condition can spread rapidly throughout the body.

Seek emergency care if:

• You have a swollen rash or a rash that's changing rapidly.
• You have a fever.

See a healthcare professional within 24 hours if you have a swollen rash or a rash that's growing but you don't have a fever.

Cellulitis happens when bacteria enter the body through a crack or break in the skin. Bacteria are most likely to enter broken, dry, flaky or swollen skin. Examples of entry points for bacteria are a recent surgical site, a cut, a puncture wound, a sore, and skin affected by athlete's foot or dermatitis. Cellulitis usually isn't spread from person to person.

The most common bacteria with this condition are streptococcus and staphylococcus. The incidence of a more serious staphylococcus infection called methicillin-resistant Staphylococcus aureus (MRSA) is increasing.

Several factors put you at increased risk of cellulitis:

• Injury. Any cut, fracture, burn or scrape gives bacteria an entry point.
• Weakened immune system. Conditions that weaken the immune system increase the risk of infection. Examples are diabetes, leukemia and HIV/AIDS. Certain medicines also can weaken the immune system.
• Skin conditions. Conditions such as atopic dermatitis — also called eczema — athlete's foot and shingles can cause breaks in the skin and give bacteria an entry point.
• Long-term swelling of the arms or legs. This condition is called lymphedema. It sometimes happens after surgery.
• History of cellulitis. Having had cellulitis before increases the risk of getting it again.
• Being overweight. Excess weight increases the risk of developing cellulitis.

Untreated cellulitis might lead to serious conditions such as bacteremia, endocarditis, osteomyelitis, toxic shock syndrome or sepsis. Rarely, the infection can spread to the deep layer of tissue called the fascial lining. Necrotizing fasciitis is an example of a deep-layer infection. It's an extreme emergency.

Repeated episodes of cellulitis may cause the lymph nodes to enlarge. This can cause long-term swelling of the affected limb.

If you tend to have repeated episodes of cellulitis, your healthcare professional may recommend taking antibiotic medicine to prevent it from coming back.

To help prevent cellulitis and other infections, take these precautions when you have a skin wound:

• Wash the wound daily with soap and water. Do this gently as part of your regular bathing.
• Ask your healthcare professional whether it would help to apply cream or ointment. For most minor wounds, the products you can buy without a prescription provide good protection. One example is petroleum jelly (Vaseline).
• Cover the wound with a bandage. Change bandages at least daily.
• Watch for signs of infection. Irritation, pain and pus all signal possible infection and the need for medical care.

People with diabetes or poor circulation need to take extra care to prevent skin injury. Good skin care includes the following:

• Inspect your feet daily. Check your feet for signs of injury so that you can catch infections early.
• Moisturize your skin at least once a day. This helps prevent the skin from cracking and peeling. Don't apply moisturizer to open sores.
• Trim your fingernails and toenails with care. Try not to cut the surrounding skin.
• Protect your hands and feet. Wear footwear and gloves suitable to your activities.
• Treat athlete's foot and toenail fungal infections as soon as they occur.

Your healthcare professional will likely be able to diagnose cellulitis by looking at your skin. You might need to have blood tests or other tests to help rule out other conditions.

Cellulitis treatment usually includes a prescription antibiotic medicine taken by mouth. You take it for as long as your healthcare professional directs, usually 5 to 10 days, even after you feel better. Symptoms typically disappear a few days after you start treatment.

You may need to be hospitalized and receive medicine through your veins if:

• Symptoms don't respond to the medicine taken by mouth.
• Symptoms are extensive.
• You have a high fever.

Try these steps to help ease any pain and swelling:

• Place a cool, damp cloth on the affected area as often as needed for your comfort.
• Ask your healthcare professional to suggest a nonprescription pain medicine.
• Elevate the affected part of the body.
• Ask your healthcare professional whether it might help to wear compression wraps or stockings.

You're likely to start by seeing your primary health professional, who may refer you to a doctor who specializes in skin disorders. This type of doctor is a dermatologist. If you have a serious infection, an emergency room healthcare professional may examine you first. You also may be referred to an infectious disease specialist.

Here's some information to help you get ready for your appointment.

What you can do

Make a list of:

• Your symptoms, including any that may seem unrelated to the reason for which you scheduled the appointment.
• Key personal information, such as if you've had any recent surgeries, injuries or bites.
• Medicines, vitamins and supplements you're taking and the dosages.
• Questions to ask your healthcare professional.

Preparing a list of questions can help you make sure that you cover the points that are important to you. For cellulitis, some basic questions to ask your healthcare professional include:

• How might I have gotten this infection?
• What tests do I need? Do these tests require special preparation?
• How is cellulitis treated?
• How soon will the treatment start working?
• What side effects are possible with this medicine?
• I have other medical conditions. How do I manage them together?
• Are there alternatives to antibiotics?
• Is there a generic alternative to the medicine you're prescribing?
• How can I prevent this type of infection in the future?
• Do you have any brochures or other printed material that I can have? What websites do you recommend?

Don't hesitate to ask other questions you have.

What to expect from your doctor

Your healthcare professional is likely to ask you questions such as:

• When did your symptoms start?
• Do you remember injuries or insect bites to that area?
• How severe is the pain?
• Does anything seem to improve your symptoms?
• Are you allergic to or intolerant of any antibiotics?
• Have you had this type of infection before?

What you can do in the meantime

You may need a prescription antibiotic to clear your infection. However, until you see your healthcare professional, you can wash the injured area with soap and water and place a cool, damp cloth over it.