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skin abscess

An abscess is a collection of pus in, under or on the skin.

What is going on in the body?

An abscess usually forms in response to a bacterial infection, most commonly with Staphylococcus aureus. However, abscesses can also be a response to a foreign body under the skin. The body responds to either the bacteria or the foreign body by sending white blood cells to the area, which forms pus.

What are the signs and symptoms of the condition?

Abscesses usually cause tender, red, swollen skin with an overlying pus head. They can also appear as a very tender, soft lump in which the pus may not be visible.

What are the causes and risks of the condition?

Abscesses may form in response to:

• wounds or injuries to the skin, including surgery
• a foreign body under the skin, such as a splinter
• a sebaceous cyst, which is an oil-filled sac under the skin
• folliculitis, which is inflammation of a hair follicle
• furuncles, or boils

Risk factors for skin abscesses include the following:

• recent surgery
• diabetes
• recent chickenpox infection
• immunodeficiency disorder, in which the body's infection-fighting mechanisms are impaired. People with AIDS, for example, have a significant risk of skin abscess.
• impaired circulation, such as peripheral arterial disease, which limits blood flow to the legs and arms
• chronic use of certain steroids

What can be done to prevent the condition?

Prevention of a skin abscess starts with good hygiene. Any breaks in the skin, such as cuts, bites, or scratches, should be cleaned with soap and water before applying a bandage.

The area should be kept clean until the skin has healed over. Surgical wounds should be kept sterile, following the wound care instructions from the healthcare professional.

People with diabetes need to be especially careful with wounds to their feet or legs. Diabetes causes neuropathy, or nerve damage, which can result in a lack of feeling in the legs and feet.

Because a person with diabetes may not be aware of a foot injury, he or she should inspect the feet daily for any cuts or abnormal areas. Diabetes also causes poor circulation, which prevents wounds from healing as well as they would otherwise. A skin abscess is therefore more difficult to treat in people with diabetes.

How is the condition diagnosed?

The diagnosis of a skin abscess begins with a history and physical examination. The healthcare professional may collect a sample of pus from the abscess and send it to the laboratory so the organism can be identified.

What are the long-term effects of the condition?

A skin abscess can cause scarring and recurring lesions. Deep skin abscesses can spread and cause a blood infection known as sepsis. If the infection reaches the inside lining of the heart, particularly the valves, it is known as endocarditis. The abscess can also spread into underlying bones, causing the bone infection known as osteomyelitis.

What are the risks to others?

If the abscesses are caused by bacteria, the infection can be spread to others by skin-to-skin contact.

What are the treatments for the condition?

An incision and drainage (I & D) is generally done to drain the abscess of pus and foreign bodies. The healthcare professional makes a slit into the abscess and allows the pus to drain out. Packing may be left in the abscess for 24-48 hours to allow further drainage of pus.

Heat, such as a warm compress, and elevation of the area may be advised to reduce inflammation and speed healing. Antibiotics may be given to treat any bacterial infection. Over-the-counter pain medications may be taken as needed to relieve discomfort.

What are the side effects of the treatments?

Antibiotics and over-the-counter pain medications may cause upset stomach, rash, or allergic reactions. An incision and drainage may rarely cause bleeding, new infections, or a reaction to the local anesthetic.

What happens after treatment for the condition?

The skin abscess should completely vanish with effective treatment. Scars and recurrences are possible.

How is the condition monitored?

Any new or worsening symptoms should be reported to the healthcare professional.