Definition

Impetigo is a skin infection. It often appears as blisters around the mouth and nose, but it can infect skin anywhere on the body. Impetigo can easily spread from one person to another. This infection occurs most often in children.

Impetigo: Sores on the Upper Lip Copyright © Nucleus Medical Media, Inc.

Causes

Impetigo is caused by bacteria. The most common type of bacteria associated with this infection includes:

• Group A streptococcus
• Staphylococcus

These types of bacteria are normally found on the skin and in the nose. The bacteria do not cause trouble until it gets under the skin. Bacteria get in under the skin through small cuts, scratches, or insect bites.

Risk Factors

This condition is more common in preschool and school-aged children.

Factors that may increase your chances of impetigo:

• Touching a person with impetigo
• Touching the clothing, towels, sheets, or other personal items that belong to a person with impetigo
• Poor hygiene, particularly unwashed hands and dirty fingernails
• Crowded settings where there is direct person-to-person contact such as schools and the military
• Contact sports such as football and wrestling
• Warm, humid environment
• Summer season
• Poor health or weakened immune system
• Tendency to have skin problems such as eczema, poison ivy, or a skin allergy
• Cuts, scratches, insect bites, or other injury to the skin
• Chickenpox
• Lice infections which cause scratching, such as scabies, head lice, or pubic lice

Symptoms

Symptoms of impetigo appear 4-10 days after contact with the bacteria.

The main signs of impetigo are skin lesions. They occur most often on the face, arms, or legs but can appear anywhere on the body. The lesions may be red spots, sores, or blisters. The lesion may:

• Ooze and become covered with a flat, dry, honey-colored crust
• Itch
• Increase in size
• Spread, especially if scratched

There may also be swollen lymph nodes in the area with more serious infections.

Impetigo is normally a fairly mild condition. However, further problems could develop if it is not treated. The infection could spread. This can lead to pain, swelling, pus, or fever. Rarely, impetigo that is caused by Group A streptococcus may develop into:

• Glomerulonephritis —damage to part of the kidney
• Scarlet fever —illness that may include a fever, sore throat, and widespread rash
• Life-threatening invasive streptococcal disease

Diagnosis

You will be asked about your symptoms and medical history. The skin lesions will be examined. Your doctor will be able to diagnose impetigo by the look of your skin lesions.

A sample of the infected skin may be tested. This will show what specific bacteria are causing the infection. It may help to guide treatment choices.

Treatment

The goals of treatment are to relieve the symptoms and cure the infection.

Treatment may include:

Prevention

Prevention of impetigo involves good personal hygiene:

• Bathe daily with soap and water.
• Wash your face, hands, and hair regularly.
• If caring for someone with impetigo, be sure to wash your hands each time you touch the person.
• Do not share towels, clothes, or sheets.
• Keep fingernails short and clean.
• Change and wash clothing often.
• Do not let your children play or have close contact with someone who may have impetigo.
• Wash wounds, such as cuts, scratches, or insect bites, with soap and water. Consider applying a small amount of antibiotic ointment. Cover the wound with a bandage.