Impetigo is a highly contagious bacterial skin infection.
Impetigo is caused by one or both of the following types of bacteria:
- Group A Streptococcus
These bacteria are normally found on the skin and in the nose. When small cuts, scratches, or insect bites occur, these bacteria can get under the skin surface and cause infection. Impetigo is often spread from person to person.
A risk factor is something that increases your chance of getting a disease or condition. Risk factors for impetigo include:
- Age: Preschool and school-aged children
- Touching a person with impetigo
- Touching the clothing, towels, sheets, or other items of 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
- Warm, humid environment
- Season: Summer
- Poor health or weakened immune system
- Tendency to have skin problems such as eczema, poison ivy, or skin allergy
- Cuts, scratches, insect bites or other injury or trauma to the skin
- Lice infections (like scabies, head or public lice), which cause scratching
Symptoms of impetigo appear 4-10 days after exposure.
Symptoms may include:
- Red spots, sores, or blisters, present on the skin of the face, arms, legs or other parts of the body, that:
- Ooze and become covered with a flat, dry, honey-colored crust
- May increase in size
- Spread, especially if scratched
- Swollen lymph nodes, in more serious cases
Normally, impetigo is a fairly mild condition. However, if left untreated, further problems could develop such as pain, swelling, spread of infection, discharge of pus, or fever. People whose impetigo is caused by Group A Streptococcus may in rare cases develop glomerulonephritis, scarlet fever, or life-threatening invasive streptococcal disease.
The doctor will examine your skin lesions and ask about your symptoms and medical history. Initial diagnosis is based on the appearance of your skin lesions. If you have impetigo, a culture of the skin lesion, if done, may show Streptococcus or Staphylococcus. A culture is usually not necessary except in severe or persistent infections.
The goals of treatment are to relieve the symptoms and cure the infection.
Treatment may include:
For a mild infection, a prescription topical antibiotic, such as mupirocin, or an over-the-counter topical antibiotic (significantly less effective), such as neomycin, bacitracin, or polymyxin, may be used and applied to the lesion. Otherwise, oral antibiotics, such as erythromycin and penicillin, may be prescribed. In many communities steptococcal infections can no longer by treated by erythromycin, so other medications may need to be used. Many forms of impetigo require medications like cloxacillin or cephalexin that are also active against many staphylococcal infections. In some cases, staphylococcal infections may be resistant to these antibiotics and others may be necessary.
Do not touch or scratch the lesions. The skin should be washed several times a day with soap and water or with an antibiotic soap. The crusts may be removed by soaking the infected area in warm water for about 15 minutes. Lesions should be covered loosely with gauze, a bandage, or clothing.
Avoiding Spread of the Infection
To help avoid spreading the infection:
- Wash your hands thoroughly, especially after touching an infected area of your body.
- Avoid contact with newborn babies.
- Stay home until 24 hours after the start of treatment.
- Do not handle food at home until a minimum of 24 hours after the start of treatment.
- If you work in the food service industry, ask your doctor when it is safe for you to return to work.
Prevention of impetigo involves good personal hygiene. The following tips can help:
- 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 after each time you touch the person.
- Do not share towels, clothes, or sheets, especially with a person who has impetigo.
- Keep fingernails short and clean.
- Change and wash clothing frequently.
- Do not let your children play or have close contact with someone who may have impetigo.
- Promptly wash wounds such as cuts, scratches, or insect bites, with soap and water. Consider applying a small amount of antibiotic ointment, and cover the wound with a bandage.