Impetigo is a highly contagious skin infection. It is caused by bacteria.
Impetigo: Sores on the Upper Lip
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. There they can cause infection. Impetigo is often spread from person to person.
Factors that increase your chance 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
- Seasonal: 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 lice]]> , 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. This can include pain, swelling, spread of infection, discharge of pus, or fever. In rare cases, people whose impetigo is caused by Group A Streptococcus may develop:
The doctor will examine your skin lesions. Your doctor will also 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 may be done. This will show what specific bacteria are involved.
The goals of treatment are to relieve the symptoms and cure the infection.
Treatment may include:
For a mild infection:
- Prescription topical antibiotic (eg mupirocin]]> , ]]>retapamulin]]> )
- Over-the-counter topical antibiotic (significantly less effective), such as neomycin, ]]>bacitracin]]> , or polymyxin
Your doctor may prescribe oral antibiotics, such as:
- A penicillin
In some cases, staphylococcal infections (eg, ]]>MRSA]]> ) may be resistant to these antibiotics. Others options may be needed.
Do not touch or scratch the lesions. The skin should be washed several times a day. Use soap and water or 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. This is more important 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.
American Academy of Dermatology
Kid's Health for Parents (Nemours Foundation)
Canadian Dermatology Association
American Osteopathic Association website. Available at: http://www.osteopathic.org/ .
Koning S, van der Wouden JC, Chosidow O, Twynholm M, Singh KP, Scangarella N, Oranje AP. Efficacy and safety of retapamulin ointment as treatment of impetigo: randomized double-blind multicentre placebo-controlled trial. Br J Dermatol . 2008;158(5):1077-82.
Maryland Department of Health and Mental Hygiene website. Available at: http://www.dhmh.state.md.us/ .
Nebraska Health and Human Services System website. Available at: http://www.hhs.state.ne.us/ .
Last reviewed January 2009 by ]]>Ross Zeltser, MD]]>
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.
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