Paul wasn't too surprised when he got a case of poison ivy after a weekend camping trip — he'd had that problem before. But this time it was different. On parts of his arms where the rash had first appeared, he soon developed new kinds of blisters that oozed and then crusted over.
After a visit to the doctor, Paul learned that he had more than poison ivy. He also had a skin infection called impetigo.
Impetigo is a skin infection typically caused by one of two bacteria: Staphylococcus aureus (S. aureus) or Streptococcus pyogenes (also called group A streptococcus and the same bacteria that cause strep throat). Methicillin-resistant Staphylococcus aureus (also known as MRSA) bacteria are also becoming an important cause of impetigo.
Impetigo can affect skin anywhere on the body but often affects the area around the nose and mouth. It is more likely to show up on skin that is already irritated or raw from eczema, poison ivy, cut or scrape, or an insect bite.
Touching the infected skin and then touching another part of the body can spread the infection to that spot. It also can be spread to someone else if another person touches the infected area. Because kids in preschool and elementary school have lots of close contact with other kids, impetigo occurs most commonly in them, but anyone can get it.
Tiny blisters are usually the first symptom of impetigo. The blisters can be caused by S. aureus or group A strep. When the blisters burst, the skin underneath them is moist, red, and may ooze fluid. Next, a tan or yellow-brown crust covers the wet areas, making it look like they've been coated with honey or brown sugar.
S. aureus infection also can cause larger blisters filled with fluid that starts out clear but then becomes cloudy. These blisters usually remain whole without bursting for a longer time. It can be difficult to tell if a case of impetigo is caused by strep or staph bacteria. But the treatment is similar, no matter which type of bacteria caused the infection.
Doctors usually diagnose impetigo based on how it looks and treat the infection with antibiotics. Your doctor probably will prescribe an antibiotic ointment if the infection is mild. If the impetigo has spread to a few places, or if the ointment isn't working, you may need to take an antibiotic pill. It's important to finish all of the medicine prescribed even if the spots clear up quickly.
Because impetigo can spread from person to person through contact with the infected area, the sores should be kept covered. If this isn't possible, staying home from school for a day or two while the rash is still contagious might be a good idea. After 3 days of treatment, it should start to heal and scab over.
If your skin doesn't begin to heal after this time or if you develop a fever, call your doctor again. You also should let your doctor know right away if skin around the impetigo becomes red, warm, swollen, or tender.
Besides taking or applying your medicine exactly as your doctor directed, you can gently wash the infected areas with unscented soap and water, using a piece of clean gauze. If a spot is crusted, soak it in warm, soapy water for a while to remove built-up layers of the crust. You do not need to get rid of all of the crust, but it is important to keep the area clean.
To avoid spreading impetigo to other parts of the body, cover the infected areas with gauze and tape or a loose plastic bandage.
Also consider keeping your fingernails short until the infection clears up to help you resist scratching. Impetigo can itch, but try not to scratch because it can spread the infection or tear the skin and make it worse. Scratching repeatedly can lead to scarring of the skin.
If the itching continues, ask your mom or dad about taking an anti-itching medication like diphenhydramine. This could get you over the hump and prevent further scratching.
The best way to prevent impetigo is to follow good hygiene practices. Take a bath or shower regularly and use soap to keep your skin clean. Watch for skin that is injured or irritated — including cuts, scrapes, bug bites, areas of eczema, and rashes — and keep these areas clean and covered.
If someone in a family has impetigo, that person should cover the sores to prevent the infection from spreading to others in the house and should not share clothing, towels, razors, or bed linens with anyone else. When they get dirty, wash these items separately in very hot water. Using paper towels instead of cloth towels also can help keep the infection from spreading to others. Sharing makeup is never a good idea but even more risky if you have impetigo.
Reviewed by: Yamini Durani, MD
Date reviewed: May 2011
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