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Diseases and Conditions
Special to CNN.com
If you have children, you've probably dealt with an assortment of rashes and skin irritations over the years. One of the most common of these is impetigo — a skin infection that mainly affects infants and children. Impetigo usually appears on the face, especially around a child's nose and mouth. And although it commonly occurs when bacteria enter the skin through cuts or insect bites, it can also develop in skin that's perfectly healthy.
Impetigo starts as a red sore that quickly ruptures, oozes for a few days and then forms a yellowish-brown crust that looks like honey or brown sugar. The disease is highly contagious, and scratching or touching the sores is likely to spread the infection to other parts of the body as well as to other people.
Impetigo is seldom serious, and minor infections may clear on their own in two to three weeks. But because impetigo can sometimes lead to complications, your child's doctor may choose to treat it with an antibiotic ointment or oral antibiotics. Your child can usually return to school or a child care setting as soon as he or she isn't contagious — often within 24 hours of starting antibiotic therapy.
You can help prevent the infection by taking good care of your child's skin. Use soap and water when bathing your child, and pay special attention to cuts, rashes, insect bites and allergic reactions. If anyone in your family does develop impetigo, a few simple measures can help keep the infection from spreading.
Signs and symptoms
Several types of impetigo exist, with differing signs and symptoms.
The most common form of impetigo is impetigo contagiosa, which usually starts as a red sore on your child's face, most often around the nose and mouth. The sore ruptures quickly, oozing either fluid or pus that forms a honey-colored crust. Eventually the crust disappears, leaving a red mark that heals without scarring. The sores may be itchy, but they aren't painful.
Your child isn't likely to have a fever with this type of impetigo but may have swollen lymph nodes in the affected area. And because it's highly contagious, just touching or scratching the sores can spread the infection to other parts of the body.
Bullous impetigo primarily affects infants and children younger than 2 years. It causes painless, fluid-filled blisters — usually on the trunk, arms and legs. The skin around the blister is usually red and itchy but not sore. The blisters, which break and scab over with a yellow-colored crust, may be large or small, and may last longer than sores from other types of impetigo.
Ecthyma is a more serious form of impetigo in which the infection penetrates deeper into the skin's second layer (dermis). Signs and symptoms include:
- Painful fluid- or pus-filled sores that turn into deep ulcers, usually on the legs and feet
- A hard, thick, gray-yellow crust covering the sores
- Swollen lymph glands in the affected area
- Scars that remain after the ulcers heal
Two types of bacteria cause impetigo — Staphylococcus aureus (staph), which is most common, and Streptococcus pyogenes (strep). Both types of bacteria can live harmlessly on your skin until they enter through a cut or other wound and cause an infection.
In adults, impetigo is usually the result of injury to the skin — often by another dermatological condition such as dermatitis. Children are commonly infected through a cut, scrape or insect bite, but they can also develop impetigo without having any notable damage to the skin. Impetigo that strikes healthy skin is called primary impetigo. Secondary impetigo occurs after an injury to your skin's protective barrier.
You're exposed to the bacteria that cause impetigo when you come into contact with the sores of someone who's infected or with items they've touched, such as clothing, bed linen, towels and even toys. Once you're infected, you can easily spread the infection to others.
Staph bacteria produce a toxin that causes impetigo to spread to nearby skin. The toxin attacks a protein that helps bind skin cells together. Once this protein is damaged, bacteria can spread quickly.
Although anyone can develop impetigo, children ages 2 to 6 years and infants are most often infected. Children are especially susceptible to infections because their immune systems are still developing. And because staph and strep bacteria flourish wherever groups of people are in close contact, impetigo spreads easily in schools and child care settings.
Other factors that increase the risk of impetigo include:
- Direct contact with an adult or child who has impetigo or with contaminated towels, bedding or clothing
- Crowded conditions
- Warm, humid weather — impetigo infections are more common in summer
- Participation in sports that involve skin-to-skin contact, such as football or wrestling
- Having chronic dermatitis, especially atopic dermatitis
Older adults and people with diabetes or a compromised immune system are especially likely to develop ecthyma, the most serious form of impetigo.
Screening and diagnosis
Doctors usually can diagnose impetigo by looking at the sores on a child's skin. Sometimes they use a cotton swab to gently remove a small bit of material from one of the sores. The material is sent to a lab where it's applied to a special medium (culture) to check for the presence of bacteria.
Impetigo typically isn't dangerous, but sometimes it may lead to rare but serious complications, including:
- Poststreptococcal glomerulonephritis (PSGN). This kidney inflammation may develop after a streptococcal infection such as strep throat or impetigo. It occurs when antibodies formed as a result of the infection damage the small structures (glomeruli) that filter waste in your kidneys. Although most people recover without any lasting damage, PSGN may lead to kidney failure. Signs and symptoms of PSGN commonly appear about two weeks after an infection. They include facial swelling — especially around the eyes — decreased urination, blood in the urine, high blood pressure and stiff or painful joints. Most often, PSGN affects children between the ages of 6 and 10 years. Adults who develop PSGN tend to have more serious symptoms than children do and are less likely to make a full recovery. Although antibiotics can cure strep infections, they don't prevent PSGN.
- Cellulitis. This potentially serious infection affects the tissues underlying your skin and eventually may spread to your lymph nodes and into the bloodstream. Left untreated, cellulitis can quickly become life-threatening.
- Methicillin-resistant Staphylococcus aureus (MRSA) infection. MRSA is a type of staph bacteria that resists most antibiotics. It can cause serious skin infections, which are extremely difficult to treat. The skin infection may start as a red, swollen pimple or boil that drains pus. MRSA may also cause pneumonia and blood infections.
Other complications include:
- Lightening (hypopigmentation) or darkening (hyperpigmentation) of the skin
How impetigo is treated depends on your child's age, the type of impetigo and the severity of the infection. Treatments include:
- Hygienic measures. Sometimes your doctor may choose to treat minor cases of impetigo with only hygienic measures. Keeping your child's skin clean can help mild infections heal on their own.
- Topical antibiotics. Your doctor may prescribe an antibiotic that you apply to your child's skin (topical antibiotic), such as mupirocin ointment (Bactroban). Topical antibiotics avoid side effects such as diarrhea that can result from some oral medications, but as with oral antibiotics, bacteria can become resistant to them over time.
- Oral antibiotics. Your doctor is likely to prescribe an oral antibiotic for ecthyma and severe cases of impetigo contagiosa. The specific antibiotic will depend on the severity of the infection and any allergies or conditions your child might have. Be sure to finish the entire course of medication even if your child seems better. This helps prevent the infection from recurring and makes antibiotic resistance less likely.
Keeping your child's skin clean is the best way to keep it healthy. Treat cuts, scrapes, insect bites and other wounds right away by washing the affected areas to prevent infection. If someone in your family already has impetigo, follow these measures to help keep the infection from spreading to others:
- Gently wash the affected areas with mild soap and running water and then cover lightly with gauze.
- Wash an infected child's clothes, linens and towels every day and don't share them with anyone else in your family.
- Wear gloves when applying any antibiotic ointment and wash your hands thoroughly afterward.
- Cut an infected child's nails short to prevent scratching.
- Encourage your child to wash his or her hands frequently.
- Keep your child home until your doctor says he or she isn't contagious.
For minor infections that haven't spread to other areas, try the following:
- Soak the affected areas of skin with a vinegar solution — 1 tablespoon of white vinegar to 1 pint of water — for 20 minutes. This makes it easier to gently remove the scabs.
- After washing the area, apply an over-the-counter antibiotic ointment three or four times daily. Wash the skin before each application, and pat it dry.
- Avoid scratching or touching the sores as much as possible until they heal. Applying a nonstick dressing to the infected area can help keep impetigo from spreading.