Friday, December 02, 2005
Impetigo is an infection of the skin caused primarily by the bacterium Streptococcus pyogenes, also known as Group A beta-hemolytic streptococci (GABS). Sometimes another bacterium, Staphylococcus aureus, can also be isolated from impetigo lesions.
What are the symptoms of impetigo?
Impetigo begins as a cluster of small blisters that expand and rupture within the first 24 hours. The thin yellow fluid that drains from the ruptured blisters quickly dries forming a honey-colored crust. Impetigo develops most frequently on the legs, but may also be found on the arms, face and trunk. There is usually no fever.
How does a person get impetigo?
Impetigo may develop after the skin is infected with GABS. The bacterium is usually acquired from skin-to-skin contact with another person with impetigo. Less commonly, impetigo may develop when open skin lesions (such as insect bites or burns) are infected following exposure to a person with streptococcal pharyngitis ("strep throat").
Who gets impetigo?
The infection is most common in settings where there is crowding or activities leading to close person-to-person contact such as in schools and military installations. Impetigo occurs more commonly during the summer and early fall.
How long does it take to develop impetigo following exposure?
Impetigo may develop up to 10 days after the skin becomes infected with GABS.
How is impetigo treated?
Impetigo may be treated with an antibiotic taken by mouth or by application of an antibiotic ointment to the affected areas.
How long is a person considered infectious?
A person with impetigo is probably no longer infectious after 24 hours of adequate antibiotic treatment. Without treatment, a person may be infectious for several weeks.
What are the complications of impetigo?
Rarely, GABS may invade beyond the skin of a person with impetigo and cause more serious illnesses. Persons with impetigo may also develop post-streptococcal glomerulonephritis or scarlet fever. Post-streptococcal glomerulonephritis follows roughly 10 days after the onset of streptococcal infection and results in temporary kidney failure. However, the long-term prognosis is excellent. Scarlet fever is caused by a toxin produced by certain strains of GABS and is characterized by high fever, chills, sore throat, headache, vomiting and a fine red rash.
What can be done to prevent impetigo?
Simple cleanliness and prompt attention to minor wounds will do much to prevent impetigo. Persons with impetigo or symptoms of GABS infections should seek medical care and if necessary begin antibiotic treatment as soon as possible to prevent spread to others. Individuals with impetigo should be excluded from school, day care, or other situations where close person-to-person contact is likely to occur until at least 24 hours after beginning appropriate antibiotic therapy. Sharing of towels, clothing, and other personal articles should be discouraged.
Information provided by theWisconsin Department of Health and Family Services
Article Created: 2000-04-07Article Reviewed: 2000-04-07
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 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 your child's body.
Bullous impetigoBullous impetigo primarily affects children younger than two years and infants. It causes painless blisters — usually on the trunk, arms and legs. The blisters may be large or small and may last longer than sores from other types of impetigo. Bullous impetigo may cause other signs and symptoms, including:
Ecthyma is a more serious form of impetigo in which the infection penetrates deep 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
The usual cause of impetigo is the bacterium Staphylococcus aureus, although another bacterium, Streptococcus pyogenes (Group A beta-hemolytic streptococcus), may also cause or contribute to the condition. 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 following 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 yourself.
Staph bacteria produce a toxin that seems to make impetigo especially infectious. The toxin attacks a protein that helps bind skin cells together. Once this protein is damaged, germs can spread quickly.
Although anyone can develop impetigo, children ages 2 to 6 years and infants are most likely to become 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
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 diagnose impetigo simply by looking at the lesions on a child's skin. But sometimes they use a cotton swab to gently remove a small bit of material from one of the sores. This takes just a minute and shouldn't hurt. The material is then sent to a lab where it's grown on a special medium (culture) and checked for the presence of bacteria.
If you have a newborn with bullous impetigo, your baby is likely to be referred to a neonatologist for care.
Impetigo isn't dangerous, but sometimes it may lead to serious complications, including:
Poststreptococcal glomerulonephritis (PSGN).
This kidney inflammation may develop after a streptococcal infection such as strep throat or impetigo. It occurs when dead bacteria and antibodies become trapped in the small tubes that filter waste in your kidneys (glomeruli). Although most people recover without any lasting damage, PSGN can sometimes 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 boys between the ages of 3 and 7 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 clear up strep infections, they don't prevent PSGN.
This is a serious infection and inflammation of the memberanes and fluid surrounding your brain and spinal cord. Newborns with bullous impetigo are especially at risk. Meningitis usually starts suddenly with a high fever, severe headache and vomiting. As the disease progresses, the brain begins to swell and eventually to bleed. Without immediate treatment, children with meningitis may develop hearing loss, brain damage, blindness, learning disabilities and behavioral problems. The disease is fatal in about 10 percent of cases.
This potentially serious infection affects the tissues underlying your skin and eventually may spread to your lymph nodes and bloodstream. Left untrested, cellulitis can quickly become lifethreatening.
The treatments for impetigo may vary depending on your child's age, the type of impetigo and the severity of the infection.
Hygienic measures. Sometimes your doctor may choose to treat minor cases of impetigo with hygienic measures. Keeping your child's skin clean and bacteria-free can help mild infections heal on their own.
Topical antibiotics. In some cases, doctors 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 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 type of antibiotic will depend on the severity of the infection and any other 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 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. Regular use of antibacterial soaps may not be effective and can create antibiotic-resistant bacteria.
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 — one tablespoon of white vinegar to one 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 your skin before each application, and pat it dry.
Avoid scratching or touching the sores as much as possible until they heal. Applying a non-stick dressing to the infected area can help keep impetigo from spreading.