Impetigo is a bacterial skin infection that is characterized by blisters that may itch.
Impetigo commonly occurs when bacteria enter the skin through cuts, scrapes or insect bites, but sometimes it affects perfectly healthy skin. It 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. Impetigo 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 2 to 3 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. If so, healing should begin in about 3 days. Most often, your child can return to school or a child-care setting as soon as he or she isn't contagious — usually within 24 hours of starting antibiotic therapy.
You can help prevent impetigo by taking good care of your child's skin. When you bathe your child, use soap and water and pay special attention to cuts, rashes, insect bites and allergic reactions, such as those from poison oak or poison ivy. If anyone in your family does develop impetigo, a few simple measures can help keep the infection from spreading.
Signs and symptoms
Impetigo occurs in several types, each with its distinctive characteristics:
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 the infection is extremely contagious, just touching or scratching the sores can cause it to spread to other parts of your child's body.
Impetigo is usually caused by 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 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:
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
See your doctor if your child develops any unusual sores, especially if they contain fluid or pus. Although impetigo isn't dangerous, it may lead to serious complications when it's not treated or controlled.
Your pediatrician will usually diagnose the infection simply by looking at the lesions on your child's skin. But sometimes he or she may 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.