Impetigo

Impetigo is a common and highly contagious skin infection that most often occurs in children. In fact, it is the most common skin infection among children. Adults who contract impetigo usually get it from contact with children.

Impetigo is caused by toxin-producing bacteria that may normally be present on the skin. Unbroken skin usually provides a barrier to prevent bacteria from entering the body. However, any break in the skin, from a cut or skin disease, may permit the bacteria to enter and inflame the layers of skin. Environmental changes, including warmer weather, may also provide more opportunities for the bacteria to affect the body.

Impetigo usually produces sores on the face and around the mouth. They may begin as a single sore and spread to form others that ooze pus and form a crust. These lesions may itch, but are not typically painful.

Impetigo-related lesions are extremely contagious. Touching one sore and then touching another body part can spread the infection. It may also spread from clothing or towels that came into contact with a sore.

People at risk for impetigo include:

• Those with underdeveloped or weakened immune systems, especially children and patients with chronic illnesses (e.g., diabetes).
• Patients on antibiotic therapy. Prolonged use of antibiotics can lower a person's ability to fight infection.

Impetigo is seldom serious, especially if treated early. It can be treated with topical antibiotic ointment or oral medications. The sores usually clear up within a few weeks, although sometimes scarring can occur.  In rare circumstances, impetigo infection can lead to complications in other parts of the body, including the kidneys. About impetigo
Impetigo is a highly contagious skin condition, and is the most common skin infection that affects children. It is caused by either the Staphylococcus aureus (staph) or Streptococcus pyogenes (strep) bacteria, and sometimes a combination of the two. Adults also get impetigo, frequently from contact with infected children.

The skin normally has many harmless types of bacteria living on it, known collectively as the skin flora. These bacteria live in the skin's hair follicles and in sebaceous glands that moisten the skin. They also protect the body from more harmful bacteria. The skin itself also provides a major barrier to keep both the bacteria in the skin flora and other harmful organisms from entering the body. However, when there is a break in the skin (e.g., from a cut, bruise or other form of trauma), bacteria can enter the body and cause inflammation and infection. Other factors may also affect the skin flora and make it susceptible to infection, including high temperatures or humidity, pre-existing skin infections and prolonged use of antibiotics, which can lower a person's ability to fight infection.   

When impetigo occurs, bacteria enter the skin's outer layer (epidermis) and form skin lesions that may ooze and form crusts. These lesions are extremely contagious. Touching, rubbing or scratching them often leads to their spread to other parts of the body.

Typically, impetigo is acquired by direct skin-to-skin contact with an infected person. People can also become infected through contact with infected objects (e.g., utensils, clothes, toys, doorknobs). Children pass it during contact at school or while playing. Impetigo is more common in warmer weather and tropical climates. It occurs more readily in crowded conditions and in areas where there is inadequate hygiene.

Most cases of impetigo occur among children between 2 and 6 years old, although a less common form occurs among infants.

Impetigo is seldom serious, especially if treated early. The lesions clear up within a few weeks, although scarring can sometimes occur. In a few rare cases, impetigo can spread to other parts of the body and lead to complications. These may include:

• Cellulitis. An infection affecting the tissues underneath the skin that spreads to the lymph nodes and bloodstream.
• Post-streptococcal glomerulonephritis. A rare complication of impetigo resulting in inflammation of the kidneys, which may lead to kidney failure.

Types and differences of impetigo
There are two major types of impetigo:

• Nonbullous impetigo. This form of impetigo – also called impetigo contagiosa – is the most common form. It is usually caused by either the Staphylococcus aureus (staph) or Streptococcus pyogenes (strep) bacteria, or a mix of the two. Infection typically occurs at sites of trauma to the skin, such as a chickenpox sore, insect bite, cut or other laceration that results in a break in the skin. Specifically, these bacteria attack a protein that helps bind skin cells together. When this protein is damaged, the bacteria invade and establish infection in the skin. This form of impetigo usually occurs among children between 2 and 6 years of age, often during warmer months.

  Ecthyma is a rare form of nonbullous impetigo that penetrates deep into the skin's second layer (dermis). The streptococcal bacterium is the most common infectious organism associated with ecthyma. The infection may begin at the site of an injury, such as a scratch or insect bite, and often affects the legs.

• Bullous impetigo. This form of impetigo is caused by the staph bacteria. In contrast to the nonbullous form, bullous impetigo results from invasion by only staph bacteria into either intact or broken skin. Infection usually occurs after the bacteria colonize the upper respiratory tract, usually the nostrils. Bullous impetigo is much less common than nonbullous impetigo and may occur in infants.

Risk factors and causes of impetigo
Impetigo is caused by common bacteria that may be naturally present on the skin. It usually affects children and can spread rapidly wherever groups of children are in close contact, such as in schools and childcare settings. Risk factors for developing impetigo include:

• Direct skin-to-skin contact with a person who has the disease or with contaminated objects (e.g., towels, bedding, clothing). Blisters typically appear within four to 10 days after coming into contact with fluids from the lesions of an infected person.
• Minor cuts, wounds, burns and/or other trauma that causes a break in the skin.
• Weakened immune system. People suffering from diseases that weaken the immune system, such as diabetes, may be more prone to becoming infected. In addition, prolonged use of antibiotics may weaken the immune system.
• Warm, humid weather. High temperature causes a disruption in the skin's natural flora (harmless bacteria) and may predispose it to infection from bacteria.
• Chronic skin diseases (e.g., eczema).
• Crowded conditions, especially places where there is poor hygiene.

Impetigo occurs when the toxins produced by either the Staphylococcus aureus (staph) or Streptococcus pyogenes (strep) bacteria, or a combination of the two, enter the skin. The staph and strep bacteria are often present in the nose or on the skin and are generally harmless in those locations. When they enter the skin, however, the bacteria attack a protein that helps bind skin cells together. After this protein is damaged, germs can spread quickly and infection begins.Signs and symptoms of impetigo
The most common symptom of impetigo is lesions on the skin. The specific appearance of the skin and any other symptoms may differ slightly, depending on the type of impetigo present.

Symptoms of nonbullous impetigo may include:

• Painless skin lesions on the face, most often around the nose and mouth, which quickly spread to other areas of the body if a person touches or scratches them. Typically the lesion begins as a cluster of tiny blisters that burst, followed by oozing and the formation of a thick honey- or brown-colored crust on the skin.
• Itchiness (pruritus) on the affected areas.
• Swollen lymph nodes.

Ecthyma, the more involved form of nonbullous impetigo, may involve painful fluid- or pus-filled sores that turn into deep ulcers, usually in the legs and feet. A hard, thick, gray-yellow crust forms over the ulcers. Unlike other forms, ecthyma ulcers may leave scars.

Symptoms of bullous impetigo may include:

• Painless blisters filled with yellow pus that vary in size and rupture easily. Lesions commonly appear on the face, trunk, arms and legs. When the blisters rupture, they leave behind shiny, varnish-like erosions without thick crusts.
• Fever.
• Diarrhea.
• Fatigue.

Diagnosis and treatment options for impetigo
In most cases, impetigo can be diagnosed based on a visual examination of the lesions and patient symptoms. A physician will perform a complete physical examination and compile a thorough medical history when trying to make a diagnosis. If a newborn is suspected of having the disease, a physician may refer the baby to the care of a neonatologist, a physician who specializes in the medical treatment of newborn infants.

In cases where diagnosis is unclear after examination, a physician may perform a punch biopsy to obtain a sample of the lesion and/or fluid for microbiological analysis. In rare cases, a blood test may be performed to determine if the infection has spread to other parts of the body.

In mild cases of impetigo, the infection may clear up on its own in a few weeks. However, medications may be necessary to cure the infection, especially in severe cases where the lesions have spread. Physicians generally prescribe topical or oral antibiotics, or a combination of the two:

• Topical antibiotics (e.g., mupirocin ointment). In cases where a patient has a few isolated, superficial lesions with no other symptoms, physicians may prescribe a topical antibiotic ointment to be applied to the affected areas three to four times daily to help clear up the lesions.

  Topical antibiotics should be applied after washing the area with a mild soap or cleanser and patting it dry. Regular use of antibacterial soap is not recommended because it may create antibiotic-resistant bacteria.

• Oral antibiotics (e.g., erythromycin, dicloxacillin). Physicians usually prescribe oral antibiotics only for severe cases of nonbullous impetigo and cases of ecthyma. The entire course of prescribed antibiotics should be taken, even if symptoms improve, to prevent recurrence or resistance of the bacteria to antibiotic treatment. Antibiotic treatment usually results in rapid clearing of all lesions.

Patients may also benefit from soaking the affected area in warm water for 15 to 20 minutes. This will help remove the scabs. A physician should be contacted if the skin does not improve within three days of starting treatment. The development of fever and/or warmth or tenderness around the rash is also cause for concern.Prevention methods for impetigo
The best way to prevent many skin infections is to keep the skin clean. Any cuts, scrapes, insect bites, burns or other wounds should be cleaned and treated promptly to prevent infection. People can also prevent impetigo by avoiding contact with infected patients.

People with impetigo can prevent spreading the sores to other parts of their body, as well as avoid transmitting it to others by:

• Staying home until the infection is no longer contagious. A child with impetigo should be kept out of school or other activities, usually until 24 hours after treatment has begun.
• Gently cleaning the affected areas with a mild soap or cleanser and then covering the areas lightly with gauze or another type of nonstick dressing.
• Washing clothing, bedding and towels daily if infected.  These items should not be shared with others.  
• Wearing gloves when applying antibiotic ointments and washing hands thoroughly afterward.
• Refraining from scratching or touching the lesions until they heal. If necessary, cut children's nails to prevent them from scratching the lesions.
• Not preparing or handling food until given approval from their physician.

Questions for your doctor regarding impetigo
Preparing questions in advance can help parents to have more meaningful discussions with their child’s physicians. Parents may wish to ask their child’s doctor the following questions regarding impetigo:

1. Do my child’s symptoms indicate impetigo?

2. How serious is my child’s case of impetigo?

3. What form of impetigo does my child have?

4. Is impetigo dangerous to my child’s overall health? What complications may develop?

5. Can my child’s condition spread to other parts of the body or other people? If so, how long will my child be contagious?

6. How can I prevent the condition from spreading to other members of my family?

7. How long will my child have to be out of school?

8. What are my child’s treatment options and how effective are they?

9. When can I expect my child’s symptoms to subside?

10. Will my child have scarring after the condition subsides?

11. If my children are treated for impetigo can they get it again? If so, how can I prevent this?