Non-bullous impetigo is a superficial skin infection commonly seen in children and teenagers. It is caused by Staphylococcus aureus or Group A streptococcus (Streptococcus pyogenes). Constitutional symptoms and fever are minimal. Minor trauma, such as insect bites or abrasions, can predispose to infection. Additional predisposing factors include a warm humid climate, atopic dermatitis, and participation in contact sports.
Although methicillin-resistant S. aureus (MRSA) infection of the skin usually presents as recurrent furunculosis or skin abscesses, MRSA has been shown to cause impetigo. Culture and sensitivities should always be performed in patients with lesions suspicious for cutaneous infection, and empiric coverage for MRSA should be instituted if clinical suspicion is high.
ICD10CM: L01.01 – Non-bullous impetigo
SNOMEDCT: 238374001 – Non-bullous impetigo
Differential Diagnosis & Pitfalls
A diagnosis of non-bullous impetigo is often mistakenly disregarded due to the lack of inflammation or induration.
Impetigo is a common and contagious bacterial skin infection that is usually a minor problem, but sometimes complications may occur that require treatment. Complications related to impetigo can include deeper skin infection (cellulitis), infections of the brain, and kidney inflammation. Impetigo often starts with a cut or break in the skin that allows bacteria to enter. Impetigo is usually caused by "staph" (Staphylococcus) or "strep" (Streptococcus) bacteria. Impetigo can be further classified into 2 types: bullous and nonbullous.
Nonbullous impetigo accounts for 70% of all cases and appears as tiny fluid-filled blisters that develop into honey-colored, crusty lesions. Generally they do not cause any pain or redness to the surrounding skin.
Bullous impetigo appears as larger clear blisters filled with fluid. When these blisters break, they may leave a scale behind. Bullous impetigo is primarily seen in infants and children. It is less common in teenagers and young adults.
Who’s At Risk
Impetigo is very common in children and infants, affecting up to 10% of children who come to a pediatric clinic. Children up to 6 years old are most likely to be infected. Impetigo also may occur in adults. Those who live in a warm, humid climate are more often affected. Insect bites, crowded living conditions, and poor skin cleansing increase the risk of infection. It may spread easily through schools, daycare centers, and nurseries. Participation in sports requiring skin-to-skin contact, having a weak immune system, or having a chronic skin problem such as eczema can also increase the risk of getting impetigo. Lesions on the neck and scalp may occur with head lice (pediculosis capitis).
Signs & Symptoms
Tiny pimples or red areas quickly turn into oozing honey-colored crusted patches (usually less than an inch) that spread.
The face or traumatized areas of the skin are affected.
There may be some itching or swollen lymph nodes, but the person feels generally well (unless severe).
Sometimes deeper pus-filled sores and scabs that leave scars occur.
Mild – There are only a few areas over a small and local area of skin, and the person feels well otherwise.
Moderate – There are over 10 spots, and several small skin areas are affected.
Severe – There are many lesions, large areas of skin are affected, and/or the person feels ill with fever, diarrhea, or weakness.
Prevention is very important; keep the skin clean with soap and water. Treat cuts, scrapes, and insect bites by cleaning with soap and water and covering the area if possible.
For mild infection:
Gently wash the area with a mild soap and water twice or more daily, and cover with gauze or a non-stick dressing if possible.
An over-the-counter antibiotic ointment can be applied after washing the skin 3-4 times daily. Wash hands after application or wear gloves to apply.
To remove crusts, soak with a vinegar solution (1 tablespoon of white vinegar to a pint of water) for 15-20 minutes.
Wash clothing, towels, and bedding daily and don't share these with others.
Wash hands frequently, try not to touch the areas, and keep the fingernails trimmed.
Keep a child home until there are no scabs or open areas present.
When to Seek Medical Care
Seek care for any infection that is not improving. If the infection is moderate to severe or there is fever or pain, seek medical attention.
If currently being treated for a skin infection that has not improved after 2-3 days of antibiotics, return to the doctor.
Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) is a strain of "staph" bacteria resistant to antibiotics in the penicillin family, which have been the cornerstone of antibiotic therapy for staph and skin infections for decades. CA-MRSA previously infected only small segments of the population, such as health care workers and persons using injection drugs. However, CA-MRSA is now a common cause of skin infections in the general population. While CA-MRSA bacteria are resistant to penicillin and penicillin-related antibiotics, most staph infections with CA-MRSA can be easily treated by health care practitioners using local skin care and commonly available non-penicillin-family antibiotics. Rarely, CA-MRSA can cause serious skin and soft tissue (deeper) infections. Staph infections typically start as small red bumps or pus-filled bumps, which can rapidly turn into deep, painful sores. If you see a red bump or pus-filled bump on the skin that is worsening or showing any signs of infection (ie, the area becomes increasingly painful, red, or swollen), see your doctor right away. Many people believe incorrectly that these bumps are the result of a spider bite when they arrive at the doctor's office. Your doctor may need to test (culture) infected skin for MRSA before starting antibiotics. If you have a skin problem that resembles a CA-MRSA infection or a culture that is positive for MRSA, your doctor may need to provide local skin care and prescribe oral antibiotics. To prevent spread of infection to others, infected wounds, hands, and other exposed body areas should be kept clean and wounds should be covered during therapy.