Impetigo
Impetigo is a superficial bacterial skin infection primarily affecting children and characterized by inflammation, blisters, itchiness, and scabbing. It often occurs when bacteria such as group A streptococcus or Staphylococcus aureus enter the skin through minor breaks, like insect bites. Infection typically manifests as vesicopustules that rupture, forming a distinct golden-yellow crust. Impetigo is highly contagious, frequently spreading in crowded environments such as schools or military settings, and is more common during hot, humid summer months.
Treatment generally involves topical or oral antibiotics, with options including beta-lactamase-resistant penicillins or first-generation cephalosporins, particularly as resistance to penicillin has increased. Topical antibiotics like mupirocin are effective for mild cases, while oral antibiotics may be necessary for more severe infections. Good personal hygiene, including frequent hand washing and avoiding the sharing of personal items, is crucial in preventing the spread of impetigo. While the condition is usually self-limiting and lesions heal without scarring, appropriate treatment is essential to manage symptoms and reduce contagion.
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Subject Terms
Impetigo
ANATOMY OR SYSTEM AFFECTED: Immune system, skin
DEFINITION: A superficial bacterial infection of the skin
CAUSES: Bacterial infection
SYMPTOMS: Skin inflammation, blisters, itchiness, scabbing
DURATION: Acute
TREATMENTS: Injection or oral administration of antibiotics (penicillin, erythromycin)
Causes and Symptoms
Impetigo is a superficial bacterial skin infection usually caused by group A streptococcus, Staphylococcus aureus, or a mixture of both. Group A streptococcus was originally the predominant pathogen, but S. aureus has since become the most common strain. Impetigo caused by either of these is clinically identical.
Children are most commonly affected by impetigo, and infection is often preceded by minor such as insect bites. Outbreaks predominantly occur during the summer months when the climate is hot and humid. Impetigo is very contagious and easily spread in crowded conditions such as in families, schools, the military, and athletics. Poverty and poor personal can also predispose individuals to infection.
A typical infection first develops as multiple vesicopustules, which rupture and form a characteristic golden yellow crust. The lesions are painless but commonly pruritic (itchy), and scratching can serve to spread infection. Systemic symptoms are rare, but there can be local lymphadenopathy. The face, particularly the region around the mouth, is a common site of infection.
Treatment and Therapy
Topical and oral antibiotics have been used for the treatment of impetigo. Historically, the treatment of choice was penicillin or ampicillin. This has changed, however, as the most predominant bacteria are now S. aureus instead of group A streptococcus, which almost universally produces a beta-lactamase that makes them resistant to penicillin. It is now recommended to use a beta-lactamase-resistant penicillin such as dicloxacillin or a first-generation cephalosporin such as cephalexin. Erythromycin can be used if the patient is allergic to penicillin.
Topical antibiotics such as mupirocin and fusidic acid (the latter not available in the United States) are very effective treatments. Mupirocin has been shown to be as effective as erythromycin. The US Food and Drug Administration approved ozenoxacin for topical treatment of impetigo in 2017. Topical antibiotics are used with mild or moderate cases; and oral antibiotics are reserved for more advanced cases. Topical antibiotics are as effective and have fewer side effects, which make them a better choice in less severe cases. A ten-day course is recommended whether oral or topical antibiotics are used.
Gentle cleansing of the area with soap and water can be helpful. Personal hygiene may be discussed with the patient to help prevent of infection. Frequent hand washing and not sharing bath linens can help prevent spread of the bacteria. The lesions usually heal without scarring.
Bibliography
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