Skip to Main Content

We have a new app!

Take the Access library with you wherever you go—easy access to books, videos, images, podcasts, personalized features, and more.

Download the Access App here: iOS and Android. Learn more here!

For further information, see CMDT Part 6-25: Impetigo

Key Features

Essentials of Diagnosis

  • Superficial blisters filled with purulent material that rupture easily

  • Crusted superficial erosions

  • Positive Gram stain and bacterial culture

General Considerations

  • A contagious and autoinoculable infection of the skin caused by staphylococci or rarely streptococci

  • In temperate climates, most cases are associated with Staphylococcus aureus infection

  • Streptococcus species are more common in tropical climates

Clinical Findings

Symptoms and Signs

  • The lesions consist of macules, vesicles, bullae, pustules, and honey-colored gummy crusts that when removed leave denuded red areas

  • The face and other exposed parts are most often affected

  • Ecthyma is a deeper form of impetigo caused by staphylococci or streptococci, with ulceration and scarring; it occurs frequently on the extremities

Differential Diagnosis

  • Contact dermatitis (acute)

  • Herpex simplex


  • Gram stain and culture confirm the diagnosis


  • Soaks and scrubbing can be beneficial, especially in unroofing lakes of pus under thick crusts

  • Topical agents such as bacitracin 500 units/g applied twice daily, mupirocin 2% ointment applied three times daily, or retapamulin 1% ointment applied twice daily can be attempted for 5–14 days for infections limited to small areas

  • Cephalexin, 250 mg four times daily orally

  • Doxycycline, 100 mg twice daily orally, or trimethoprim-sulfamethoxazole, double-strength twice daily orally, can be used for penicillin allergy and methicillin-resistant S aureus

  • Recurrent impetigo, which is due to nasal carriage of S aureus, is treated with rifampin, 300 mg orally twice daily, or mupirocin intranasal ointment applied intranasally twice daily for 14 days

  • Bleach baths (1/4 to 1/2 cup per 20 L of bathwater for 15 minutes 3–5 times weekly) for all family members may help reduce the spread



  • Individuals should not share towels if there is a case of impetigo in the household


Galli  L  et al; Italian Pediatric Infectious Diseases Society; Italian Pediatric Dermatology Society. Common community-acquired bacterial skin and soft-tissue infections in children: an intersociety consensus on impetigo, abscess, and cellulitis treatment. Clin Ther. 2019;41:532.
[PubMed: 30777258]  
Huang  SS  et al; Project CLEAR Trial. Decolonization to reduce postdischarge infection risk among MRSA carriers. N Engl J Med. 2019;380:638.
[PubMed: 30763195]  

Pop-up div Successfully Displayed

This div only appears when the trigger link is hovered over. Otherwise it is hidden from view.