Sections View Full Chapter Figures Tables Videos Annotate Full Chapter Figures Tables Videos Supplementary Content + Download Section PDF Listen ++ For further information, see CMDT Part 6-25: Impetigo + Key Features Download Section PDF Listen +++ +++ 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 Download Section PDF Listen +++ +++ 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 + Diagnosis Download Section PDF Listen +++ ++ Gram stain and culture confirm the diagnosis + Treatment Download Section PDF Listen +++ ++ 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 5 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 + Outcome Download Section PDF Listen +++ +++ Prevention ++ Individuals should not share towels if there is a case of impetigo in the household + Reference Download Section PDF Listen +++ + +Hartman-Adams H et al. Impetigo: diagnosis and treatment. Am Fam Physician. 2014 Aug 15;90(4):229–35. [PubMed: 25250996]