Guideline sources The following summarized guidelines for the evaluation and management of ecthyma and impetigo are prepared by our editorial team based on guidelines from the Surgical Infection Society Europe (SIS-E/WSES 2018), the Infectious Diseases Society of America (IDSA 2014), and the American Association of Family Physicians (AAFP 2007). 1 1 1 2 2 2 2 3 3 3 4 5 Definition Impetigo is a highly contagious bacterial infection of the superficial layers of the epidermis. Ecthyma is a deeply ulcerated form of impetigo that extends into the dermis. 2 4 Epidemiology Impetigo is nearly always caused by S. aureus and/or -hemolytic Streptococcus species. Community-acquired MRSA is an increasingly frequent etiological agent. 2 Pathophysiology Impetigo predominantly affects children. In patients under 18 years of age, the incidence of impetigo is estimated at 206 per 100,000 person-years. 2 5 Disease course Impetigo begins as erythematous papules that rapidly evolve into vesicles and pustules that rupture, with the dried discharge forming honey-colored crusts on an erythematous base. Ecthyma begin as vesicles that rupture, resulting in circular, erythematous ulcers with adherent crusts, often with surrounding erythematous edema. 1 https://web.pathway.md/diseases/rec49NrZTizWsnZ2l 1/4 6/29/23, 4:15 AM Ecthyma and impetigo Pathway Prognosis and risk of recurrence Acute poststreptococcal glomerulonephritis is a serious complication that affects between 1 and 5 percent of patients with nonbullous impetigo. Rheumatic fever does not appear to be a potential complication of impetigo. Impetigo usually resolves without scarring within two weeks if left untreated. Unlike impetigo, ecthyma heals with scarring. 1 3 3 Guidelines 1. Diagnostic investigations Gram stain and culture: Obtain Gram stain and culture of the pus or exudates from skin lesions in patients with impetigo and ecthyma, in order to help identify whether S. aureus and/or a -hemolytic Streptococcus is the cause. B Consider empiric treatment without obtaining Gram stain and culture in patients with a typical clinical presentation. B 2. Medical management Route of antibiotic administration: As per IDSA 2014 guidelines, use either oral or topical antibiotics for the treatment of most patients with bullous and nonbullous impetigo. Show 2 more As per AAFP 2007 guidelines: Use topical antibiotics for the treatment of patients with impetigo in whom there is a limited involvement of BSA. A Consider using an oral antibiotic for the treatment of patients with impetigo in whom there is extensive disease, and in patients with associated systemic symptoms. C Oral antibiotic therapy: As per WSES 2018 guidelines: Use an antibiotic that is active against Gram-positive bacteria for the treatment of impetigo. B Use an antibiotic that is active against community-acquired MRSA for the treatment of impetigo in patients at risk for MRSA, and in patients who do not respond to first-line therapy. B As per IDSA 2014 guidelines, use an antibiotic active against S. aureus for the systemic treatment of ecthyma or impetigo, and complete 7 days of treatment. A Show 3 more As per AAFP 2007 guidelines: Use one of the following agents as first-line antibiotics for the treatment of impetigo: an antistaphylococcal penicillin, such as dicloxacillin 250-500 mg PO QID for 10 days https://web.pathway.md/diseases/rec49NrZTizWsnZ2l 2/4 6/29/23, 4:15 AM Ecthyma and impetigo Pathway a cephalosporin, such as cephalexin 250-500 mg PO QID for 10 days amoxicillin/clavulanic acid 250-500 mg PO BID for 10 days. A Avoid using oral penicillin V or amoxicillin for the empiric treatment of impetigo. D Topical antibiotic therapy: As per IDSA 2014 guidelines, use one of the following agents as first-line topical agents for the treatment of bullous and nonbullous impetigo in patients in whom oral antibiotics are not indicated: mupirocin ointment to lesions BID for 5 days retapamulin ointment to lesions BID for 5 days. A As per AAFP 2007 guidelines, use muciprocin or fusidic acid as first-line topical agents for the treatment of impetigo in patients in whom oral antibiotics are not indicated. A Show 2 more 3. Specific circumstances Outbreaks of poststreptococcal glomerulonephritis: administer systemic antibiotics to patients with ecthyma during outbreaks of poststreptococcal glomerulonephritis, to help eliminate nephritogenic strains of Streptococcus pyogenes from the community. B Clinical findings Symptoms Past medical history Infection Bacterial infection Pain Inflammation Skin infection Moist environment Head and neck exam Angular cheilitis References 1. Stevens DL, Bisno AL, Chambers HF et al. Practice guidelines for the diagnosis and management of skin and soft tissue infections: 2014 update by the Infectious Diseases Society of America. Clin Infect Dis. 2014 Jul 15;59 2):e10 52. Open 2. Sartelli M, Guirao X, Hardcastle TC et al. 2018 WSES/SIS E consensus conference: recommendations for the management of skin and soft-tissue infections. World J Emerg Surg. 2018 Dec 14;13 58. Open 3. Cole C, Gazewood J. Diagnosis and treatment of impetigo. Am Fam Physician. 2007 Mar 15;75 6 859 64. Open 4. Yee Gyung Kwak, Seong Ho Choi, Tark Kim et al. Clinical Guidelines for the Antibiotic Treatment for Community-Acquired Skin and Soft Tissue Infection. Infect Chemother. 2017 Dec;49 4 301 325. Open https://web.pathway.md/diseases/rec49NrZTizWsnZ2l 3/4 6/29/23, 4:15 AM Ecthyma and impetigo Pathway 5. S Koning, R S A Mohammedamin, J C van der Wouden et al. Impetigo: incidence and treatment in Dutch general practice in 1987 and 2001 results from two national surveys. Br J Dermatol. 2006 Feb;154 2 239 43. Open https://web.pathway.md/diseases/rec49NrZTizWsnZ2l 4/4