Impetigo is the most common bacterial skin infection in children worldwide, with a global prevalence of over 162 million.[2]Bowen AC, Mahé A, Hay RJ, et al. The global epidemiology of impetigo: a systematic review of the population prevalence of impetigo and pyoderma. PLoS One. 2015 Aug 28;10(8):e0136789.
https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0136789
http://www.ncbi.nlm.nih.gov/pubmed/26317533?tool=bestpractice.com
[3]Barbieri E, Porcu G, Dona' D, et al. Non-bullous impetigo: incidence, prevalence, and treatment in the pediatric primary care setting in Italy. Front Pediatr. 2022;10:753694.
https://www.doi.org/10.3389/fped.2022.753694
http://www.ncbi.nlm.nih.gov/pubmed/35433549?tool=bestpractice.com
Median childhood prevalence is 12.3%.[2]Bowen AC, Mahé A, Hay RJ, et al. The global epidemiology of impetigo: a systematic review of the population prevalence of impetigo and pyoderma. PLoS One. 2015 Aug 28;10(8):e0136789.
https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0136789
http://www.ncbi.nlm.nih.gov/pubmed/26317533?tool=bestpractice.com
Around 10% of children presenting to US medical clinics with skin complaints are diagnosed with impetigo.[4]Prindaville B, Simon SD, Horii KA. Dermatology-related outpatient visits by children: implications for workforce and pediatric education. J Am Acad Dermatol. 2016 Jul;75(1):228-9.
https://www.doi.org/10.1016/j.jaad.2016.02.1219
http://www.ncbi.nlm.nih.gov/pubmed/27317526?tool=bestpractice.com
[5]Dollani LC, Marathe KS. Impetigo/Staphylococcal scalded skin disease. Pediatr Rev. 2020 Apr;41(4):210-12.
https://www.doi.org/10.1542/pir.2018-0206
http://www.ncbi.nlm.nih.gov/pubmed/32238552?tool=bestpractice.com
Impetigo is diagnosed most frequently in black children.[6]Ho T, Taylor MT, Marathe KS, et al. Most common pediatric skin conditions managed in outpatient dermatology clinics in the United States stratified by race and ethnicity. Pediatr Dermatol. 2021 Nov;38 Suppl 2:129-31.
https://www.doi.org/10.1111/pde.14693
http://www.ncbi.nlm.nih.gov/pubmed/34339074?tool=bestpractice.com
The annual incidence of impetigo in the UK is approximately 80/100,000 in children aged 0 to 4 years, decreasing to approximately 50/100,000 in those aged 5 to 14 years. It decreases further in older age groups.[7]Elliot AJ, Cross KW, Smith GE, et al. The association between impetigo, insect bites and air temperature: a retrospective 5-year study (1999-2003) using morbidity data collected from a sentinel general practice network database. Fam Pract. 2006 Oct;23(5):490-6.
https://academic.oup.com/fampra/article/23/5/490/571710
http://www.ncbi.nlm.nih.gov/pubmed/16873392?tool=bestpractice.com
Bullous impetigo can occur at any age. Nonbullous impetigo also occurs in all age groups, but is a particular concern in newborns, in whom it is potentially more serious due to increased risk of sepsis and other life-threatening infections (e.g., pneumonia).[8]De Rose DU, Pugnaloni F, Martini L, et al. Staphylococcal infections and neonatal skin: data from literature and suggestions for the clinical management from four challenging patients. Antibiotics (Basel). 2023 Mar 23;12(4).
https://www.doi.org/10.3390/antibiotics12040632
http://www.ncbi.nlm.nih.gov/pubmed/37106994?tool=bestpractice.com
In the US and Europe, Staphylococcus aureus is the usual causative agent.
PCDS Clinical Guidance: impetigo
Opens in new window In hot and humid areas of the world, the streptococcal form predominates and is often endemic.[9]Kakar N, Kumar V, Mehta G, et al. Clinico-bacteriological study of pyodermas in children. J Dermatol. 1999 May;26(5):288-93.
http://www.ncbi.nlm.nih.gov/pubmed/10380429?tool=bestpractice.com
[10]Tewodros W, Muhe L, Daniel E, et al. A one-year study of streptococcal infections and their complications among Ethiopian children. Epidemiol Infect. 1992 Oct;109(2):211-25.
http://www.ncbi.nlm.nih.gov/pubmed/1397112?tool=bestpractice.com
The incidence of impetigo is higher in summer months, due to environmental factors such as increased humidity.[9]Kakar N, Kumar V, Mehta G, et al. Clinico-bacteriological study of pyodermas in children. J Dermatol. 1999 May;26(5):288-93.
http://www.ncbi.nlm.nih.gov/pubmed/10380429?tool=bestpractice.com
[11]Loffeld A, Davies P, Lewis A, et al. Seasonal occurrence of impetigo: a retrospective 8-year review (1996-2003). Clin Exp Dermatol. 2005 Sep;30(5):512-4.
http://www.ncbi.nlm.nih.gov/pubmed/16045681?tool=bestpractice.com
Impetigo is typically found in conditions of overcrowding, poor hygiene, malnutrition, and where the skin barrier is defective (e.g., due to insect bites and scabies).[1]Hartman-Adams H, Banvard C, Juckett G. Impetigo: diagnosis and treatment. Am Fam Physician. 2014 Aug 15;90(4):229-35.
https://www.aafp.org/afp/2014/0815/p229.html
http://www.ncbi.nlm.nih.gov/pubmed/25250996?tool=bestpractice.com
[7]Elliot AJ, Cross KW, Smith GE, et al. The association between impetigo, insect bites and air temperature: a retrospective 5-year study (1999-2003) using morbidity data collected from a sentinel general practice network database. Fam Pract. 2006 Oct;23(5):490-6.
https://academic.oup.com/fampra/article/23/5/490/571710
http://www.ncbi.nlm.nih.gov/pubmed/16873392?tool=bestpractice.com
[9]Kakar N, Kumar V, Mehta G, et al. Clinico-bacteriological study of pyodermas in children. J Dermatol. 1999 May;26(5):288-93.
http://www.ncbi.nlm.nih.gov/pubmed/10380429?tool=bestpractice.com
[12]Kristensen JK. Scabies and pyoderma in Lilongwe, Malawi. Prevalence and seasonal fluctuation. Int J Dermatol. 1991 Oct;30(10):699-702.
http://www.ncbi.nlm.nih.gov/pubmed/1955222?tool=bestpractice.com
[13]Centers for Disease Control and Prevention. Group A Streptococcal (GAS) disease: impetigo. Jun 2022 [internet publication].
https://www.cdc.gov/groupastrep/diseases-hcp/impetigo.html
It is highly infectious through fomites.
The nasal carriage of Staphylococcus aureus can be as high as approximately 40% for bullous impetigo, and approximately 60% for the nonbullous form.[9]Kakar N, Kumar V, Mehta G, et al. Clinico-bacteriological study of pyodermas in children. J Dermatol. 1999 May;26(5):288-93.
http://www.ncbi.nlm.nih.gov/pubmed/10380429?tool=bestpractice.com
[14]Durupt F, Mayor L, Bes M, et al. Prevalence of Staphylococcus aureus toxins and nasal carriage in furuncles and impetigo. Br J Dermatol. 2007 Dec;157(6):1161-7.
http://www.ncbi.nlm.nih.gov/pubmed/17916211?tool=bestpractice.com
MRSA can be a causative organism and is seen more often in cases of nonbullous impetigo.[15]Shi D, Higuchi W, Takano T, et al. Bullous impetigo in children infected with methicillin-resistant Staphylococcus aureus alone or in combination with methicillin-susceptible S. aureus: analysis of genetic characteristics, including assessment of exfoliative toxin gene carriage. J Clin Microbiol. 2011 May;49(5):1972-4.
http://www.ncbi.nlm.nih.gov/pubmed/21430094?tool=bestpractice.com