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FACT SHEET: Impetigo (also known as “school sores”; includes “impetigo contagiosa” [“non-bullous impetigo”], “bullous impetigo”, and “ecthyma”; usually caused by staphylococcal [staph] bacteria — typically S. aureus — but also sometimes by streptococcal [strep] bacteria — typically S. pyogenes, also known as Group A Streptococcus [GAS])

Date of Publication: March 11, 2013
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Is the initiation of non-invasive dental hygiene procedures* contra-indicated?

  • No.

Is medical consult advised? 

  • Yes. While a medical consult for oral health reasons is not required, a referral to a primary care provider (e.g., physician or nurse practitioner) is appropriate for definitive diagnosis and treatment.

Is the initiation of invasive dental hygiene procedures contra-indicated?**

  • No.

Is medical consult advised? 

  • Yes; see above.

Is medical clearance required? 

  • No.

Is antibiotic prophylaxis required? 

  • No.

Is postponing treatment advised?

  • Possibly. If facial lesions are widespread, perioral lesions exist, or there is pain with mouth opening, most dental hygiene procedures should be postponed until patient/client’s impetigo has been treated. Patients/clients are usually no longer contagious 24 (but up to 48) hours after beginning antibiotic treatment, and impetigo lesions typically resolve in 7 to 10 days with treatment. Untreated, impetigo usually heals in 2 to 3 weeks.

Oral management implications

  • Mode of transmission is often autoinfection, exacerbated by scratching. Staph and strep often live harmlessly on the skin. Impetigo can also be spread by direct contact with a person who has a purulent lesion or is an asymptomatic (usually nasal) carrier of a pathogenic strain. In addition, spread may occur via touching items that have come in contact with impetigo lesions. Children are commonly infected through a break in the skin via a cut, scrape or insect bite, but they can also develop impetigo without having visible skin damage. In adults, impetigo is usually the result of an injury to the skin, such as dermatitis. Scabies, chickenpox, immunosuppression, burns, warm/humid climate, poor hygiene, and crowded environments are other risk factors. Impetigo spreads easily in schools and daycare settings.  
  • The face, especially the perioral region, is frequently involved.
  • The lesions appear 1 to 10 days after the patient/client has been infected (i.e., incubation period).
  • Ensure appropriate infection control measures are in place (e.g., gloves and hand washing) to prevent bacterial spread from the patient/client’s face to the dental hygienist or the operatory. Ideally, facial lesions will have been treated, at least to the point of being non-contagious, prior to dental procedures.
  • Persons with impetigo should cover their lesions to prevent spreading the infection to others and to other body parts.

Oral manifestations

  • None internal in the mouth. However, in children (especially those aged 2 to 6 years), perioral lesions are common, as described below.

Related signs and symptoms

  • Impetigo is a skin infection most commonly seen in young children (2−6 years). While lesions can appear anywhere, they usually appear on the face, arms, or legs. The condition is usually self-limiting, but antibiotic treatment1 accelerates resolution.
  • Lesions present in different ways, including the following:
    • red or pimple-like sores that rupture and ooze and then form golden, honey-coloured crusts (“impetigo contagiosa”, the most common type of impetigo), which typically occurs around the mouth and nose)
    • painless, fluid-filled blisters (“bullous impetigo”), which usually occurs on the trunk, arms, and legs of infants and children younger than 2 years
    • painful fluid- or pus-filled sores that result in deep ulcers (“ecthyma”)
    • itchiness.
  • Lymphadenopathy (swollen lymph nodes) and/or fever may occur.
  • While impetigo usually isn’t dangerous, it sometimes leads to cellulitis and, more rarely, serious complications such as kidney damage from acute post-streptococcal glomerulonephritis (ASPGN). Other complications include: lymphangitis (inflammation of lymph vessels); bacteremia; staphylococcal scalded skin syndrome; streptococcal toxic shock syndrome;  scarlet fever; post-inflammatory pigmentation; and scarring (especially with ecthyma).

References and sources of more detailed information


Date: December 10, 2012
Revised: February 22, 2020; January 23, 2026


FOOTNOTES

1 Treatment is antibiotics that target both group A strep and S. aureus. Topical antibiotics are used for less severe/localized cases, and oral antibiotics are used for multiple lesions, significant soft tissue infections, or during community outbreaks.


* Includes oral hygiene instruction, fitting a mouth guard, taking an impression, etc.
** Ontario Regulation 501/07 made under the Dental Hygiene Act, 1991. Invasive dental hygiene procedures are scaling teeth and root planing, including curetting surrounding tissue.