Impetigo: the infection that runs through a kids’ group in a week
In Arizona in 2014, impetigo was the most frequent diagnosis in an outbreak of lesions among wrestlers. It is not a toddlers’ disease.
By Mat Maintenance Agency · Published September 5, 2026
Impetigo is a highly contagious bacterial skin infection, most often caused by group A strep or staph. It spreads through close contact with an infected person, which makes it a combat sports infection. Red sores that ooze then form a honey-coloured crust, mostly on the face, arms and legs. The member is kept off the mat until treated, the group informed, the mat disinfected.
What it is
A superficial bacterial skin infection. The CDC notes it is most common in children aged 2 to 5, but anyone can get it, and close contact with an infected person is the main risk factor. Contact sports tick the box: in the outbreak the CDC documented among Arizona high school wrestlers, impetigo accounted for nearly half of the diagnoses.
What it looks like
Red, itchy sores that break open and leak a clear fluid or pus for a few days, then cover with a honey-coloured crust. Mostly around the nose and mouth, on the arms and legs. It heals without scarring with treatment, but spreads fast until treated. The diagnosis is medical; do not guess it.
Why kids’ groups
Close contact, fragile skin, scrapes, fingernails, and the habit of touching sores then the mat. A kids’ jiu-jitsu or judo class is the most exposed group in a gym. Parents need to know what to look for: a sore that oozes or a yellow crust means a child who stays home and sees a doctor.
The 48 hours
The measures the CDC adopted in the Arizona outbreak fit in three lines: exclude visible uncovered lesions, disinfect the mats, provide hand sanitiser. In training, it is the same.
- Keep the child or member off the mat until medical advice and the start of treatment
- Inform the group’s parents the same day, with a simple description
- Disinfect the mat surface, padded walls and shared objects for the dwell time
- Wash towels, gis and rashguards in hot water
- Deep-reset the mat if a second case appears
Preventing it
Short fingernails for kids, shower after class, clean gi, cuts covered, and a discreet skin inspection by the coach at the start of class. Surface disinfection after every block and a deep clean at a fixed interval keep the mat’s bacterial load low.
What gym owners ask us
Can a treated child come back on the mat?
On medical clearance, generally after a period of treatment and when the sores no longer ooze. The doctor decides, not the coach.
Is it serious?
Rarely, with treatment. Without treatment the infection spreads and can get complicated. And a whole group can catch it.
Do we have to close the kids’ class?
Not in general. Isolate, inform, disinfect. A second case in the same week justifies a mat reset and a firm reminder of the rules.
An outbreak costs more than a cleaning.
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