Ringworm, herpes and impetigo: skin infections in grappling
The subject nobody enjoys bringing up, and the one that gets you turned away at a competition skin check. What has been measured, what is just custom, and what nobody has studied.
BJJ Square · Updated on 08/11/2026
Careful This page describes epidemiological data and rulebooks; it is not a guide to diagnosis or treatment. A skin lesion is assessed by a doctor: what you will find here is how widespread the problem is and how the return-to-mat rules work, not what to put on it.
In grappling the skin is a working surface: it is in contact with other people and with the mat for hours. Skin infections are a documented problem, and in jiu-jitsu they get discussed very little for one specific reason — almost all the research has been done on wrestlers, not on BJJ practitioners.
How common they are
A systematic review of 4,818 wrestlers reports a pooled prevalence of tinea gladiatorum — ringworm — of 34%, with enormous variability between studies (from 2.4% to 90%). The agent is almost exclusively a fungus called *Trichophyton tonsurans*: 92% of isolates.
In American college surveillance of wrestling, across 78,720 exposures, skin infections come out at 14.2 per 10,000. The surprise is which one is most frequent: not ringworm, but herpes — 41% of all recorded infections. Bacterial infections, impetigo included, account for 26%.
Note One figure that says a lot about organisation: 65% of the infections were concentrated in just five team-seasons. This is not a risk spread evenly: it depends enormously on how the gym is run.
Why herpes is more worrying than ringworm
- It is the most frequent in the available data.
- It does not go away: it stays in the body and can recur. The medical bodies covering combat sports write that opponents should know that catching it brings possible recurrences for life.
- It cannot be covered up: for treated ringworm the rulebooks allow the lesion to be covered, for active herpes they do not.
The mat matters less than people think
Blaming the mat would seem obvious, but the data tells it differently. Fungal contamination measured on mats is around 5% of samples, and above all the lesions appear on the trunk, face and scalp — not on the legs, which are the part in constant contact with the mat. The main route remains skin-to-skin contact.
Careful ⚠️ No study has ever quantified how much each of the two routes contributes. And no study has ever measured mat contamination in a BJJ gym: the data all comes from wrestling.
What actually works, measured
A study published in the *Journal of Athletic Training* measured bacterial load on mats during real matches, comparing products and procedures:
- Alcohol hand gel before every match: −78% bacterial load on the mat. It is the single most effective intervention measured.
- Disinfectants with residual action: −63% compared with those that act and stop, and up to −76% over a competition day.
- Mopping backwards, without walking back over the wet surface: bacteria carried in on shoes drop to a tenth.
- Footbaths did not work: the effect was cancelled out by the shared towel used straight afterwards.
Note The measure with the highest evidence grade in the National Athletic Trainers' Association recommendations is the most mundane one: do not share towels, gear, water bottles or razors. Daily mat cleaning, which is the recommendation repeated everywhere, is classed by the same association at the lowest evidence level — expert consensus, not data.
The rules for going back on the mat
In jiu-jitsu the IBJJF rulebook is surprisingly unprescriptive: after the weigh-in an inspector checks the skin, and anyone with lesions has to produce a medical statement certifying that they are not contagious. The final word rests with the event doctor. No minimum treatment period is specified.
In American scholastic wrestling, by contrast, the timings are written down: 72 hours of treatment for ringworm on the skin, two weeks for the scalp, ten days for a first herpes episode. These are criteria from another sport and another country, but they give a sense of the order of magnitude — and of how much jiu-jitsu leaves to the individual doctor.
Careful ⚠️ The medical body that explicitly covers jiu-jitsu as well states that its own recommendations are an extrapolation from those of other federations, that “empirical evidence for these recommendations is not available”, and that all the available studies were conducted on wrestlers. The rules exist; the data behind them, far less so.
The most useful thing you can do
If you have a skin lesion and you do not know what it is, the right move is not to cover it up and train: it is to get it looked at and stay off the mat until you know what it is. That holds for you, and it holds for the other twenty people you train with.
How to wash your gi and rash guard, and how often: how to wash your gi.
Frequently asked questions
- How common are skin infections in grappling?
- A systematic review of 4,818 wrestlers reports a pooled ringworm prevalence of 34%, with wide variability between studies. In American college surveillance, however, the most frequent infection turns out to be herpes, at 41% of recorded cases.
- Do you catch ringworm from the mat?
- The mat can act as a vector, but measured contamination is around 5% of samples, and the distribution of lesions — trunk, face, scalp — points to skin-to-skin contact as the main route. No study has quantified the relative weight of the two routes.
- What do you need to come back after a skin infection?
- Under the IBJJF rulebook you need a medical statement certifying that the lesion is not contagious, and the event doctor decides; no minimum treatment period is specified. Other sports, such as American scholastic wrestling, set precise timings instead.
- Which preventive measures actually work?
- Among those measured: alcohol hand gel before every match (-78% bacterial load on the mats), disinfectants with residual action, and mopping backwards. Not sharing towels and gear is the recommendation with the highest evidence grade.
- Are there studies on skin infections in BJJ?
- No. All the available research has been conducted on wrestlers and, to a lesser extent, judoka. There is no prevalence study on Brazilian Jiu-Jitsu practitioners.
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