Using towels and soap in steam baths could reduce infection

The article by Landen et al describes an association between furunculosis and the use of steam baths in an Alaskan village. Their investigation identified a comparatively unusual source of an outbreak of dermatitis—Staphylococcus aureus in “recreational” water—and the challenge of implementing simple preventive measures that would change a cultural practice. The boils occurred primarily on the buttocks and the backs of the upper thighs and were not preceded by apparent skin trauma. However, the furuncles were likely to have been preceded by folliculitis, and the authors present a convincing case that transmission occurred primarily through sitting in the steam baths. In this outbreak S aureus entered through intact skin in contrast with other outbreaks in which trauma to the skin was a predisposing factor for skin infections (primarily boils) among those going rafting, members of football teams, and meat packers.^1,2,3,4 The use of steam baths could result in trauma that was not apparent (for example, from sliding on wooden seats).

The combination of sitting on communal seats for long periods of time (facilitating person to fomite to person transmission) in heat at “incubator temperatures” (enabling the organism to persist and grow) and sweating (leading to opening of skin pores and entry of the organism), probably contributed to transmission and infection. In contrast, communal toilet seats have not been associated with outbreaks of disease. Outbreaks of Pseudomonas aeruginosa dermatitis have been associated with hot tubs, and outbreaks of dermatitis caused by Schistosoma species have been associated with lakes.⁵ While the authors emphasize the transmission of organisms from one person to another while steam bathing, bathers in this setting are also at risk of infection by their own flora.

The findings of this paper add to earlier reports of outbreaks of furunculosis in Alaskan villages by looking for causes and suggesting a practical preventive measure. The authors found that sitting on a towel in the steam bath was protective: 39% (data not shown) of people with furunculosis used a towel compared with 68% (data not shown) of the controls in a multivariate model of residents who reported using a steam bath. Assuming that the 120 people included in the multivariate model are representative of those who use the steam baths, 70% of the cases of furunculosis among people who did not sit on a towel (42% of all cases) could have been prevented by the use of a towel (the preventable fraction is 1 - the odds ratio).⁶ This practice should be promoted. The effectiveness of other possible preventive measures, such as showering before using the steam baths, could not be assessed either because too few people used them or because the measures were too difficult logistically to be implemented.

Future outbreaks could probably be prevented or limited if those residents using the steam baths consistently used their own towels and followed their steam bath by soaping up even when there was no evidence of an outbreak. Ultimately, the community will need to decide whether maintaining the current practice of using steam baths without protective measures is worth the risk of future outbreaks. There is potential for controversy if the use of towels is made compulsory: there is the tension between the inconvenience of a preventive measure, which brings about the loss of a personal freedom (that is, the choice of whether to sit on a towel in a steam bath), and the morbidity that could result from not adhering to a preventive measure (the risk of repeated outbreaks of furunculosis in the community).