Background: The association between physical and chemical parameters in swimming pool water and the incidence of contact dermatitis (CD) in hydrotherapists was studied.
Methods: Chemical and physical parameters characterizing the water and air environment of swimming pools conducting hydrotherapy program were recorded. Differences between the values of these parameters associated with affected and non-affected hydrotherapists employed in 39 pools were tested statistically.
Results: No significant difference was found between the means of each of the physical and chemical parameters associated with the affected and the non-affected group of hydrotherapists. The prevalence ratio of the incidence of CD in pools chlorinated by gaseous chlorine was significantly higher than that in pools disinfected by other forms of chlorine compounds (PR = 1.49, CI = 1.17-1.89, P = 0.017).
Conclusions: Dosing the water with larger amounts of gaseous chlorine compared to other disinfectants and a subsequent temporary decrease in the pH of the water may produce a more aggressive environment. It is suggested that combined effect of the various factors concomitantly with the irritating effect of prolonged exposure to water may trigger CD in pools treated with other chlorine-based compounds.