Free Residual Chlorine in Bathing Water Reduces the Water‐Holding Capacity of the Stratum Corneum in Atopic Skin

Abstract

Some patients with atopic dermatitis (AD) develop dry skin or exacerbated cutaneous inflammations with frequent swimming in public pools or after bathing. We examined the effects of residual chlorine in bathing water on the function of the stratum corneum (SC) in patients with AD and determined the lowest chlorine concentration showing an effect. In addition, we investigated the relationship between the free residual chlorine concentration in bathing water and the water-holding capacity of the SC in patients with AD. Twenty patients with AD and 10 normal control (NC) subjects were included in this study. The hydration status of the SC on the flexor surface of the forearm was measured with a corneometer before and after the subject's arms were immersed in tubs filled with comfortably hot water (40 degrees C) containing residual chlorine at concentrations of 0, 0.5, 1.0 and 2.0 mg/L for 10 minutes in a room maintained at normal temperature (24 degrees C) and relative humidity (55%). The water-holding capacity of the SC after immersion was calculated by integration of the hydration status determined every 30 seconds over a period of 10 minutes. In the patients with AD, the average SC hydration status after immersion in comfortably hot water containing residual chlorine at 1.0 and 2.0 mg/L was significantly lower than that following immersion in water containing a negligible concentration of residual chlorine (i.e., less than 0.03 mg/L) (p<0.05). In the NC subjects, significant differences were observed only between the 2.0 mg/L and the negligible residual chlorine groups (p<0.05). The water-holding capacity of the SC was significantly decreased with a residual chlorine concentration of 0.5 mg/L or higher in the patients with AD (p<0.01). However, in the NC subjects, a significant decrease in water-holding capacity was observed only at a residual chlorine concentration of 2 mg/L (p<0.01). These results indicate, first, that the water-holding capacity of the SC in patients with AD is more sensitive to free residual chlorine exposure than that in NC subjects without AD. Second, these results suggest that free residual chlorine exposure in patients with AD may play a role in the development or exacerbation of AD.

Swimming pool attendance and risk of asthma and allergic symptoms in children

“…Eczema (or atopic dermatitis) is a chronic inflammatory skin disease characterised by the formation of specific antibodies (IgE) to environmental allergens, which frequently starts early in infancy and affects 15-30% of children in industrialised countries [25]. Although IgE blood levels were unrelated to both cumulative and acute pool exposure in two studies [26,27], a semi-experimental study suggested that dermal pool exposure may play a role in the exacerbation of atopic dermatitis [28]. Furthermore, it has been described that workers engaged in wet-works are at risk for suffering irritant dermatitis [29], which in turn may enhance the atopic dermatitis [30].…”

Chlorine, Chlorination By-Products and Their Allergic and Respiratory Health Effects

“…Furthermore, Seki et al [21] conducted tests under conditions not exactly similar to pool water. Therefore, results might be different regarding pool attendance.…”

“…Seki et al [21] investigated potential effects of chlorine in bathing water on atopic and non-atopic skin In order to show this, they bathed the forearm of the participants in chlorinated water. The water-holding capacity of the stratum corneum of patients with atopic dermatitis proved to be more sensitive to free residual chlorine exposure, than that of normal control subjects.…”

Zu den Gefahren des Wassers

“…In einem meiner alten exzellenzbasierten Lehrbücher hatte ich noch gefunden, dass Chlorwasser bei einem recht guten Hautzustand des Neurodermitikers sogar "abhärtend" wirken könne und durchaus zu empfehlen sei. Dennoch, das freie Chlor im Schwimmbadwasser reduziert die wasserbindende Kapazität des Stratum Corneum, wie bei atopischer Haut bereits von einer japanischen Arbeitsgruppe gezeigt wurde [2].…”