As I was reading some studies at PubMed I came across this study on the effect of chlorine on the skin barrier function.
Skin barrier function is one measure of skin health. One of the thing the skin does is regulates what goes in and out of your body. For example it adjusts the water content of the skin in response to environmental humidity. It also keeps bacteria and other pathogens out of the body.
Compromised skin barrier function is a common feature in many skin conditions, acne included. As a result the skin becomes more vulnerable to breakouts.
So what this study found was that exposure to chlorine in bathing water decreased the water-holding capacity of the skin, i.e. more water escaped through the skin. The effect was dose-dependent; the more chlorine in the water the higher the water loss. The concentrations of chlorine that caused the damage were similar to what it used in swimming pools. In this study the exposure was limited to 10 minutes. Longer exposure to chlorine probably leads to more severe damage.
This study was done with atopic dermatitis (AD) patients, but my guess is that the same study with acne patients would find similar results. The study also found that chlorine damaged the skin of AD patients more than it did healthy controls. Not surprising and it just goes on to show that problem skin is more sensitive to environmental toxins and chemicals.
So, what to make of this? This is one more example of why you need to be careful with what you expose your skin to. There’s no reason to be paranoid, but it pays to be careful. Also, do use moisturizer (shown to repair skin barrier function) after any such exposures.