Not only can it affect it, it can CURE it. I had a patch of eczema on the back of my knee for about 10 years. Sometimes it would itch mildly, sometimes it would itch so bad I would scratch it raw. But in some form or another it was there for 10 years. When I started snorkeling I noticed that, after a day of snorkeling, it didn't itch and felt softer to the touch. The itching came back but when I went snorkeling a few days later I noticed the same thing...didn't itch for a few days, and it felt noticably softer to the touch. Eventually I took up SCUBA diving and after a couple of months of diving on a weekly basis the eczema was gone. Several dives cured what numerous prescriptions and "miracle cures" could not. Not sure exactly what to attribute this to; maybe the salt, maybe the plant particles, maybe the microorganisms, maybe maybe maybe-not really sure. But whatever the reason(s), I feel sure that the sea water is responsible for ridding me of my eczema; hopefully you will have the same result!