This may be an old issue, but is still worthy of note.
Parents who tend to over protect their children by obsessive washing need to be educated that it is very bad for their children's health. A research conducted positively indicates a direct link between the frequency of washing and the incidence of eczema and wheezing. The more the children are washed the more likely they are to have the conditions, particularly severe eczema, lending more credence to the "hygiene hypothesis", which suggests that too much cleanliness inhibits the child's natural immune responses to everyday bacteria. Children who are washed the most are two and half times more likely to have severe eczema as well as running an increased risk of asthma.
Is it in order to assume that coming into contact with simple grime and dirt may be good for the children? The research pointed out that lack of such contact, perhaps due to the fact that children spend more time indoors and parents use more anti-bacterial products around the home, may lead to allergies and conditions, such as eczema and asthma.
So this answers my question why many children here have skin disorders. It is not because of the salty water, but because of parents who are obsessive with cleanliness.