Is my client correct that his taking chelated zinc daily (22 mg of zinc glycinate from Solgar) is preventing symptoms of eczema, which he says always flares up if he stops taking the zinc for a while? Would this be of universal benefit for eczema sufferers?

His observations are accurate and being interpreted correctly, that zinc for him is of therapeutic benefit to resolve the eczema symptoms. It is also a general characteristic for all who have eczema that having a zinc deficiency will cause symptoms to be more evident and to worsen. Whether taking a zinc supplement alone will be enough for all symptoms to fade will be a variable that is true for some and not for others. But it is a useful example to report, as it is easy for people to try this approach to see if it brings benefit. In some cases, it will allow withdrawing medication successfully, which has some downside risk as well as greater cost.