I would question your diapers. EVERYONE I know who has used bumGenius! Dipes has switched within a year of using htem to something else, like Fuzzi Bunz. The Microfiber liner over time holds things in and children get severe diaper rashs and reactions to it. I know at least 15 people who started with bumGenius! diapers and have switched within a yaer to something else.
We used Fuzzi Bunz exclusively, and never had a problem.
If your son has eczema, you need to find the source of he problem. Is usually dairy protein, and if you are using formula... cna't really do much about it. My oldest son suffers eczema and psoriasis, and after years of creams, steroids, oral meds, and suffering from open sores, bleeding, skin falling off, crying and in pain, we finally found out how to cure eczema, form the inside out. Eczema lives in teh colon as a bacteria, and it presents itself on the skin. To get rid of it, you need to eliminate the problem (usually a food sensitivity or in your case with the BG diapers, external). We also give our son (and all of us, its good for you) Acidophilus. Its a probiotic, so it replaces the bad bacteria with the good, and takes care of the eczema. Its safe for everyone, and good for everyone.
When you start using it, the eczema will move around abit trying to escape it. Then it will go away or get very very minimal. If he's itchy o the skin is sore/flaky, get some TEA TREE OIL. You can find it for less than $2 in Wal Mart by the band aids. ITs an antifungal, since eczema on the skin is a fungus. Put 10 drops into a bowl of warm water, dip a washcloth and lightly wring it out, and place it over the eczema for a few minutes. This will reduce the itching, take care of the fungus, and make the skin feel good.