My 14 month old has eczema. It started at about 5-6 months. If you saw him today, you may not want my advice because he doesn't look all that great. But he has looked a lot worse. And sometimes he looks better. It's just taking a while to figure out what triggers it.
First of all, I'd strongly recommend visiting an allergist. We started with dermatologists, and they just wanted to give me really strong prescriptions rather than figuring out what triggered it. The allergist did a scratch test and helped me figure out where we should start with eliminating potential triggers.
Just because it started now doesn't mean that it's something new. Many babies develop eczema at about that age to things they've been exposed to since birth. Eczema is more commonly triggered by things you touch, rather than by food, but food allergies can cause it. And the baby doesn't have to have any typical allergy symptoms, like hives, diaper rash, upset tummy, etc.
We used Aquaphor for a while, but DS eventually became sensitive to it. We've been using Gentle Naturals Baby Eczema Cream for several months now and love it. They have it near the diaper ointments at Target. I haven't been able to find it at Wal-Mart. We put it on AT LEAST 6 times/day. When he's having an outbreak, I do it when he wakes up, when he goes to sleep, and every even hour (8:00, 10:00, etc.).
So far, we've identified eggs, corn, chlorine, and polyester and other synthetic fabrics as triggers. He's 14 months old and gets about 95% of his calories from breastmilk because every time I give him food he flares up again. Dairy and soy are the top 2 allergins in the US. There are meat-based formulas available. They're expensive, but you may want to try one for a month or so and see what happens. Corn is also in the top 10 list of allergies, and I think that all formulas are sweetened with corn syrup. I usually recommend that people withhold solids as long as possible and use breastmilk/formula for the major source of food for a long time, but you may want to talk to your doctor about not doing that. It can be so hard to eliminate everything when formula contains so many allergins. At about 9 months, your doctor may be comfortable with using goat's milk that you fortify with vitamins and minerals.
Good luck! It can be very hard to figure out exactly what's going on. The good news is that he'll probably outgrow it.