Probiotics do wonders to rebalance the gut flora which is a large part of our immune system. And since eczema is an autoimmune disorder, that means your immune system is basically attacking your body's own tissues out of confusion (since it's so out of balance and confused).
I know they definitely helped me too.
However, I HIGHLY recommend you try fermented foods instead. Probiotics pale in comparison to the power and bacterial concentration of things like sauerkraut, kefir and kimchi. Plus, probiotics usually contain a somewhat narrow spectrum of strains like acidophilus or rhamnosus etc. While natural fermented probiotic foods can contain millions of them.
You'll get much better results (and much cheaper too) when you make the switch. I definitely kicked myself when I did.