"The participants were randomly assigned to apply a vitamin B12 cream (containing 0.07% cyanocobalamin, a form of vitamin B12) to affected areas on one side of the body, and a placebo cream to affected areas on the other side of the body two times per day for eight weeks."
"For all participants, the extent and severity of eczema were significantly less on the side of the body treated with the vitamin B12 cream than on the side treated with the placebo cream. Both the doctors and the study participants rated the vitamin B12 cream as superior to the placebo cream in effectiveness and tolerability. Only a few mild adverse reactions (local skin irritation) were associated with use of the vitamin cream.
The results of this study suggest that topical application of vitamin B12 is a safe and effective eczema treatment."
http://bastyrcenter.org/content/view/409/