I came across a very interesting story: Twenty years ago Karsten Klingelhöller, then a medical student in Germany, developed a cream containing mainly vitamin B12 and avocado oil to help his girlfriend with psoriasis. This cream turned out to be very effective not only in the treatment of psoriasis but also for eczema. Since then Mr. Klingelhöller tried unsuccessfully to bring this cream onto the market, even though there has been a small clinical study demonstrating its effectiveness [1,2]. In 2009 the German television station WDR produced a documentary about the story of this cream with the title “Heilung unerwünscht” (“Healing not wanted”). This documentary claims that the reason, why this cream is not available to buy, is that many of the large pharmaceutical companies produce much more expensive products (e.g. cortisone containing creams, elidel, etc) which give them bigger bucks than a cheap cream of similar effectiveness but without the side effects.
The cream did come onto the marked shortly after this documentary aired and can now be bought under the name Mavena B12 (its first name was Regividerm) (It is not clear if the documentary was a smart PR move, or if the production finally started because of the documentary. Klaus Martens, the journalist who made this documentary and wrote a book about this case, lost his job at the television station shortly after. update: I just found out that Klaus Martens did no loose his job. He was only temporarily suspended). However, the cream is not approved as a medicine, but instead is sold as a medical product (this means there have not been done all clinical trails necessary to prove its safety and effectiveness, but more has been done than for cosmetic products).
The recipe of the cream is widely published online, e.g. on Esowatch, reflecting the original idea of mixing vitamin B12 with avocado oil, water and an emulsifier. The reasons why this cream might indeed be effective is that vitamin B12 binds and neutralizes nitrogen monoxide, which plays a role in acute inflammations. However, this also means that vitamin B12 does not treat the cause of the inflammation but rather might prevent whatever aggravates the inflammation and itchiness. So this cream is certainly not a cure but might help with the itchiness.
There are two main criticisms about this cream: First, the documentary seems very much like a smart PR move to market the cream. The film presents the story in the light of David against Goliath without critically questioning the cream itself. Some of the doctors and scientists interviewed for this film retracted some of the things they said after the film aired. The second critique, which I think is the more serious one, addresses the clinical studies [1,2]. Not only is the number of subjects very small, but both studies mention the support of Regeneratio Pharma AG, Wuppertal, Germany in the acknowledgements. Regeneratio Pharma AG is the company that owns the patent to the cream, and one might wonder how truly independent this studies are.
So, is this again an empty promises? Do we again stand before a product that is supposed to miraculously help against eczema? Is there again someone just making money, or not so much money, on the expense of the very large number of desperate eczema sufferers? I am desperate. I just called my pharmacy and ordered the cream. 100g of hope for 28.95 Euros.
 M. Stücker et al.: Topical vitamin B-a new therapeutic approach in atopic dermatitis-evaluation of efficacy and tolerability in a randomized placebo-controlled multicentre clinical trial, The British journal of dermatology, 2004 May; Volume 150, Issue 5, S.977-983.