Vitamin B12 relieves itching

The strong antipruritic effect of vitamin B12 has been demonstrated by six German dermatologists in a very simple experiment including 49 patients.
The scarified patients were each given two tubes of cream. One was a neutral moisturizer while the other contained vitamin B12 which is normally only available as tablets or as solutions for injections. In the following eight weeks, the patients smeared one of the creams onto one body half and the other cream onto the other body half. After the eight weeks, both patients and doctors evaluated the results.
The effect was plausible. In about 60% of the cases, the vitamin B12 cream achieved a "good" or "very good" result according to both doctors and patients. On the side of the body that had been smeared with the plain moisturizer, however, the results were invariably moderate or poor. In this case doctors and patients also agreed on the outcome.
The vitamin B12 cream was very well tolerated and is completely harmless. Its mode of operation is believed to be the vitamin in certain regards being an effective antioxidant that neutralizes NO (nitric oxide) in infected tissues. It is known that when medically blocking the production of NO in asthmatic eczema, the itching and rash decrease. What is new is that the same effect in this simple way is achieved by blocking NO once it has been produced.
Itching is also a problem in many other skin diseases, and many elderly people suffer from chronic itching. Whether the vitamin has an effect on other conditions involving itching is unknown. An estimated 10% of elderly people in Britain suffer from vitamin B12 deficiency.
Reference:
Stucker M, Pieck C, Stoerb C, Niedner R, Hartung J, Altmeyer P Topical vitamin B(12)-a new therapeutic approach in atopic dermatitis-evaluation of efficacy and tolerability in a randomized placebo-controlled multicentre clinical trial. Br J Dermatol. 2004;150(5):977-83.