In some cases, you might also notice that your skin becomes a somewhat yellowish color. This is due to the breakdown of the fragile red blood cells and the release of bilirubin. This is a somewhat reddish/brown substance that is created in the liver.
If this builds up too much, then you might notice that your skin and eyes take on a mildly yellow tinge.
Of course, jaundice can be a result of kidney failure, in which case the body is not removing the toxins that form urine from the blood effectively. This results in a yellowish discoloration, as well as a feeling of itchiness under the skin.
Likewise, paleness is a symptom of iron deficiency and other conditions. Therefore, looking for a combination of these symptoms might be the most useful way to implicate B12 anemia.