My little boy has a white spot with a black dot on top of his foot. any idea what it is?

Possible halo nevus: Although this could be many different things and requires an exam to make a formal diagnosis, it sounds typical for a halo nevus, thought to be an auto immune reaction similar to vitiligo in which lymphoctes attack the melanocytes of the nevus It is most commonly seen on the trunk in adolescents and although it can be removed, it is usually benign and may go through stages.from a halo to white.