I am Eritrean traveling from Sudan to Italy. I have got a Schengen visa to Italy, my question is, can I transit through UK without any other additional visa, mean with that Italian schengen visa only.
No, you can't. The United Kingdom is not part of the Schengen Agreement, and Eritreans have to apply for a direct airside transit visa (DATV). You can see the requirements for a DATV at the Home Office website.