This is mainly because the first step in an allergic reaction is the recognition of antigens (allergens), and the B cells of immune cells recognise substances such as peptides, proteins and nucleic acids; T cells only recognise antigen fragments (peptides) bound to MHC antigens on the surface of antigen presenting cells; high protein foods are absorbed and digested and metabolised to produce proteins, peptides and other substances, which are antigens recognised by both T and B cells, and beef and seafood are high protein foods, therefore, they are manifested as some people are allergic to beef and seafood, which cause allergic reactions and itchy skin symptoms after consumption.