  We discuss recent advances on QCD chiral symmetry restoration at finite
temperature, within the theoretical framework of Effective Theories. $U(3)$
Ward Identities are derived between pseudoscalar susceptibilities and quark
condensates, allowing to explain the behaviour of lattice meson screening
masses. Unitarized interactions and the generated $f_0(500)$ thermal state are
showed to play an essential role in the description of the transition through
the scalar susceptibility
