  The universality of the QCD equation of state near the critical point is
expressed by mapping pressure as a function of temperature $T$ and baryon
chemical potential $\mu$ in QCD to Gibbs free energy as a function of reduced
temperature $r$ and magnetic field $h$ in the Ising model. The mapping
parameters are, in general, not universal, i.e., determined by details of the
microscopic dynamics, rather than by symmetries and long-distance dynamics. In
this paper we point out that in the limit of small quark masses, when the
critical point is close to the tricritical point, the mapping parameters show
universal dependence on the quark mass $m_q$. In particular, the angle between
the $r=0$ and $h=0$ lines in the $(\mu,T)$ plane vanishes as $m_q^{2/5}$. We
discuss possible phenomenological consequences of these findings.
