  We discuss the effect of QED corrections in the evolution of polarized parton
distributions. We solve the corresponding evolution equations exactly to ${\cal
O}(\alpha )$ and ${\cal O}(\alpha_s^2)$ in Mellin $N$-space, extending the
available techniques for pure QCD evolution. To accomplish this, we introduce,
for the first time, the Altarelli-Parisi polarized kernels at LO in QED.
Furthermore, we perform a phenomenological analysis of the QED effects on
polarized parton distributions (pPDFs), proposing different scenarios for the
polarized photon density. Finally, we quantify the impact of the corresponding
QED contributions to the polarized structure function $g_1$. We show that the
relative corrections to both the pPDFs and the $g_1$ structure function are
approximately at the few percent level, which is the order of magnitude
expected considering the value of $\alpha$.
