  In this article we analyze the role of an external electric field, in the
weak field approximation, on $\pi$-$\pi$ scattering lengths. The discussion is
presented in the frame of the linear sigma model. To achieve this, we take into
account all one-loop corrections in the $s$, $t$, and $u$ channels associated
with the insertion of a Schwinger propagator for charged pions, focusing on the
region characterized by small values of the electric field. Furthermore, one of
the novelties of our work is the explicit calculation of box diagrams, which
were previously overlooked in discussions regarding magnetic corrections. It
turns out that the electric field corrections have an opposite effect with
respect to magnetic corrections calculated previously in the literature.
