  Five-dimensional Kaluza-Klein theory with an Einstein-Gauss-Bonnet Lagrangian
induces nonlinear corrections to the four-dimensional Maxwell equations, which
however remain second order. Although these corrections do not have effect on
the purely electric or magnetic monopole solutions for pointlike charges, they
affect the dyonic solutions, smoothing the electric field at the origin for
negative values of the Gauss-Bonnet coupling constant. We investigate these
solutions in flat space, and then extend them in the presence of gravity,
obtaining charged black hole solutions that generalize the Reissner-Nordstr\"om
metric.
