  Non-Hermitian systems have provided a rich platform to study unconventional
topological phases.These phases are usually robust against external
perturbations that respect certain symmetries of thesystem. In this work, we
provide a new method to analytically study the effect of disorder, usingtools
from quantum field theory applied to discrete models around phase-transition
points. Weinvestigate two different one-dimensional models, the paradigmatic
non-Hermitian SSH model andas-wave superconductor with imbalanced pairing.
These analytic results are compared to numericalsimulations in the discrete
models. An universal behavior is found for the two investigated models,namely
that the systems are driven from a topological to a trivial phase for disorder
strengths equalto about four times the energy scale of the model.
