  We analyze how excitations affect the entanglement entropy for an arbitrary
entangling interval in a 2d conformal field theory (CFT) using the holographic
entanglement entropy techniques as well as direct CFT computations. We
introduce the excitation entanglement entropy \Delta_h S, the difference
between the entanglement entropy generic excitations and their arbitrary
descendants denoted by h. The excitation entanglement entropy, unlike the
entanglement entropy, is a finite quantity (independent of the cutoff), and
hence a good physical observable. We show that the excitation entanglement
entropy is governed by a second order differential equation sourced by the one
point function of the energy momentum tensor computed in the excited background
state. We analyze low and high temperature behavior of the excitation
entanglement entropy and show that \Delta_h S grows as function of temperature.
We prove an "integrated positivity" for the excitation entanglement entropy,
that although \Delta_h S can be positive or negative, its average value is
always positive. We also discuss the mutual and multipartite information with
generic excitations.
