We develop general criteria that ensure that any non-zero solution of a given
second-order difference equation is differentially transcendental, which apply
uniformly in particular cases of interest, such as shift difference equations,
q-dilation difference equations, Mahler difference equations, and elliptic
difference equations. These criteria are obtained as an application of
differential Galois theory for difference equations. We apply our criteria to
prove a new result to the effect that most elliptic hypergeometric functions
are differentially transcendental