In this paper we deal with parabolic problems whose simplest model is {u' - Delta(p)u + B vertical bar del u vertical bar(p)/u = 0 in (0, T) x Omega, u(0, x) = u(0)(x) in Omega, u(t, x) = 0 on (0, T) x partial derivative Omega, where T > 0, N >= 2, p > 1, B > 0, and u(0) is a positive function in L-infinity(Omega) bounded away from zero. (C) 2015 Elsevier Ltd. All rights reserved.