Can consistent use of claritin (loratadine) d cause a very runny - drippy nose?

Yes: Overuse of Pseudoephedrine (the d in claritan d) can cause rebound vasodilation and increase the amount of mucous your nose pours out. Using a product long term with Pseudoephedrine can make matters worse. Shouldn't use them more that a week or two at most. Can continue the plain claritan, but may need to wean off the pseudoephedrine. Ask doc about a nasal steroid in place of it.