I'd guess it's a function of the composition of the dust. It might abrade blade leading edges, or if it's a "right" (wrong) material could conceivably melt in the hot sections and adhere to components, block cooling paths, etc.
I think it's unlikely it would be a direct threat to either loss of thrust or engine loss itself, but you could be looking at an earlier removal as a consequence. I doubt a single pass would do much, given there are aircraft operating in "dusty" environments on a regular basis.