There were no sets built for the film. It was all shot on location at one large Italian villa. In fact the movie itself was written to be shot around that particular location.
Director Lamberto Bava said in an interview that he liked the American title for the film (A Blade in the Dark) much better than the Italian title (House of Dark Stairs). Bava felt that particular title captured the film much better.
Director Lamberto Bava worked as an assistant to Dario Argento on the film Ténèbres (1982) two years before making A Blade in the Dark. As many critics noted, Tenebre was an influence on this film in terms of both plot and visual style.
A Blade in the Dark has a number of reoccurring motifs in its chilling music score: most notably the shrill note of a glass armonica whenever the box cutter or a knife appears on screen.
Stanko Molnar, who plays Giovanni, starred in Lamberto Bava's previous film, Baiser macabre (1980). It was the director's debut prior to making A Blade in the Dark.