An engorged female bed bug (Cimex lectularius) with eggs, discovered in the screw hole of a wooden bed frame. copyright - Thomas Oldani 2009

Bed bugs are elusive and usually nocturnal, which can make them hard to spot. They often lodge unnoticed in dark crevices, and eggs can be nestled in fabric seams. Aside from bite symptoms, signs include fecal spots, blood smears on sheets, and molts. Bed bugs can be found singly but often congregate once established.

One of the easiest ways to identify a bed bug infestation is by the evidence of bite marks that appear on the face, neck, arms, hands, and any other body parts. However, these bite marks may take as long as 14 days to develop in some people so it is important to look for other clues when determining if bed bugs have infested an area. These signs may include the exoskeletons of bed bugs after molting, bed bugs in the fold of mattresses and sheets, a sweet musty odor, and rusty-colored blood spots from their blood-filled fecal material that is often excreted on the mattress or nearby furniture.