Bed bugs often hide in seams, folds and crevices of mattresses, box springs, bed frames and headboards. A thorough inspection requires dismantling the bed so that upper and lower seams and surfaces can be examined. Things to look for are the bugs themselves, shed skins of the nymphs (immature bed bugs), and the blackish fecal spots. The dark spots of dried bed bug excrement are often present along mattress seams or wherever the bugs have resided. Box springs afford many places for bed bugs to hide, especially along the upper seams and underneath, where the bottom edge of the box rests on the frame. If an underlying dust cover is present, it may have to be removed to gain access for inspection and possible treatment. Successful treatment of mattresses and box springs can be difficult, however, and infested ones may need to be discarded or encased in a protective cover.
Unlike those of other insects, bed bug bites may sometimes appear in tight lines of multiple, small, red marks where multiple bed bugs have fed along an exposed area. Bed bug bites can cause itchiness. Initially, a victim may detect a slight burning sensation. The burning area then develops red bumps, known as papules or wheals (rash). In extreme cases, bites may swell dramatically or turn into blister-like skin inflammations.