Symptoms may not appear until some days after the bites have occurred. Reactions often become more brisk after multiple bites due to possible sensitization to the salivary proteins of the bed bug. The skin reaction usually occurs in the area of the bite which is most commonly the arms, shoulders and legs as they are more frequently exposed at night. Numerous bites may lead to an erythematous rash or urticaria.
Bed bugs are active mainly at night. During the daytime, they prefer to hide close to where people sleep. Their flattened bodies enable them to fit into tiny crevices--especially those associated with mattresses, box springs, bed frames and headboards. Bed bugs do not have nests like ants or bees, but do tend to congregate in habitual hiding places. Characteristically, these areas are marked by dark spotting and staining, which is the dried excrement of the bugs. Also present will be hatched and un-hatched eggs, the tannish shed skins of maturing nymphs, and the bugs themselves. Another possible sign are rusty or reddish smears on bed sheets or mattresses from crushed engorged bed bugs. Although it’s often stated that bed bugs have a telltale “buggy” odor, the smell is seldom evident except in extreme infestations and should not be relied upon for detection.
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.