Signs that someone has bed bugs:
If they wake up with itchy areas they didn’t have when they went to sleep, particularly if they got a used bed or other used furniture around the time the bites started
Blood stains on your sheets or pillowcases
Dark or rusty spots of bed bug excrement on sheets and mattresses, bed clothes, and walls – looks like an ink spot from a black pen
Bed bug fecal spots, egg shells, or shed skins in areas where bedbugs hide
An offensive, musty odor from the bugs’ scent glands