Bed bugs are obligatory bloodsucking. They have mouth parts that saw through the skin, and inject saliva with anticoagulants and painkillers. Sensitivity of humans varies from extreme allergic reaction to no reaction at all (about 20%). The bite usually produces a swelling with no red spot, but when many bugs feed on a small area, reddish spots may appear after the swelling subsides. Bedbugs prefer exposed skin, preferably the face, neck, and arms of a sleeping person.
Bedbugs do, however, have a unique bite pattern. Although some bites may appear alone, most bites occur in a row of three to five bites (termed "breakfast, lunch, and dinner") or in a cluster of red bumps (a rash called bedbug dermatitis). The bites often appear in a zig-zag formation, but may appear in a straight line if the bugs bite you in the morning.
Both of these types of Hemiptera are sensitive to extreme temperatures. It may be necessary to rid the infestation by exposing the area to extreme heat or cold; they are most comfortable in temperatures around eighty degrees Fahrenheit. Raising the temperature to ninety-seven to ninety-nine degrees may kill off a significant portion of the population.