Bed bug bites usually cause red, itchy welts on the skin, and they are often clustered together, according to Orkin. They are commonly found on areas of the body that are most likely to be exposed while sleeping, such as the face, the neck, the arms and the hands.
Bite marks usually do not appear right away, and they can take several days to show symptoms, if at all, explains eMedicineHealth. The reaction to bites can be different for each person, and it can also depend on how long the bed bugs were able to feed and how many there were. Mild reactions to bites can heal in just a couple of weeks, while harsher reactions can develop into a rash.