Pay attention to when the bites occur. Consider, for example, if you notice the bites after waking up when previously you hadn't noticed them. However, this can also be difficult to determine because each person's reaction time can vary significantly. Symptoms that result from the bite can manifest at any point from a couple of hours to more than a week after the bite occurred.
The size of bed bug bites varies with a number of different factors. Bed bugs inject an anti-coagulant along with their saliva when they pierce the skin to take a blood meal. This anti-coagulant is mostly responsible for how a person reacts to the bite and determines the size of the bug’s bite. Since people will have various sensitivities to the bed bug’s bite, the size of the bite will vary, as well. Another factor that influences the size of a bed bug reaction is the number of times a person is bitten. Bite reactions of people bitten many times are also variable, and their response may be either more or less intense as the number of bites increases.