It is hard to tell if you’ve been bitten by a bed bug unless you find bed bugs or signs of infestation. When bed bugs bite, they inject an anesthetic and an anticoagulant that prevents a person from realizing they are being bitten. Most people do not realize they have been bitten until bite marks appear anywhere from one to several days after the initial bite. The bite marks are similar to that of a mosquito or a flea — a slightly swollen and red area that may itch and be irritating. The bite marks may be random or appear in a straight line. Other symptoms of bed bug bites include insomnia, anxiety, and skin problems that arise from profuse scratching of the bites.
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.
Reactions to bed bug bites vary among individuals. Many persons show no signs of bites. Others don’t realize they’ve been bitten until redness and swelling appear around the bite, sometimes with intense itching. Some exhibit inflamed swollen spots that may occur in linear series or have a rash-like appearance. Such bite marks, when they appear, may not show for several days after the person is bitten.