You should look for traces of the insects in the folds of your mattresses, box springs and other places where they are likely to hide. You might be able to find their papery skins, which get cast off after molting and look like popcorn kernels but are smaller and thinner, Harlan said. They also leave small, dark-colored spots from the blood-filled droppings they deposit on mattresses and furniture. If you can touch the spot with a water-soaked towel and it runs a rusty, reddish color, you're probably looking at a fresh drop of bedbug feces, Harlan said.
Blood spots found on one’s sheets, bites and the presence of bed bug feces and cast skins are some of the indications of a bed bug infestation. Bites are commonly found on the parts of the body that are more likely to be exposed to bed bugs during sleep – the hands, neck, face, shoulders, legs and arms. While not always the case, bed bug bites are often grouped together in a small area and at times may occur in a line or a zigzag pattern. Bites normally look like small, flat or raised areas that may become inflamed, itchy, red or blistered. Bed bug bite reactions don’t always appear immediately after you’re bitten and may take a few days to begin causing symptoms. However, not everyone reacts to bed bug bites in the same manner.