Red, itchy, raised bumps in a line or cluster are symptoms of bed bug bites. Bed bugs are not particular about the areas of skin they bite, attacking any area of skin left exposed while sleeping. Since these symptoms are similar to the bites of other insects such as mosquitoes and fleas, the best way to identify a bite as belonging to a bed bug is to find the bed bug. Bed bugs are small, brown bugs about the size of a tiny seed. They become swollen and red when they drink blood, which occurs mainly at night.
Besides the physical symptoms associated with the bite of a bed bug, other signs of an infestation include small blood spots or dark fecal spots on sheets and a musty odor from the bug's scent glands. If not eliminated, bed bugs can spread to other areas of the home.