Flea bites are caused by the parasitic insect, the flea. The most common species of flea in the US is the cat flea, Ctenocephalides felis. Signs and symptoms of flea bites in humans include itching, hives, a rash with bumps, red spots with a "halo," and swelling around the bite. Treatment for flea bites includes over-the-counter medicine and natural and home remedies to relieve and soothe itching and inflammation. The redness of a flea bite can last from a few hours to a several days.
Unlike those of other insects, bed bug bites may sometimes appear in tight lines of multiple, small, red marks where multiple bed bugs have fed along an exposed area. Bed bug bites can cause itchiness. Initially, a victim may detect a slight burning sensation. The burning area then develops red bumps, known as papules or wheals (rash). In extreme cases, bites may swell dramatically or turn into blister-like skin inflammations.