Flea
Flea bites can easily be mistaken for allergies or mosquito bites because the bitten spots also look red and swollen. However, unlike mosquitoes, these insect bites are very painful, and the itch is much worse.
Fleas usually attack the legs, and only a sleeping person can be a victim. One insect can bite several times, so the distance between the red spots is usually from 0.5 to 1 inch (1 to 2 cm). Fleas transmit many serious infections.