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Skip Navigation LinksPennsylvania Department of Health > My Health > A-Z Health Topics > A-D > Bed Bugs Fact Sheet


Bed bugs (Cimex lectularius) are small insects that feed on human blood. They are usually active at night when people are sleeping. Adult bed bugs have flat, rusty red-colored oval bodies. When they feed, their bodies swell and become brighter red. About the size of an apple seed, bed bugs are big enough to be easily seen but often hide in cracks in furniture, floors or walls. They can travel over 100 feet in a night but tend to stay within 8 feet of where people sleep. They can live for several months without food or water.
Bed bugs are found around the world, in both developing and developed countries. Bed bugs have been found in apartments, shelters, rooming houses, buses, trains, dorm rooms, schools, offices, cruise ships and hotels, including five-star hotels and resorts. Their presence is not associated with cleanliness or the lack of cleanliness.
Signs and Symptoms
Most bed bug bites are initially painless, but turn into large, itchy skin welts after one to several days. Bite marks may be random or appear in a straight line.
Bed bug infestations are usually identified by the tell-tale bite marks on a person’s body. However, the following signs will also help identify an infestation:
  • Bed bugs’ exoskeletons after molting;
  • Bed bugs in the fold of mattresses and sheets;
  • Rusty-colored blood spots due to the blood-filled fecal material they excrete on the mattress or other furniture; and
  • A sweet musty odor.
Risk Factors
Everyone is at risk for getting bed bugs when visiting an infested area. Those who travel frequently and share living and sleeping quarters where other people have previously slept have a higher risk of encountering bed bugs. Bed bugs are usually transported from place to place as people travel. They travel in the seams and folds of luggage, overnight bags, folded clothes, bedding, furniture and anywhere else where they can hide. Most people do not realize they are transporting stow-away bed bugs as they travel from location to location, infesting areas as they travel.
Although bed bugs are a nuisance, they are not known to spread disease, and bed bug bites are not dangerous. However, some people may have an allergic reaction that requires medical attention. Other people may have excessive scratching that leads to a secondary skin infection. Some may develop anxiety and/or insomnia.
The best treatment for a bite is to avoid scratching the area and to apply antiseptic creams or lotions and take an antihistamine.
Bed bug infestations are commonly treated by insecticide spraying. If you suspect that you have an infestation, contact your landlord or a professional pest control company that is experienced with treating bed bugs.
The best way to prevent bed bugs is to avoid spending time in and bringing belongings into an infested area. When staying in a new place, check for signs of an infestation immediately upon entry and do not bring belongings in until you are confident the area is free of bed bugs.
Additional Information
Centers for Disease Control and Prevention:
Environmental Protection Agency:
This fact sheet provides general information. Please contact your physician for specific clinical information. 

Last reviewed/updated: April 7, 2016