Bed bugs are insects from the genus Cimex that feed on human blood, usually at night. Their bites can result in a number of health impacts including skin rashes, psychological effects, and allergic symptoms. Bed bug bites may lead to skin changes ranging from invisible to small areas of redness to prominent blisters. Symptoms may take between minutes to days to appear and itchiness is generally present. Some individuals may feel tired or have a fever. Typically, uncovered areas of the body are affected and often three bites occur in a row. Bed bugs bites are not known to transmit any infectious disease. Complications may rarely include areas of dead skin or vasculitis.
Bed bug bites are caused primarily by two species of insects: Cimex lectularius (the common bed bug) and Cimex hemipterus, found primarily in the tropics. Their size ranges between 1 and 7 mm. They spread by crawling between nearby locations or by being carried within personal items. Infestation is rarely due to a lack of hygiene but is more common in high-density areas. Diagnosis involves both finding the bugs and the occurrence of compatible symptoms. Bed bugs spend much of their time in dark, hidden locations like mattress seams, or cracks in a wall.
Treatment is directed towards the symptoms. Eliminating bed bugs from the home is often difficult, partly because bed bugs can survive up to a year without feeding. Repeated treatments of a home may be required. These treatments may include heating the room to 50 °C (122 °F) for more than 90 minutes, frequent vacuuming, washing clothing at high temperatures, and the use of various pesticides.
Bed bugs occur in all regions of the globe. Rates of infestations are relatively common, following an increase since the 1990s. The exact causes of this increase are unclear; theories including increased human travel, more frequent exchange of second-hand furnishings, a greater focus on control of other pests, and increasing resistance to pesticides. Bed bugs have been known human parasites for thousands of years.
Bed Bug Bites
Individual responses to bites vary, ranging from no visible effect (in about 20–70%), to small flat (macular) spots, to the formation of prominent blisters (wheals and bullae) along with intense itching that may last several days. Vesicles and nodules may also form. The bites often occur in a line. A central spot of bleeding may also occur due to the release of blood thinning substances in the bug's saliva.
Symptoms may not appear until some days after the bites have occurred. Reactions often become more brisk after multiple bites due to possible sensitization to the salivary proteins of the bed bug. The skin reaction usually occurs in the area of the bite which is most commonly the arms, shoulders and legs as they are more frequently exposed at night. Numerous bites may lead to a red rash or hives.
Serious infestations and chronic attacks can cause anxiety, stress, and sleep difficulties. Development of refractory delusional parasitosis is possible, as a person develops an overwhelming obsession with bed bugs.
Infestation is rarely caused by a lack of hygiene. Transfer to new places is usually in the personal items of the human they feed upon. Dwellings can become infested with bed bugs in a variety of ways, such as:
- Bugs and eggs inadvertently brought in from other infested dwellings on a visiting person's clothing or luggage;
- Infested items (such as furniture especially beds or couches, clothing, or backpacks) brought in a home or business;
- Proximity of infested dwellings or items, if easy routes are available for travel, e.g. through ducts or false ceilings;
- Wild animals (such as bats or birds) that may also harbour bed bugs or related species such as the bat bug;
- People visiting an infested area (e.g. dwelling, means of transport, entertainment venue, or lodging) and carrying the bugs to another area on their clothing, luggage, or bodies. Bedbugs are increasingly found in air travel.
Though bed bugs will opportunistically feed on pets, they do not live or travel on the skin of their hosts, and pets are not believed to be a factor in their spread.
Bed bugs can exist singly, but tend to congregate once established. Although strictly parasitic, they spend only a tiny fraction of their lifecycles physically attached to hosts. Once a bed bug finishes feeding, it relocates to a place close to a known host, commonly in or near beds or couches in clusters of adults, juveniles, and eggs—which entomologists call harborage areas or simply harborages to which the insect returns after future feedings by following chemical trails. These places can vary greatly in format, including luggage, inside of vehicles, within furniture, among bedside clutter—even inside electrical sockets and nearby laptop computers. Bed bugs may also nest near animals that have nested within a dwelling, such as bats, birds, or rodents. They are also capable of surviving on domestic cats and dogs, though humans are the preferred host of C. lectularius.
Bed bugs can also be detected by their characteristic smell of rotting raspberries. Bed bug detection dogs are trained to pinpoint infestations, with a possible accuracy rate between 11% and 83%. Homemade detectors have been developed.
To prevent bringing home bed bugs, travelers are advised to take precautions after visiting an infested site: generally, these include checking shoes on leaving the site, changing clothes outside the house before entering, and putting the used clothes in a clothes dryer outside the house. When visiting a new lodging, it is advised to check the bed before taking suitcases into the sleeping area, and putting the suitcase on a raised stand to make bedbugs less likely to crawl in. An extreme measure would be putting the suitcase in the tub. Clothes should be hung up or left in the suitcase, and never left on the floor. The founder of a company dedicated to bedbug extermination said that 5% of hotel rooms he books into were infested. He advised people never to sit down on public transport; check office chairs, plane seats, and hotel mattresses; and monitor and vacuum home beds once a month.
Treatment of bedbug bites requires keeping the person from being repeatedly bitten, and possible symptomatic use of antihistamines and corticosteroids (either topically or systemically). There however is no evidence that medications improve outcomes, and symptoms usually resolve without treatment in 1–2 weeks.
Avoiding repeated bites can be difficult, since it usually requires eradicating bed bugs from a home or workplace; eradication frequently requires a combination of pesticide and non-pesticide approaches. Pesticides that have historically been found to be effective include pyrethroids, dichlorvos and malathion. Resistance to pesticides has increased significantly over time, and there are concerns about harm to health from their use. Mechanical approaches, such as vacuuming up the insects and heat-treating or wrapping mattresses have been recommended.
Once established, bed bugs are extremely difficult to get rid of. This frequently requires a combination of non-pesticide approaches and the use of insecticides.
Mechanical approaches, such as vacuuming up the insects and heat-treating or wrapping mattresses, are effective. An hour at a temperature of 45 °C (113 °F) or over, or two hours at less than −17 °C (1 °F) kills them. This may include a domestic clothes drier for fabric or a commercial steamer. Bed bugs and their eggs will die on contact when exposed to surface temperatures above 180 °F (82 °C) and a steamer can reach well above 230 °F (110 °C). A study found 100% mortality rates for bed bugs exposed to temperatures greater than 50 °C (122 °F) for more than 2 minutes. The study recommended maintaining temperatures of above 48 °C (118 °F) for more than 20 min to effectively kill all life stages of bed bugs, and because in practice treatment times of 6 to 8 hours are used to account for cracks and indoor clutter. This method is expensive and has caused fires. Starving bedbugs is not effective, as they can survive without eating for 100 to 300 days, depending on temperature.
It was stated in 2012 that no truly effective insecticides were available. Insecticides that have historically been found effective include pyrethroids, dichlorvos, and malathion. Resistance to pesticides has increased significantly in recent decades. The carbamate insecticide propoxur is highly toxic to bed bugs, but it has potential toxicity to children exposed to it, and the US Environmental Protection Agency has been reluctant to approve it for indoor use. Boric acid, occasionally applied as a safe indoor insecticide, is not effective against bed bugs because they do not groom.
Bed Bug & Flea Bites Comparison