bed bug bed bug bed bugs are insects from the genus cimex that feed on 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 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. their bites are not known to transmit any infectious disease. complications may rarely include areas of dead skin or vasculitis. bed bugsother namescimicosis, bed bug bites, bedbugs, bed bug infestationan adult bed bug (cimex lectularius) with the typical flattened oval shapespecialtyfamily medicine, dermatologysymptomsnone to prominent blisters, itchinessusual onsetminutes to days after the bitecausescimex (primarily cimex lectularius and cimex hemipterus)risk factorstravel, second-hand furnishingsdiagnostic methodbased on finding bed bugs and symptomsdifferential diagnosisallergic reaction, scabies, dermatitis herpetiformistreatmentsymptomatic, bed bug eradicationmedicationantihistamines, corticosteroidsfrequencyrelatively common 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 70 days 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. 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. effects on humans bedbug bites bedbug bites bed bugs infest dwellings and bite people, causing irritation and sometimes other issues. there is no evidence that bed bugs transmit infectious diseases even though they appear physically capable of carrying pathogens and this possibility has been investigated. bites the most common skin findings associated with bed bug bites are pruritic, maculopapular, erythematous lesions. each lesion is about 2–5 mm but may be as large as 2 cm in diameter and there may or may not be the presence of a central punctum. bites are usually present on areas of exposed skin, especially exposed areas not covered by sheets or blankets, such as arms, legs, feet, face or neck. 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 lesions due to bites may become secondarily infected due to scratching but systemic effects from bed bug bites are very rare. 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 brisker after multiple bites due to possible sensitization to the salivary proteins of the bed bug. numerous bites may lead to a red rash or hives. bedbug bites may cause other symptoms and health issues. serious allergic reactions including anaphylaxis from the injection of serum and other non-specific proteins have been documented, though rarely. as each bite takes a tiny amount of blood, chronic or severe infestation may lead to anemia. scratching bites may lead to bacterial skin infection. systemic poisoning may occur if the bites are numerous. the bite itself may be painful thus resulting in poor sleep and worse work performance. bed bugs can feed on warm-blooded animals other than humans, such as pets. the signs left by the bites are the same as in the case of people and cause identical symptoms (skin irritation, scratching etc.). bed bugs can infest poultry sheds and cause anemia and a decrease in egg production in hens. treatment treatment of bed bug 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. other effects of infestation it is possible that exposure to bed bugs may trigger an asthma attack via the effects of airborne allergens, although evidence of this association is limited. 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. description an adult bed bug is about 4 to 5 mm long. bed bug infestations are primarily the result of two species of insects from genus cimex: cimex lectularius (the common bed bug) and cimex hemipterus (the tropical bed bug). these insects feed exclusively on blood and, at any stage of development, may survive up to 70 days without feeding. adult cimex are light brown to reddish-brown, flat, oval, and have no hind wings. the front wings are vestigial and reduced to pad-like structures. adults grow to 4–5 mm (0.16–0.20 in) long and 1.5–3 mm (0.059–0.118 in) wide. female common bed bugs can lay 1–10 eggs per day and 200–500 eggs in their lifetime, whereas female tropical bed bugs can lay about 50 eggs in their lifetime . bed bugs have five immature nymph life stages and a final sexually mature adult stage. bed bugs need at least one blood meal in order to advance to the next stage of development. they shed their skins through ecdysis at each stage, discarding their outer exoskeleton. newly hatched nymphs are translucent, lighter in color, and become browner as they moult and reach maturity. bed bugs may be mistaken for other insects, such as booklice, small cockroaches, or carpet beetles; however, when warm and active, their movements are more ant-like, and like most other true bugs, they emit a characteristic disagreeable odor when crushed. bed bugs are obligatory bloodsuckers. they have mouth parts that saw through the skin and inject saliva with anticoagulants and painkillers. sensitivity of humans varies from extreme allergic reaction to no reaction at all (about 20%). the bite usually produces a swelling with no red spot, but when many bugs feed on a small area, reddish spots may appear after the swelling subsides. bedbugs prefer exposed skin, preferably the face, neck, and arms of a sleeping person. bed bugs are attracted to their hosts primarily by carbon dioxide, secondarily by warmth, and also by certain chemicals. there is strong evidence that bed bugs can respond and orient towards human odors, independently of all other host cues. cimex lectularius feeds only every five to seven days, which suggests that it does not spend the majority of its life searching for a host. when a bed bug is starved, it leaves its shelter and searches for a host. it returns to its shelter after successful feeding or if it encounters exposure to light. cimex lectularius aggregate under all life stages and mating conditions. bed bugs may choose to aggregate because of predation, resistance to desiccation, and more opportunities to find a mate. airborne pheromones are responsible for aggregations. infestation 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 into 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. detection knowing that symptoms are caused by bedbug bites rather than other causes requires seeking and finding the insect in the sleeping environment, as symptoms are not specific to bedbug bites. bites by other arthropods, even the linear pattern of bites known colloquially as "breakfast, lunch and dinner bites", cause similar symptoms. bed bugs can occur singly, but tend to congregate once established. although strictly parasitic, they spend only a tiny fraction of their lives physically attached to hosts. once a bed bug finishes feeding, it follows a chemical trail to return to a nearby harborage, commonly in or near beds or couches, where they live in clusters of adults, juveniles, and eggs. these places may include luggage, vehicle interiors, furniture, bedside clutter—even inside electrical sockets or laptop computers. bed bugs may also lodge near animals that have nested within a dwelling, such as bats, birds, or rodents. they can also survive by feeding on domestic cats and dogs, though humans are the preferred host of c. lectularius. a severe bedbug infestation can be detected by their characteristic pungent sweet smell, which has been described as like 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. bedbug detectors, often referred to as "monitors", "traps" or "interceptors", use the lactic acid or carbon dioxide associated with the presence of a human body, or pheromones, to attract and trap bugs in a container. bedbug detectors can confirm an infestation, but do not trap enough for eradication. eggs and two adults found inside a dresser fecal spot bed bug on carpet differential detection other conditions which produce symptoms similar to bedbug bites include scabies, gamasoidosis, allergic reactions, mosquito bites, spider bites, chicken pox and bacterial skin infections. prevention to prevent bringing home bed bugs from outside the home, people are advised to take precautions after visiting an infested site or traveling on means of transport that may be infested; precautions 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. clothes should be hung up or left in the suitcase rather than left on the floor. additional preventative measures include sealing cracks and crevices (where bed bugs often hide), inspecting furniture, and decontaminating clothes and luggage upon returning home. the founder of a company dedicated to bedbug extermination said that 5% of hotel rooms he booked 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. close all wall openings or gaps; bed bugs tend to hide in dark places such as cracks in walls. second-hand furniture may harbour bedbugs. management avoiding repeated bites can be difficult since it usually requires eradicating bed bugs from a home or workplace; eradication is most effective using non-chemical control methods. non-chemical control methods include vacuuming carpet and furniture (often with scraping) into a disposable bag which is then sealed into a plastic bag to prevent re-infestation. other methods include removing textile materials from an area and washing them in hot