Infestations with bedbugs date back to ancient Egypt.¹ The incidence of bedbugs in developed countries decreased in the 1940s because of the availability of more effective pesticides (especially DDT) and improved economic and social conditions.² In the past decade, however, a significant resurgence of bedbug populations has occurred. This is attributed to a combination of factors, including increased pesticide resistance, more frequent travel, lack of public awareness, and inadequate pest control programs.³ In a 2010 survey, 95 percent of more than 500 U.S. pest management companies reported encountering a bedbug infestation during the preceding year, compared with only 25 percent of companies during 2000.⁴ Bedbugs spread actively by migrating from one infested room to another, often through ventilation ducts. They also spread passively, carried in the seams of travelers’ luggage, bedding, or furniture.⁵ Bedbugs do not travel directly on human hosts.⁶

Biology and Habitat

Bedbugs are obligate blood parasites that belong to the insect family Cimicidae. Cimex lectularius and Cimex hemipterus, the two bedbug species that feed primarily on humans, are oval, reddish-brown, flat, and wingless. Adults are typically 4 to 7 mm in length (Figure 1). Nymphs can be as small as 1 mm, and are translucent and lighter in color ^5,7 (Figure 2). Adult females produce 200 to 500 eggs in a typical six- to 12-month life span.^5,8 Bedbugs can withstand temperatures from 44.6°F to 113°F (7°C to 45°C).⁸

To avoid light, bedbugs hide in the seams of mattresses and crevices of bed frames, walls, and furniture during the day.^5,7 They are attracted to human hosts by warmth and carbon dioxide; these hosts generally sleep within 3 to 7 feet (1 to 2 meters) of the bedbugs’ hiding places.^8,9 Feeding usually takes place just before dawn.¹⁰ Bedbug saliva contains several anesthetic, vasodilatory, anticoagulant, and proteolytic compounds that allow the insects to feed undetected for five to 10 minutes. Three of these compounds have been identified as instigators of the subsequent hypersensitivity reactions that may be noticed when the host awakens.^11–14

Clinical Manifestations

Cutaneous reactions to bedbug bites can vary widely and are easily confused with other conditions (Table 1).^15–19 A typical lesion is a 2- to 20-mm, pruritic, erythematous maculopapule with a central hemorrhagic crust or vesicle.^5,8 Macules, papules, wheals (Figure 3), vesicles, bullae, and nodules have all been reported,²⁰ as have asymptomatic lesions with a barely visible punctum as the only evidence of a bite.⁸ Bites vary in number and are preferentially distributed in unclothed areas (e.g., face, neck, extremities). Unlike many other arthropod and insect bites, bedbug bites are rarely located in the popliteal fossae or axillae.²¹ Lesions can be noticeable immediately when waking up or several days later, with the reaction often progressing from delayed to immediate with subsequent exposures^22–26 (Table 2). The classic bedbug rash is referred to as “breakfast, lunch, and dinner” because it commonly presents as several bites in a row or cluster ²⁰ (Figure 4).

Scratching can cause superinfection, leading to impetigo, cellulitis, or folliculitis.^27–32 Reactions typically resolve within one to two weeks without treatment.³² Systemic reactions have been described, including asthma, generalized urticaria, angioedema, iron deficiency anemia, and, very rarely, anaphylaxis.^33–36 Although bedbugs have been suspected to be vectors of more than 40 microorganisms, there is no evidence that they are involved in the transmission of disease.⁵

Psychological Impact

In addition to the physical manifestations of bedbug bites, patients can experience significant psychological distress. The stigma that bedbugs are related to poor hygiene (however inaccurate) can lead to poor self-esteem, avoidance of family and friends, and suspension from work.^37–39 Management of an infestation can be stressful, costly, and disruptive to everyday life. Worry can lead to insomnia, depression, anxiety, and even delusional parasitosis.³⁷

Diagnosis and Management

The diagnosis of a bedbug infestation should be based on the clinical history and appearance of bites. A thorough inspection of sleeping quarters by the patient, a family member, or a pest control expert may demonstrate the telltale signs of an infestation¹⁵ (i.e., specks of blood-tinged insect feces and exoskeleton casts [Figure 5]). With the aid of a magnifying glass, special attention should be given to cracks and crevices of furniture, baseboards, electrical boxes, curtains, carpet, luggage, bed frames and headboards, picture frames, wall hangings, mattress and box spring seams, peeling wall paper, clothes, and linens.³⁷ Live bedbugs can sometimes be caught by turning on a flashlight just before dawn, when bedbugs are most active, larger in appearance, and slower to scatter because of recent feeding.⁴⁰

Once an infestation is confirmed, an integrated pest management strategy should be employed. Promoted by the Environmental Protection Agency (EPA) and the Centers for Disease Control and Prevention, an integrated pest management strategy is a multi-faceted, comprehensive strategy that relies on knowledge of bedbug biology and habits, and the most up-to-date pest control methods.³ An integrated pest management strategy minimizes economic, environmental, and health hazards, and is most effective for small bedbug populations.

In most infestations, consultation with a professional exterminator is advised because elimination is more likely to be effective if multiple pest management methods are used. These include monitoring devices, canine detection, clutter removal, vacuuming, heat or cold treatment, sealing cracks and crevices, and judicious use of nonchemical and chemical pesticides. Monitoring devices include moat-like devices (e.g., Climbup Insect Interceptor) that trap bedbugs ascending and descending furniture legs, and emitting devices that use carbon dioxide, heat, and/or chemicals (e.g., Nightwatch monitor) that attract and trap bedbugs. Specially trained dogs are reported to detect bedbugs with 97 percent accuracy and are able to differentiate live bedbugs and viable eggs from debris remaining from previous infestations.⁴¹ Vacuuming is a highly effective method for removing bedbugs, but not eggs because these adhere to surfaces.⁴² High-efficiency particulate air filters eliminate bedbug allergens and debris.⁴² Nonchemical treatments include petroleum jelly (which can be applied to legs of furniture to prevent bedbugs from ascending), heating, and freezing (see Table 3⁶ for effective killing temperatures).

Many chemical pesticides are available, with more than 300 registered by the EPA. Pesticides should be applied to walls, floors, cracks in furniture, and seams and buttons of mattresses.²¹ The EPA’s Bed Bug Products search tool (Web site: http://cfpub.epa.gov/oppref/bedbug/) allows users to search by product name, company, EPA registration number, location of intended use, and pesticide type. The National Pesticide Information Center (Web site: http://npic.orst.edu/; telephone: 800-858-7378) is another useful resource. Silica gel dusts are a safer alternative to traditional pesticides, because they are less concentrated and less toxic.²¹ Plastic mattress and pillow encasements can help trap bedbugs and restrict spread.⁴² Regardless of the integrated pest management strategy used, a follow-up inspection 10 to 21 days after extermination is advised to detect and manage a persistent infestation.⁴²

Management of an infestation can be costly because it often requires multiple treatments by pest control experts. The National Pest Management Association quotes an average price of $200 to $500 per treatment session.⁴³

Treatment of Bites

Bedbug bite reactions are self-limited and typically resolve within one to two weeks without intervention.¹⁵ There is no evidence that any treatment alters the natural history of bedbug dermatitis.⁸ If pruritus is present, nonprescription topical antipruritic preparations containing the active ingredient doxepin, or intermediate potency corticosteroids may be beneficial. Mupirocin (Bactroban) and/or systemic antibiotics should be considered in the treatment of superinfected bites.⁸

Prevention

Avoidance is the best means of preventing bedbug infestation.⁸ While traveling, sleeping quarters and bedding should be closely inspected for signs of bedbugs. Suitcases should be placed on metal racks away from walls and furniture. Frequent travelers might consider obtaining a portable heating unit for luggage and clothing (e.g., Packtite) as an additional precaution. Items at yard sales and secondhand stores should also be carefully examined before purchase.⁸ All potentially infested items should be sorted and sealed in plastic bags and removed only when ready to be disinfested (see Table 3⁶ for instructions regarding effective care of infested items). Wearing long-sleeved nightclothes can minimize exposed skin, and although insect repellants have not been shown to be reliably effective, oil of lemon eucalyptus or diethyltoluamide (DEET) might help deter bites.^44,45

Data Sources: A PubMed search was completed in Clinical Queries using the key terms bedbug, rash, bites, and infestation. The search included meta-analyses, randomized controlled trials, clinical trials, case reports, and reviews. We also searched the online databases of the Environmental Protection Agency, Centers for Disease Control and Prevention, and Jefferson Clinical Images. Lastly, we used Essential Evidence Plus. Search dates: February through June 2011.