Faculty peer reviewed
A 46 year-old Asian female presented with recurrent pruritic erythematous papules in a partially linear pattern over her forearms, face, and trunk. Each papule measured about 3/4 inch in diameter. The eruption first appeared two to three weeks ago and simultaneously appeared over these areas. She denies using any new skin products or taking any new medication. Travel history is positive for a recent trip to Los Angeles. Bedbugs were suspected and the patient was prescribed oral diphenhydramine and topical fluocinonide. She returned one week later, despite healing of the old lesions. A few more papules have appeared over her forearms.
Cimex lectularius, commonly known as the bedbug, had been a pest of yesteryear, until recently. Reports of bedbug infestation in hotels began to emerge at the turn of the millennium. Soon after, bedbugs spread like wildfire across major cities in the country, infesting apartments, private houses, college dormitories, nursing homes, and even hospitals. New York City was no exception; in 2008, the city’s 311 hotline received almost 10,000 bedbug complaints, a 34% increase from the year before.  New York has a bedbug epidemic, and there is no relief in sight.
Host reactions to bedbug bites are widely variable. Most people do not have a reaction; others may develop pruritic erythematous papules, or local urticaria with wheals or welts. Bullous skin lesions and systemic anaphylactic reactions have also been reported but are rare. The lesions may be evident upon awakening or may appear a day or two later. They are the result of host hypersensitivity against foreign antigens in bedbug saliva; the bite itself is harmless. The lesions are usually pruritic, and they can become superinfected after intense scratching. Secondary skin lesions such as cellulitis or folliculitis may also develop. The diagnosis is not always clear, especially without a suggestive history. The eruption has been mistaken for scabies, allergic contact dermatitis, dermatitis herpetiformis, and even chicken pox. [7,8] Lesions in a linear or clustered pattern should raise the suspicion of bedbug bites, although other insect bites can present in similar manner. A detailed history exploring possible sources of exposure is helpful. The most common lesions are pruritic papules, which spontaneously regress over one to two weeks, but often leave behind the telltale sign of postinflammatory hyperpigmentation.
Treatment provides symptomatic relief only. The most commonly used agents are oral antihistamines and topical medium-strength corticosteroids. Severe reactions such as bullous skin lesions may require oral corticosteroids. Those with secondary infections should be treated with topical or oral antibiotics. Systemic or anaphylactic reactions to bedbug bites are treated with intramuscular epinephrine, oral antihistamines, and corticosteroids. Insect repellents containing N,N-diethyl-meta-toluamide (DEET), and oil of lemon eucalyptus may help ward off some attacks. Although the majority of patients improve with symptomatic treatment, a complete cure from bedbug bites requires total extermination of the pest from the household.
There is no evidence that bed bugs serve as vectors for infectious agents. Research has shown that hepatitis B viral DNA (HBV DNA) and surface antigen (HBsAg) can persist for weeks in bedbugs, although there is no evidence of viral replication in the insect. HBV DNA has also been found in bedbug excrement, which raises concern about transmission of HBV via deposition of infected waste matter after feeding. However, an epidemiologic study found bedbugs an unlikely factor in the spread of hepatitis B in a Gambian pediatric population. Human immunodeficiency virus (HIV) is also detected in bedbugs after experimental feeding; again, the virus does not replicate in the insect, and the bedbug’s ability to transmit HIV has not been demonstrated under experimental conditions.
C. lectularius are flightless nocturnal insects that solely feed on the blood of humans, other mammals, bats, and birds. Adult insects average about 5 mm in length. They are flat, oval and reddish brown, but may become elongated, engorged, and dark red after a blood meal. Bedbugs feed on their reclining hosts at night. They are attracted to their hosts by warmth, carbon dioxide, and kairomones within a 1.5-meter radius.6 Each blood meal takes about 10 minutes, after which they quickly flee from the hosts and return to their hiding places, which can be any nook or cranny in and around the bed. Bedbug harborages have been found in furniture, mattresses, and box springs, as well as behind loose wallpaper, headboards, floorboards, and even electric outlets and picture frames.11 Because bedbugs hide during the day, initial signs of infestation may not be visible to the victim. The insects are better caught when surprised by a flashlight at night. 2,7 Bedbugs also leave dark specks of waste matter on bed linen.[7,11]
Extermination of bedbugs is extremely difficult. Complete eradication requires meticulous and multiple applications of insecticide. A major concern is resistance to pyrethroids, the most commonly used agents. Organophosphate and carbamate insecticides are effective, but their use indoors is banned for safety reasons. Non-insecticide means of control may be used. Bedbugs are killed at temperatures above 45C (113F);11 bedding and clothes should be washed and dried at the hottest settings. Other means to control the infestation include encasing the mattress and boxspring, routinely using the vacuum cleaner, chalking the baseboard, and covering all crevices in the floor. Techniques to contain bedbugs may fail because the insects are resilient; they may live up to one year without a blood meal. For some, hiring a professional exterminator and discarding the affected furniture are expensive but inevitable last resorts.
Because bedbug extermination is so difficult, prevention is key. People should refrain from reusing second-hand furniture and mattresses, which may be infested. Bedbugs can latch onto luggage during travel; travelers should vacuum and clean their suitcases thoroughly after returning from their trips. Although bedbug infestations are not associated with unsanitary conditions, households should eliminate clutter, which offers places for bedbugs to establish harborages. People with a bedbug problem should seek help right away. Bedbug infestation is associated with considerable psychological distress in most victims. Many feel shame and may be reluctant to speak up for fear of eviction from their apartments or ostracism by their peers. This worsens the situation and may promote the spread of bedbugs to neighboring rooms or apartments.
Bedbugs are a growing public health issue. Although there is no evidence that they can transmit infectious diseases, they cause considerable physical discomfort and psychological anguish. As bedbug infestations become more prevalent, the medical community needs to be vigilant about this problem. Bedbug infestation should be a part of the differential diagnosis for patients who present with recurrent pruritic skin eruptions. Because healthcare providers are often the first persons from whom bedbug victims seek help, they are instrumental in providing education, reassurance, and treatment.
Jia Huang is a 3rd year medical student at NYU Medical Center.
Peer reviewed by Miriam Pomeranz MD
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