When bed bugs bite

,

Applied Evidence

When bed bugs bite

J Fam Pract. 2012 July;61(7):384-388

By

Mark K. Huntington, MD, PhD

Treating bed bug bites is straightforward; helping patients control and even prevent future infestations is another matter. Here’s how you can help.

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References

1. Usinger RI. Monograph of the Cimicidae (Hemiptera-Heteroptera). Vol VII. College Park, Md: Entomological Society of America; 1966.

2. Berg R. Bed bugs: the pesticide dilemma. J Environ Health. 2010;72:32-35.

3. Snetsinger R. Bed bugs & other bugs. In: Hedges S, ed. Mallis’ Handbook of Pest Control. 8th ed. Cleveland, Ohio: GIE Media; 1997:392–424.

4. Eddy C, Jones SC. Bed bugs, public health, and social justice: part 1, a call to action. J Environ Health. 2011;73:8-14.

5. Hurst S, Humphreys M. Bedbugs: not back by popular demand. Dimens Crit Care Nurs. 2011;30:94-96.

6. Anderson A. The decade of bedbugs and fear. Environ Health Insights. 2011;5:53-54.

7. America’s 10 most infested cities. The Daily Beast; August 24, 2010. Available at: http://www.thedailybeast.com/articles/2010/08/24/bedbug-outbreak-which-cities-are-most-infested.html. Accessed August 28, 2011.

8. Hosokawa T, Koga R, Kikuchi Y, et al. Wolbachia as a bacteriocyte-associated nutritional mutualist. Proc Natl Acad Sci U S A. 2010;107:769-774.

9. Sakamoto JM, Rasgon JL. Geographic distribution of Wolbachia infections in Cimex lectularius (Heteroptera: Cimicidae). J Med Entomol. 2006;43:696-700.

10. Abou Gamra EM, el Shayed FA, Morsy TA, et al. The relation between Cimex lectularius antigen and bronchial asthma in Egypt. J Egypt Soc Parasitol. 1991;21:735-746.

11. Delaunay P, Blanc V, Del Giudice P, et al. Bedbugs and infectious diseases. Clin Infect Dis. 2011;52:200-210.

12. Pritchard MJ, Hwang SW. Cases: severe anemia from bedbugs. CMAJ. 2009;181:287-288.

13. Delaunay P. Cimex lectularius or bed bug: vector of infectious agents and pathogenic role. Available at: http://www.clinicaltrials.gov. Identifier: NCT01089465. Accessed November 29, 2011.

14. Rieder E, Hamalian G, Ying P. Psychiatric implications of bedbugs. Presented at: 164th Annual Meeting of the American Psychiatric Association; May 14-18, 2011; Honolulu, Hawaii. Abstract NR01-51.

15. Roos TC, Alam M, Roos S, et al. Pharmacotherapy of ectoparasitic infections. Drugs. 2001;61:1067-1088.

16. Goddard J, deShazo R. Bed bugs (Cimex lectularius) and clinical consequences of their bites. JAMA. 2009;301:1358-1366.

17. Centers for Disease Control and Prevention and Environmental Protection Agency. Joint statement on bed bug control in the United States from the U.S. Centers for Disease Control and Prevention (CDC) and the U.S. Environmental Protection Agency (EPA). Atlanta, Ga: US Department of Health and Human Services; 2010. Available at: http://www.cdc.gov/nceh/ehs/Publications/Bed_Bugs_CDC-EPA_Statement.htm. Accessed June 15, 2012.

18. Axtell RC, Arends JJ. Ecology and management of arthropod pests of poultry. Annu Rev Entomol. 1990;35:101-126.

19. Moore DJ, Miller DM. Field evaluations of insecticide treatment regimens for control of the common bed bug, Cimex lectularius (L.). Pest Manag Sci. 2009;65:332-338.

20. CDC. Acute illnesses associated with insecticides used to control bed bugs—seven states, 2003–2010. MMWR Morb Mortal Wkly Rep. 2011;60:1269-1274.

21. Tawatsin A, Thavara U, Chompoosri J, et al. Insecticide resistance in bedbugs in Thailand and laboratory evaluation of insecticides for the control of Cimex hemipterus and Cimex lectularius (Hemiptera: Cimicidae). J Med Entomol. 2011;48:1023-1030.

22. Benoit JB, Lopez-Martinez G, Teets NM, et al. Responses of the bed bug, Cimex lectularius, to temperature extremes and dehydration: levels of tolerance, rapid cold hardening and expression of heat shock proteins. Med Vet Entomol. 2009;23:418-425.

23. Benoit JB, Phillips SA, Croxall TJ, et al. Addition of alarm pheromone components improves the effectiveness of desiccant dusts against Cimex lectularius. J Med Entomol. 2009;46:572-579.

24. Heukelbach J, Feldmeier H. Scabies. Lancet. 2006;367:1767-1774.

25. Fox LM. Ivermectin: uses and impact 20 years on. Curr Opin Infect Dis. 2006;19:588-593.

26. Foucault C, Ranque S, Badiaga S, et al. Oral ivermectin in the treatment of body lice. J Infect Dis. 2006;193:474-476.

27. Dias JC, Schofield CJ, Machado EM, et al. Ticks, ivermectin, and experimental Chagas disease. Mem Inst Oswaldo Cruz. 2005;100:829-832.

28. Kobylinski KC, Sylla M, Chapman PL, et al. Ivermectin mass drug administration to humans disrupts malaria parasite transmission in Senegalese villages. Am J Trop Med Hyg. 2011;85:3-5.

29. Ostlind DA, Cifelli S, Conroy JA, etal. A novel Cimex lectularius– rodent assay for the detection of systemic ectoparasiticide activity. Southwest Entomol. 2001;26:181-186.

30. Tamarozzi F, Halliday A, Gentil K, et al. Onchocerciasis: the role of Wolbachia bacterial endosymbionts in parasite biology, disease pathogenesis, and treatment. Clin Microbiol Rev. 2011;24:459-468.

31. Kells SA, Hahn J. Prevention and control of bed bugs in residences. Available at: http://www.extension.umn.edu/distribution/housingandclothing/dk1022.html. Accessed November 29, 2011.

32. Got bedbugs? Your hotel might! Available at: http://www.smartertravel.com/travel-advice/avoiding-bedbugs-every-traveler-nightmare.html?id=4726511. Published April 25, 2010. Accessed November 29, 2011.

33. US Environmental Protection Agency. Bed bug information. Available at: http://www.epa.gov/bedbugs/index.html. Accessed November 29, 2011.

PRACTICE RECOMMENDATIONS

• Provide symptomatic relief for bed bug bites with antihistamines or corticosteroids. C

• Advise patients experiencing an infestation to consider the CDC’s recommended integrated pest management program (eg, heat treatment, vacuuming, nonchemical pesticides) to increase the likelihood of successful extermination. C

Strength of recommendation (SOR)

A Good-quality patient-oriented evidence
B Inconsistent or limited-quality patient-oriented evidence
C Consensus, usual practice, opinion, disease-oriented evidence, case series

Bed bugs, Cimex spp, are a re-emerging public health problem in the United States. First recorded by the ancient Greeks,¹ bed bugs have plagued societies for centuries. In the United States, infestations peaked in intensity in the 1920s and 1930s, then were largely eliminated as a significant concern after World War II, thanks to synthetic, residual pesticides.² By the mid-1990s, bed bugs were so uncommon that specimens could not be obtained for medical education purposes.³

That has all changed.

Although commonly perceived as disproportionately affecting the underprivileged,⁴ bed bugs are equal-opportunity pests, infesting the most posh hotels, retailers, and theaters.^5,6 According to one news report summarizing data from a national pest control firm, US cities with the highest infestation rates are, in descending order: Cincinnati, Columbus, Chicago, Denver, Detroit, Washington DC, New York, Philadelphia, Dayton, and Baltimore.⁷ Although bed bugs are not known to transmit infectious diseases, they are responsible for significant dermatitis, allergic reactions, and psychological distress.

Bed bug biology and behavior

The bed bug life cycle has 7 stages. All but the egg stage require blood meals before the arthropod can molt to the next stage. Bed bugs are attracted to their hosts by body heat and exhaled carbon dioxide, and they feed only through the skin. This makes baiting and trapping challenging, although it’s a common extermination strategy for other domestic pests. Also, unlike cockroaches, flies, or other pests, bed bug infestations are not associated with hygienic deficiencies. Improved housekeeping does not significantly affect their populations; bed bugs feed on household inhabitants, not their spilled or improperly stored food. However, clutter does increase their chances of finding refuge.

Interestingly, researchers recently discovered that bed bugs are themselves hosts to the endosymbiotic bacterium, Wolbachia.^8,9 This genus is found in many invertebrates and appears to be essential for normal bed bug fertility and reproduction. Targeting the bacteria may inhibit the ability of bed bugs to breed—something we’ll discuss a bit later.

Clinical assessment

Patients with bed bug bites complain about intensely pruritic lesions. These are typically erythematous and indurated and may be hemorrhagic. The pattern of bites is often linear, and 3 bites in a row are common, sometimes referred to as “breakfast, lunch, and dinner.” Patients typically have no recollection of being bitten, as bed bugs feed on sleeping hosts, and their bite is usually painless.

Clues to bed bugs as the source. Scabies mites also cause linear pruritic lesions, but bed bug lesions differ in appearance and distribution. Scabies lesions are subtle, appearing as burrows and excoriations, in contrast to the more prominent erythematous papule seen with bed bugs and other arthropod bites. Scabies tend to occur in skin folds, finger webbing, genitals, and areas where clothing is tight, such as beltlines. In contrast, bed bugs tend to attack easily accessible, exposed areas. Areas covered with loose clothing are less affected, and areas covered by tight clothing are essentially spared. Multiple members of the household are often affected.

Flea bite? Bed bug bites may be virtually indistinguishable from those of other arthropods such as fleas, spiders, or mosquitoes. While the linear 3-bite pattern may suggest bed bug exposure, it is not pathognomonic. Capturing the arthropod or finding evidence of infestation (discussed in a bit) is needed to confirm a bed bug as the source of the bite.

The etiology of pruritic papules is broad. Besides arthropod bites, include conditions such as papular eczema, papular pruritic eruption, and eosinophilic folliculitis in the differential diagnosis.

Potential for complications
As with any break in the skin, secondary infection is a risk, although it is rarely a complication of the bite. If infection occurs, it is more likely due to scratching. Bed bug bites are allergenic, and they have also been implicated in asthma exacerbations and even anaphylaxis.^10,11 In severe infestations, anemia from the extensive blood-meals can occur.¹²

Experimental studies have found that >45 human pathogens—ranging from viruses to methicillin-resistant Staphylococcus aureus to helminths—can survive ingestion by bed bugs, but none have shown pathogens to be transmitted to humans by bed bugs.¹¹ Fortunately, bed bugs do not appear to be competent as vectors, although prospective studies are ongoing.¹³ In addition to allergic manifestations, bed bug bites have been associated with significant, even incapacitating, psychiatric problems such as anxiety, obsession, and depression to the point of suicide.¹⁴