Bed Bug

Aka: Bed Bug, Bed Bug Bite, Cimex lectularius, Cimex hemipterus

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II. Epidemiology

  1. Bed Bugs declined after 1940 due to use of Pesticides (e.g. DDT)
  2. Bed Bug resurgence after 2000 due to international travel, Pesticide resistance

III. Pathophysiology

  1. Images
    1. bedbug.jpg
  2. Obligate blood Parasite in the Cimicidae family
  3. Two species primarily affecting humans
    1. Cimex lectularius
    2. Cimex hemipterus
  4. Life stages (6-12 month lifespan)
    1. Egg
      1. Adult females produce up to 500 eggs in their year long life span
      2. Adheres to surfaces via a glue-like substance
    2. Nymph (5 distinct stages)
      1. Size of sesame seed (1 mm)
      2. Lighter color and translucent
    3. Adult
      1. Size of lentil (4-7 mm long)
      2. Red-brown flat, oval and wingless
  5. Feeding
    1. Bed Bugs avoid light and remain hidden in mattress or furniture during day
    2. Bed Bugs are attracted to carbon dioxide (typically from people sleeping with 1-2 meters of their hiding place)
    3. Bed Bugs typically feed immediately before dawn
      1. Feed for 5-10 minutes
      2. Saliva contains Anesthetic that prevents host from initially recognizing the bite
      3. Hypersensitivity Reaction follows on host awakening
  6. Hardiness
    1. Can withstand not eating for up to one year
    2. Can withstand fogging devices and most Pesticides
    3. Bed Bugs can survive Temperatures between 44 and 113 F (7 to 45 C)

IV. Background

  1. Transmission into home
    1. Travel items (Luggage, Clothing, Shoes)
    2. Conduits (e.g. electrical wiring, ventilation system between rooms or attached apartments)
  2. Common Sites in home (Bed Bugs avoid light)
    1. Mattress or box spring seams and underside
    2. Wheel Chairs

V. Symptoms

  1. Moderate to intense Pruritus

VI. Signs: Bite Reaction

  1. Reaction is allergic and occurs in 70% of patients
  2. Characteristics
    1. Initial reactions are Red Papules with centra puncta in line or group
    2. Later reactions are variable lesion types (e.g. Papules, wheals, vessicles)
  3. Bites form linear pattern
    1. Often form line of 3 bite sites (breakfast, lunch and dinner)
  4. Distribution of bite sites on exposed skin
    1. Face and and neck
    2. Arms and legs
    3. Back
    4. Spares popliteal fossa and axilla
  5. Course
    1. Resolves spontaneously in 1-2 weeks

VII. Differential Diagnosis

  1. Bedbugs
    1. Pruritic row of Papules or wheals on exposed skin (excoriations may alter appearance)
  2. Fleas
    1. Irregularly grouped wheals each with central bite site on loosely covered skin (e.g. waist band)
  3. Scabies
    1. Pruritic burrows especially in intertriginous areas (e.g. web space)
  4. Tick Bite
    1. Red Papule with variable Pruritus often in areas of Hair Growth or in skin creases
  5. Mosquito Bite
    1. Small pruritic wheals randomly scattered over exposed skin
  6. Spider Bite
    1. Isolated, single lesion typically on thin skin covered with clothing

VIII. Management: Identification and elimination of Bed Bugs

  1. Examine furniture, bedding, curtains, luggage seams with magnifying glass
    1. Observe for blood tinged tiny feces and exoskeleton casts
    2. Consider searching just before dawn with a flashlight (when Bed Bugs are most active)
  2. Identify infestations early
    1. Easier to eradicate at an earlier stage (prior to infestation of wiring)
  3. Travelers
    1. Inspect hotel room well on arrival and throughout stay
    2. Place luggage on rack well above ground
    3. Consider traveling with portable heating unit (Packtite) to treat luggage
  4. Quarentine items suspected of infestation
    1. Place items in sealable plastic bags
    2. Consider plastic encasements for mattress and pillows
    3. Vaseline applied to furniture legs prevents Bed Bugs from climbing
  5. Detection and monitoring
    1. Climbup Insect Interceptor (moat device)
    2. Nightwatch Monitor (emits carbon dioxide from a trap)
    3. Consider dogs that have been trained to specifically smell for Bed Bugs in hospitals, Nursing Homes
  6. Eradicate Bed Bugs
    1. Consult with local pest control experts (exterminators)
      1. Variety of Pesticides used (silica gel dusts are safer options)
      2. Typically requires multiple treatments (spaced 2-3 weeks apart)
    2. Methods
      1. Heat to over 120 F for at least 30 minutes to kill Bed Bugs
      2. Cool at <23 F (-5 C) for 5 days or -15 F (-26 C) instantly
      3. Vacuuming removes Bed Bugs (but not eggs)
      4. Consider hand held steamer in commercial settings

IX. Management: Bed Bug Bites

  1. See Pruritus Management
  2. No specific treatment is available

X. Complications

  1. Related to scractching pruritic lesions
  2. Cellulitis
  3. Impetigo
  4. Theoretical vector for disease transmission (but no case reports of this)
    1. Can carry MRSA, VRE and other Bacteria, as well as viruses and fungi

XI. Resources

  1. EPA Bed Bug Product Search
    1. http://cfpub.epa.gov/oppref/bedbug/
  2. National Pesticide Information Center
    1. http://npic.orst.edu/
  3. University of Minnesota
    1. http://www1.extension.umn.edu/garden/insects/find/bed-bugs-and-traveling/

XII. References

  1. Kells (2006) Guide for travelers to prevent bringing home Bed Bugs, UMN Extension
  2. Marco (2013) Crit Dec in Emerg Med 27(1): 2-7
  3. Weingart and Jones in Majoewsky 2012) EM:RAP 12(4): 2-3
  4. Heymann (2009) J Am Acad Dermatol 60(3): 482-3 [PubMed]
  5. Studdiford (2012) Am Fam Physician 86(7): 653-8 [PubMed]

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