What are the clinical manifestations of bites from bed bugs and how are they treated?

Updated: Jun 21, 2018
  • Author: Boyd (Bo) D Burns, DO, FACEP, FAAEM; Chief Editor: Joe Alcock, MD, MS  more...
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Answer

Bed bugs (Cimex lectularius) were essentially a nonissue in the 1970s and 1980s, owing to effective insecticides like DDT. Increasing resistance and limitation of those insecticides have caused bed bug infestations to become an almost ubiquitous issue in the United States and other developed countries. A multitude of studies have shown an alarming increase of bed bug infestations over the last several years. [4] Bed bugs tuck away in clothing and shoes or easily migrate through walls of shared housing. Bed bugs can usually be found initially in the inner workings or the base of box springs but also like to hide in mattresses, under baseboards, along crevices in the walls, in vents, and even behind picture frames. [4] Infestations can be identified by fecal spotting (seen below).

Fecal staining from bed bugs in the crevice of a m Fecal staining from bed bugs in the crevice of a mattress. © 2014 Australian Family Physician. Reproduced with permission from The Royal Australian College of General Practitioners (RACGP), published in Doggett SL, Russell R. Bed bugs - What the GP needs to know. Aust Fam Physician. Nov 2009;38(11):880-4.

Bed bugs are flightless and are ovoid and flattened in shape. They are photophobic and all are obligatory blood feeders on vertebrates, with their preferred host being humans. Bed bugs have 5 juvenile stages, which are pictured below, along with the adult male and female forms. [5]

When bitten, cutaneous reactions (as seen below) usually appear within several hours of the bite, and patients usually notice these reactions the morning after having been bitten.

Various stages of the bed bug life cycle. © 2014 A Various stages of the bed bug life cycle. © 2014 Australian Family Physician. Reproduced with permission from The Royal Australian College of General Practitioners (RACGP), published in Doggett SL, Russell R. Bed bugs - What the GP needs to know. Aust Fam Physician. Nov 2009;38(11):880-4.

The reactions themselves are myriad in character and vary widely between individuals, with some patients showing no reaction at all. [5] Distinguishing a bed bug lesion from those caused by other insects is difficult; however, the classic "bed bug wheal" is an extremely pruritic papular urticaria and may be as large as 2-6 cm. For the clinician, the history of bug or insect bites may be unknown to the patient and this should always be in the differential, especially in the setting of a new travel location for sleep or worsening lesions just after sleep. These lesions can be in linear or bunched configurations and are usually found on exposed skin. [5] Other cutaneous reactions can be more pronounced, with anything from bullous, hemorrhagic reaction [6] to a more targetoid appearance. [7] Anaphylaxis from bed bug bites is also possible, necessitating prompt recognition and treatment.

See the image below.

Typical bed bug rash. Image courtesy of Wikimedia Typical bed bug rash. Image courtesy of Wikimedia Commons.

Treatment of cutaneous reactions does not differ from the general treatment for other insect envenomations discussed later. Although difficult, identifying cutaneous lesions from bed bugs versus other causes is important to prevent misdiagnosis and subsequent unneeded treatments and procedures (eg, scabicides, skin biopsies). Bed bugs are not known to transmit any human diseases. [4] Eradication of bed bug harborages is expensive, specialized, and challenging to say the least. It should only be undertaken by professionals.


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