Bed Bugs Leave Behind Potent Allergen That Lingers Long After They've Been Zapped

We now know that bed bugs produce an allergy and itch-inducing chemical called histamine that can persist in household dust for months after extermination. What a thoughtful hospitality gift. Akos Nagy/Shutterstock

A bed bug infestation is a nightmare. On top of the physical discomfort caused by bites, financial pain is inflicted if you spring for the only proven, yet very expensive, extermination method, which consists of blasting the home with 50°C (122°F) air.

Once the parasitic invaders have been crisply cooked, the ordeal was believed to be over and the phantom skin-crawling sensations could finally subside.


It turns out that’s not quite the case.

Entomologists and a public health expert from North Carolina have discovered that the bugs (Cimex lectularius) leave behind high levels of the allergy-inducing molecule histamine collected in household dust.

According to their study, even after undergoing a heat treatment and passing three blissfully bed bug-free months, previously infected living spaces can contain up to 180 times more histamine than homes that have never hosted the insects.

The data was gathered from 14 infested apartments and 10 un-infested neighboring apartments all in the same complex, and compared to five control apartments located at least 8 kilometers (5 miles) away. 


“The high concentrations, persistence, and proximity to humans during sleep suggest that bed bug-produced histamine may represent an emergent contaminant and pose a serious health risk in the indoor environment,” they wrote in the journal PLOS ONE.

Bed bugs were not known to produce allergens, though their saliva can cause an immune response following a bite, until a 2015 study found that the insects excrete histamine in their feces to chemically communicate with another. We humans also produce histamine, but use it for other purposes. When our body detects the presence of a foreign object or organism, white blood cells release histamine in order to ramp up a defensive immune response. The resulting inflammatory process creates classic allergy symptoms such as watery eyes and a runny nose.

Exposure to airborne, external histamine is dangerous to people with existing allergies or asthma because it ramps up their already overactive immune systems. Skin contact with histamine can result in an itchy, scaly rash known as atopic dermatitis or eczema. And since bed bug histamine lingers in dust – the swirling, easily spreadable bane to cleanliness – inhabitants of once-infested homes and apartments will have a hard time avoiding some type of contact.

(A) a typical bed bug aggregation showing blood-fed and unfed bed bugs and fecal spots that contain histamine (photo credit: Matt Bertone), and (B) a mattress heavily stained by bed bug feces, which contains histamine (photo credit: Mike Waldvogel and Jung W. Kim).

The authors conclude that a new bed bug eradication technique incorporating a combination of insect zapping and histamine neutralization needs to be developed. Until that day, there is one other option...


True to their name, bed bugs prefer to cluster on soft, upholstered surfaces so that they can munch on their reclining hosts at night. Consequently, this is where their histamine-loaded excrement is concentrated. Though we must hope that the residents of these apartments tried to clean their furniture after the infestation was observed, whatever they did was obviously not potent enough to remove the histamine contamination that had infiltrated the fabric.

The logical solution? Burn the furniture and make a fresh start.


  • tag
  • parasitic,

  • bed bugs,

  • allergy,

  • pest,

  • infestation,

  • histamine