Mysterious bites: Here’s what you should do


February 16, 2023



Besides the affected individuals, relatives and those who become involved, nothing can bother a pest management professional (PMP) as much as mysterious “bites.” Unfortunately, the records of people diagnosed with “invisible bugs” on the rise.

From a technical perspective, people who believe that they are infested with bugs are experiencing delusory parasitosis, or DP (Waldron, 1962). Those who believe that their homes or belongings are infested are exhibiting cleptoparasitosis (Grace and Wood, 1987).

To professionally deal with mysterious “bites,” you as the PMP should perform a thorough inspection first and avoid theories. You are neither a physician nor a psychiatrist (well, unless you are one of the few in our industry who are!). Therefore, as a PMP, you should be focusing on inspecting the sites of the infested area, not on the affected person. During the inspection, look for tiny biting pests, such as bird mites or rodent mites. You may need to inspect the attic or crawlspace to look for abandoned nests. Most bird mites attack living places when their primary hosts vacate their nests. While inspecting, search for evidence of common biting arthropods, such as mosquitoes, fleas, bed bugs, or ticks (Mellanby, 1946; Hudson, et al., 1960; Sansom et al., 1992; Wikel, 1996).

Early infestations of these pests can be hard to locate. Consequently, arrange to leave some glue traps in suspected areas to monitor for at least a week. Personal pests for humans, such as scabies and lice can be the culprits. If that’s the case, let the customer know you as a PMP cannot do anything about the problem and that affected individuals should consult a physician or dermatologist.

Dr. Mohammed El Damir, BCE

Dr. Mohammed El Damir, BCE

If no pests are located, the next step is to be aware that a delayed reaction to bites can be the cause. Bites of bed bugs, fleas, chiggers, and ticks may not be noticed by some people until hours or days after being bitten. This leads to the possibility that they have been bitten somewhere else outside their homes.

If none of the above causes is applicable, discuss with the affected individual the possibility that mysterious “bites” could be caused by environmental or medical conditions. For example, several drugs and vitamins can cause unexplained itching. Changing the medications by authorized physicians can solve the problem. In addition, be advised that indoor environments are filled with high static electricity that can cause tiny fibers, paper, and fiberglass particles to jump onto exposed skin. Once on the skin, these elements can cause skin irritations that feel or even look like bites. Low humidity, electrical equipment, nylon, leather, hair, wool, fur, aluminum, and paper tend to give and add to static electricity (Waldron, 1962; Scott and Clinton, 1967).

Finally, if all the above factors are fully discussed and no bugs are captured after reasonable monitoring, you can reasonably assume that the customer is exhibiting DP or cleptoparasitosis. In this case, it’s time to refrain from using any form of pesticides. Instead, document all inspection and monitoring findings, along with the discussions of all possible non-pest related causes of mysterious “bites.”

To conclude, once in a while, you may face challenging situations that are not related to a cryptic pest hiding in tough places, but rather are linked to the customer’s awareness, perspective, behavior, or attribute. To overcome these challenges, you should follow up with a series of inspections and monitoring to see what that does and ensure that communication and customer education are keys to dealing with mysterious “bites.”

Read more the DP phenomenon on the Pest Management Professional website. 


  • Grace, J.K, and Wood, D.L. 1987. “Delusional cleptoparasitosis: delusions of arthropod infestations in the home.” Pan-Pacific Entomol. 63: 1–4.
  • Scott, HG and Clinton, JM. 1967. “An investigation of ‘cable mite’ dermatitis.” Ann. Allergy 25: 409–14.
  • Hudson, B. W., Feingold, B. F. and Kartman, L1960. “Allergy to flea bites. I. Experimental induction of flea-bite sensitivity in guinea pigs.” Exp Parasitol. 9: 18–24.
  • Mellanby, K. 1946. “Man’s reaction to mosquito bites,” Nature, 158: 554.
  • Sansom, J. E., Reynolds, N. J. and Peachey, R. D. 1992. “Delayed reaction to bed bug bites.” Arch Dermatol.128: 272–273.
  • Waldron, W. G. 1962. “The role of the entomologist in delusory parasitosis (Entomophobia).” Bull. Entomol. Soc. Am. 8: 81-83.
  • Wikel, S.K. 1996. “Host immunity to ticks.” Annu Rev Entomol. 41: 1–22.


About the Author

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Dr. Mohammed El Damir, BCE, is technical and training director of Adam’s Pest Control, Medina, Minn.

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