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Pest Control's Role in Classic Delusions of Parasitosis

Stylized worms
People with delusions of parasitosis are convinced that "things" are biting them, or are crawling and burrowing into or out of their body.
Graphic © Spectral-Design/iStockphoto

Delusions of Parasitosis

The worms crawl in, the worms crawl out
They crawl in your stomach and out your mouth
One little worm that isn’t shy
Crawls in your ear and out your eye

- lines from a traditional children’s song


Once in a great while, you will come face-to-face with a customer with a full-blown case of delusional parasitosis: an unshakable belief that bugs, parasites, or worms are crawling, biting, and burrowing into and out of his or her body.

We are not referring here to that far more common problem where people in a crowded office become convinced they are being bitten by “paper mites” or “cable mites.”

Such cases typically can be traced to real skin irritations caused by static electricity, carpet fibers, dry skin, paper splinters, fiberglass fibers, etc. A pest control company often has a role in these types of “mystery bug bite” cases: eliminating real pests from consideration, identifying possible environmental irritants, and working with other specialists to find the actual cause and solve the problem (see Dealing with Paper Mites, Cable Mites, and Other Mystery Bugs).


Anguished woman
Classic delusional parasitosis can be a serious and even dangerous mental illness.
Photo © Cliff Parnell/iStockphoto

There are major differences between these common “mystery bug” cases and classic delusional parasitosis, where the sufferer has a serious mental illness requiring the intervention of a psychiatrist. This can be a dangerous condition with the sufferer often experiencing suicidal thoughts.

It is a sad and frustrating experience dealing with people suffering classic delusional parasitosis. You want to help, but you can’t, because their problem is, truly, all in their mind. They categorically reject any suggestion that their bugs or worms are not real. Only in very rare cases will you be able to convince them that they should see a physician, and never, in our experience, will they consider seeing a psychiatrist. In fact, they will typically get fiercely angry if you even mention the words psychology or psychiatry or “imaginary.”


Recognizing Delusional Parasitosis

So, what should you do? First, learn how to recognize delusional parasitosis. Sufferers typically say their bugs, parasites, or worms:

  • burrow in and out of the skin, or go in and out of body openings such as nostrils, ears, anus, genitals;
  • infest various internal organs, and may be found in body fluids;
  • change form or color to avoid detection;
  • come out of common household items such as toothpaste, Vaseline®, cosmetics, upholstered furniture;
  • attack other family members who cannot see them.

The person suffering from classic delusional parasitosis may exhibit any of the following signs and symptoms:

  • spends hours every day cleaning, scrubbing, and sterilizing clothes, skin, furniture, and fixtures, even vehicles;
  • treats skin and clothes with pesticides, gasoline, kerosene, toxic chemicals, and various home remedies;
  • moves out of home (rarely) and destroys “infested” furniture and fixtures;
  • has sores and even deep ulcerations from trying to “dig out” the parasites, worms, or bugs (some people mutilate themselves seriously, both externally and internally);
  • eagerly and repeatedly recites a detailed history of the condition, with all the steps taken to resolve it;
  • angrily rejects any idea that the bugs don’t exist;
  • has consulted with numerous pest control companies, entomologists, university professors, and other “experts” on human parasites, shopping for anyone to agree that they are infested. You may be told that you’re their “last hope”;
  • exhibits “matchbox sign”—offering boxes or plastic bags with samples of skin scrapings, dried blood and scabs, toilet paper, hair, and lint “proving” that their problem is real.

Sometimes more than one family member will share the delusions, usually a husband and wife, and rarely an entire family.

The Role of the Pest Control Professional

Whether you are a technician, manager, or entomologist, you have a very limited role to play in severe cases of delusional parasitosis. To be sure, you should check that there are no pests involved. But you are not a parasitologist or physician, so do not be manipulated into checking out the person’s body, clothes, or specimens.

inspecting furniture
Limit your inspection to the premises; don't inspect the person's body or medical "samples."
Photo © Pinto & Associates

Limit your inspection to the premises. In these cases, as opposed to the “paper mite” type of case, you usually know in your gut that the problem is medical or psychological and not pest control-related. Simply state to the person that you could find no pests and so you can do nothing more. Advise them to check with a physician or a dermatologist. Most experts agree that it is pointless to argue with the sufferer as there is no way to sway them.

And most critically, don't agree with the sufferer just to placate them, you will only make the situation worse.

Someone with delusional parasitosis may follow advice to consult a physician. Your hope, of course, is that once in the medical field they will eventually get psychiatric help. Consider giving them copies of articles such as this one discussing delusional parasitosis; it may plant a seed that perhaps a psychiatrist could help them. There are also information resources on the world wide web.


One excellent web site is Delusional Parasitosis out of the University of California, Davis. It includes definitions, literature, diagnostic protocols, clinical manifestations, and other information on the topic. U.C. Davis also provides analysis of samples. For a fee ranging $55-115 per sample, entomologists and parasitologists determine if any biological agents are present.

What is missing, though, is a specialized medical clinic dedicated to evaluation of delusional parasitosis. There was a clinic in Vienna, Austria called the Liaison Out-Patient Clinic for Dermatology, Parasitology, and Psychiatry that dealt with this condition through an interdisciplinary approach. It operated during the late 1990s, but we could not determine if it was still in business today.

We need similar clinics staffed with entomologists, dermatologists, psychiatrists, etc. so that a person suffering from possible delusional parasitosis could be referred there to be evaluated. Such a referral would be far better received by the sufferer than telling them they need to see a psychiatrist because “it’s all in their head.”.


Dealing with "Paper Mites," "Cable Mites," and Other Mystery Bugs in Offices

How to Evaluate with Mystery Bugs

For a PDF file of a recent (10/22/06) article in Techletter, click Inspection Sheet—Delusory Parasitosis

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