Identifying Delusional Parasitosis

San Antonio Express News
Sunday, January 11, 2004

By Nathan Riggs

How many times have you been outdoors, in the car, or even withing the safe confines of your home, and had the feeling that critters were crawling on your skin? Do you feel like things are biting you? If you do, you are not alone. Each year millions of people get these strange sensations on their skin and become so profoundly disturbed that they require medical or psychological treatments for relief. In some of these cases, there are insects or mites to blame. In the others, there are a wealth of reasons on which to pin the blame. Allow this week’s article from the Bexar County Extension office to soothe your mental ills.

As if we don’t have enough to worry about, for some, insects represent a real fear element. Just the thought of an insect can send the most sane person into fits of insanity. The good news is that this disorder has a name: delusional parasitosis (DP). Delusional parasitosis is defined as a mistaken belief that one is infested by mites, lice, fleas, spiders, worms or other organisms. For a person with this disorder, the belief is real, and it is very difficult to convince them otherwise. Let’s look at a few tips and symptoms of this disorder in detail.

A person suffering from DP usually has the infestation for a long time, has seen many doctors, exterminators, entomologists, and consistently or fiercely rejects any negative findings or findings that deviate from their personal perception of the infestation. Frequently, sufferers exhibit what are called “matchbox signs” where they mail or deliver samples in small containers. The samples may consist of dust, lint, skin scrapings, hair, fibers or scabs. Sometimes sufferers damage their skin by attempting to dig out the “parasites.” A strong dependence on home remedies and self exposure to dangerous levels of pesticides, coupled with a distrust of prescription drugs is a frequent characteristic of someone living with DP.

The best way to treat or deal with DP is to first check with an entomologist to look for signs of insects or mites. Next, check with a physician or dermatologist to address the skin problems or other physical symptoms occurring. Lastly, if the problems cannot be resolved, a psychiatrist may be needed to assist the sufferer and help them to live more comfortably with DP.

Now that we’ve talked about the clinical signs of DP, let’s look at some other stimuli that would cause our skin to “crawl” or otherwise feel itchy or prickly. In winter, the primary cause of itchy, prickly skin is low humidity associated with cold, dry air from cold fronts, or hot, dry air associated with furnaces indoors. Either of these, paired with static electricity can certainly make the skin crawl. Some people are extra sensitive to perfumes and other ingredients found in soaps and detergents. These too, can cause rashes and other skin problems. Don’t forget about pesticides, too. For those with DP, repeated misuse of foggers, lice cream or mite creams can cause hypersensitivity that usually appears as some sort of skin malady such as a rash, hives or other problem. Be sure to use pesticides and lice/mite products as directed by a physician or by following label directions.

Now that we’ve talked about non-insect related problems, let’s talk briefly about actual problems. Insects that are very small and can bite without being seen include thrips, minute pirate bugs, lice, fleas, mosquitoes and no-see-ums (biting flies). Fleas, mosquitoes, lice, and no-see-ums do feed on blood while thrips and minute pirate bugs seem to bite for no reason at all. Other pests that can cause rashes and skin irritations include fowl mites, rat mites, grocer’s itch mites, chiggers, grain mites and scabies mites. Of these mites, only scabies mites actually burrow in the skin and lay eggs. The rest of these mites only feed on skin fluids and cause severely itchy welts.

Having a personal insect or mite infestation and thinking you have one are two entirely different topics. For those who are infested, there are plenty of ways to successfully deal with the problem once it is understood and diagnosed. For those who suffer from delusional parasitism and truly believe that they are infested when there are no insects or mites present, the road to recovery is much longer and requires patience, an open-minded approach and support from family and friends, in addition to help from physicians, dermatologists, entomologists, and psychiatrists.

Information on delusional parasitism for this article was obtained from a wonderful website developed by the University of California-Davis and the address on the web is

This article was written by Nathan Riggs, Extension Agent-IPM with Texas Cooperative Extension in Bexar County.

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