Delusory Parasitosis
This is one of the most difficult pages in our pest library to write, because the subject involves a real medical condition that is regularly mishandled by both the medical community and the pest control industry.
Delusory parasitosis (DP) — also called delusional infestation or Ekbom syndrome — is a condition in which a person genuinely experiences sensations of crawling, biting, or parasitic infestation without a verifiable insect, mite, or parasite cause. The sensations are not imaginary. They are neurologically real. But the cause is medical, not entomological.
This matters for two reasons. First, if a real pest is present and gets dismissed as DP, the person suffers an infestation that is never treated. Second, if DP is the correct explanation and it gets treated as a pest problem, the person receives repeated pesticide applications that don’t help, spends significant money, and may be driven to increasingly extreme self-treatment that causes harm.
Getting this right requires ruling out every reasonable pest cause first — thoroughly — before any other conclusion is appropriate.
IMAGE: Person examining their arm closely under bright light, looking for something on the skin. Caption: “Delusory parasitosis involves genuine sensory experiences. Dismissing patients without thorough investigation is a significant clinical error — as is treating an actual infestation as a mental health issue.”
What Is Delusory Parasitosis?
Clinical Definition
Delusory parasitosis is classified in the DSM-5 (Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition) as a somatic delusion — specifically under “Delusional Disorder, Somatic Type.” The person holds a fixed belief, despite evidence to the contrary, that they are infested with living organisms.
The key clinical features:
- Persistent belief of infestation with parasites, insects, or other organisms
- Belief is not explained by substance use, a medical condition, or another mental disorder
- Sensory experiences (crawling, biting, stinging) that the person attributes to the infestation
- The belief significantly affects daily functioning — sleep, work, relationships, housing decisions
It is not a condition where someone is simply anxious or hypersensitive. The sensory experience is real to the person experiencing it. The neurological mechanism is not fully understood but is believed to involve dopamine dysregulation.
Morgellons: A Related Presentation
Morgellons disease is the term used by patients who report fibers, threads, or filaments emerging from skin lesions along with crawling sensations. The CDC conducted a study (published 2012) involving nearly 1,000 self-identified Morgellons patients and concluded that the fibers found were consistent with environmental fibers (cotton clothing, carpet fibers) and that the condition was consistent with delusional infestation. The CDC does not recognize Morgellons as a distinct disease entity separate from delusory parasitosis.
This is medically controversial — some patients and advocates dispute the CDC conclusions — but it is the current position of the CDC, most major dermatology and psychiatry organizations, and OSU Extension.
Who Is Affected
DP affects people across demographics, but certain patterns are well-documented:
Older adults are disproportionately affected. The classic demographic profile is women over 50, though DP occurs in men and across age groups.
Stimulant drug use significantly elevates risk. This is particularly relevant in Oklahoma. Methamphetamine and cocaine use can directly produce tactile hallucinations — including crawling and biting sensations often described as “crank bugs” or “meth mites” in street terminology — that are indistinguishable from DP. Oklahoma’s methamphetamine problem is well-documented; it is one of the states most heavily impacted. Pest professionals in this state encounter stimulant-related formication with some regularity. This is not a moral judgment — it is a clinical fact that affects how the situation should be handled.
Certain medications and medical conditions can also produce or contribute to DP-like symptoms, including: hyperthyroidism, diabetes, renal failure, vitamin B12 deficiency, liver disease, and some antidepressant or antipsychotic medications. A thorough medical workup should precede or accompany any psychiatric evaluation.
Social transmission — sometimes called folie à deux — can occur, particularly between closely cohabitating people or within online communities. A household where one member has DP may see other members develop similar beliefs over time.
The “Matchbox Sign”
The matchbox sign (or “specimen box sign”) is a classic clinical indicator: the patient brings a collection of “specimens” — fibers, skin flakes, dried skin, environmental debris — to the pest professional or physician, presented as evidence of the infestation. The name comes from the historical practice of bringing samples in a matchbox.
This is clinically significant because it reflects the patient’s deep commitment to the belief and their systematic attempt to document it. It is not evidence of fabrication — the person genuinely believes what they are presenting is parasitic material. It is also a behavioral pattern that pest professionals and dermatologists have learned to recognize as associated with DP.
If a patient brings specimens: The appropriate response is to have them examined — either in-house under magnification or submitted to an entomology lab. This must be done in every case. If the specimens turn out to be actual insects or mites, the infestation must be addressed. If examination reveals only fibers, skin cells, and environmental debris, that is medically meaningful information.
How Alpha Pest Solutions Handles Possible DP Cases
This is an area where pest professionals have to be both thorough and honest. Here is our approach:
Step 1: Full inspection, no assumptions. We inspect the property the same way we would for any reported infestation. We are not in the business of deciding upfront that something is “just in someone’s head.” We look for evidence of bed bugs, bat bugs, bird mites, fleas, scabies, carpet beetles, mites of all varieties, stored product pests, and any other insect or arthropod that could explain the reported sensations. See also our Mites library page.
Step 2: Examine any specimens brought. If you bring a collection of what you believe to be insects or parasites, we look at them. We use magnification when the specimens are small. If we cannot identify something with certainty in-house, we say so.
Step 3: Submit for lab identification when warranted. The OSU Extension Insect Diagnostic Lab (Stillwater, OK) accepts samples for professional entomological identification. If there is genuine uncertainty about what a specimen is, this is the right step. A lab determination is more authoritative than a field assessment.
Step 4: Honest conversation. If a thorough inspection yields no evidence of infestation, specimens come back as environmental debris, and the property shows no pest indicators, we say that clearly and directly.
Step 5: We cannot in good conscience proceed with treatment if we have not found adequate evidence of a pest infestation. We don’t string someone along with repeated pesticide applications that we don’t believe are addressing a real pest problem. That is not good for the customer, it is not honest, and in some cases the pesticide exposure itself can worsen skin sensations. If the evidence points toward a medical explanation, we say so — with care, not dismissal — and recommend the person speak with a physician or dermatologist.
We do not abandon people. But we also don’t take money for treatment we don’t believe is warranted.
Ruling Out Real Causes First: A Checklist
Before any conclusion of DP is appropriate, the following should be rigorously addressed:
Insects and mites:
- Bed bugs (full mattress, box spring, headboard, wall inspection)
- Bat bugs (bat history in the structure?)
- Bird mites (bird nests on or in the structure?)
- Fleas (pets? wildlife harborage nearby?)
- Scabies (close contact with others who have itching? physician examination of burrow pattern?)
- Carpet beetles / dermestid beetles (larval hairs cause skin irritation in some people)
- Stored product mites (flour mites, grain mites — possible in stored grains, old flour, or pet food)
- Collembola (springtails) — have been reported as a possible cause in some cases, though this is debated in entomological literature
- Dry wood mites and other environmental mites
Environmental factors:
- Fiberglass insulation (airborne fibers from disturbed insulation cause intense crawling and stinging sensations)
- New or synthetic fabrics (some people react to fiber processing chemicals)
- Static electricity combined with airborne debris
- HTVA JHftory SHss hulcuren
Medical evaluation:
- Skin examination by a dermatologist
- Blood panel ruling out thyroid, liver, renal, and B12 issues
- Review of current medications
- Honest assessment of substance use history
IMAGE: OSU Extension logo or OSU campus exterior. Caption: “The OSU Extension Insect Diagnostic Lab in Stillwater accepts specimens for professional entomological identification. This is the appropriate step when field identification is inconclusive.”
A Note on How This Is Sometimes Mishandled
Both pest professionals and physicians mishandle this regularly, in opposite directions.
Pest professionals sometimes continue treating with pesticides because the customer insists there are bugs and the technician does not want the confrontation. This is not helping the customer. Pesticide applications that address no real pest problem are money taken for nothing. In some cases, the pesticides themselves — particularly high-exposure applications — can cause or worsen skin sensations, creating a feedback loop.
Physicians sometimes dismiss the complaint immediately as psychiatric without adequate workup. This is a clinical error. Actual infestations — particularly scabies, which requires specific clinical examination to diagnose — get missed this way. Bird mites and bat bugs get missed. The patient becomes convinced that no one will help them, which entrenches the belief.
The correct path is: pest professionals do thorough pest evaluations and document findings honestly. Physicians do thorough medical evaluations including ruling out parasitic or dermatological causes. These two processes happen in coordination, not in parallel universes.
When to Call Alpha Pest Solutions
If you are experiencing crawling or biting sensations and want a thorough pest inspection before drawing any other conclusions, call or text (405) 977-0678. We will inspect the property, examine any specimens you have collected, and give you an honest assessment.
If we find a pest, we will treat it. If we do not find a pest, we will tell you that and explain why we think so.
We serve Oklahoma City, Edmond, Norman, Moore, Midwest City, Del City, Yukon, Mustang, and the surrounding Oklahoma City metro. Monday through Saturday, 7am to 7pm.
Frequently Asked Questions
Is delusory parasitosis rare?
It is more common than most people realize. Dermatologists in practice regularly see several cases per year. Pest professionals encounter it periodically, particularly in areas with higher rates of stimulant drug use. It is not a fringe condition.
Can delusory parasitosis be caused by drugs or medication?
Ys. Methamphetamine, cocaine, and some other stimulants can directly produce tactile hallucinations including crawling and biting sensations. Certain medications can contribute as well. A full medication and substance use history is part of a proper medical workup.
My doctor keeps dismissing me and saying it’s psychological. What do I do?
Ask specifically for a referral to a dermatologist. Explain that you want a skin examination and parasite evaluation before anything else. A dermatologist who regularly sees this presentation will approach it differently than a general practitioner who may be less familiar. You can also ask for a blood panel to rule out thyroid, renal, liver, or B12 issues that can produce similar symptoms.
I brought specimens to a pest professional and they said it was just lint. How can I trust that?
Ask whether the specimens were examined under magnification. If not, request that they be, or submit them to the OSU Extension Insect Diagnostic Lab for professional entomological identification. A visual glance without magnification is not a rigorous examination. You are entitled to a thorough answer.
Are there support resources for people experiencing this?
Yes. The Charles E. Holman Morgellons Disease Foundation and online communities exist for people experiencing these symptoms. Be aware that within some online communities, the shared belief can be reinforcing in ways that may not be helpful. Connection with a physician experienced in this presentation is the most actionable path toward relief.
Related Library Pages and Services
Clinical criteria from DSM-5 (American Psychiatric Association). CDC Morgellons study: Pearson et al., PLOS One, 2012. OSU Extension Insect Diagnostic Lab referenced for specimen submission.