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Ohio State University Extension


Mystery Bugs and Bites

David J. Shetlar, Department of Entomology
Jennifer E. Andon, Department of Entomology

In the United States, there are only a few arthropods that bite humans and are capable of producing discernible skin reactions. Even fewer are capable of living in human bodies. Periodically, everyone suffers from illusory parasitosis, or symptoms perceived to be caused by insects or another arthropod, when they watch insect or spider horror movies or see mites, ticks or fleas on television. In other cases, static electric charges, allergenic dust, cleaner residues, even clothing can cause sensations of bites or something crawling on the skin. These perceptions are quickly overcome when an alternate explanation is presented and acknowledged. Entomophobia is a persistent, irrational fear and compelling need to avoid insects, spiders and mites, when no arthropod or bite is present. Sufferers of delusory parasitosis are convinced that bites or infestations actually exist and will often go to dangerous lengths to eliminate the imagined infestation. Illusions and delusions may be transferred to other family members or even to others in the workplace.

Common Symptoms of Delusory Parasitosis

Common sample received by Ohio State University diagnostic clinic from a client suspected of suffering delusory parasitosis. Photo: B. Bloetscher

Sufferers of delusory parasitosis often describe in great detail, the characteristics and behaviors of the infesting "bugs." Some observe microscopic bugs that frequently change color or may disappear. Others describe biting or burrowing into their skin, causing severe itching. Others describe small specks that may jump or fly. Description of unusual lifecycles, such as invading human digestive tracts, and emerging through various orifices (mouth, ears, eyes, genitals or anus are commonly described). Some blame the discomfort on paper mites, cable mites, dust fleas or other mythical arthropods. These delusions are often accompanied by persistent scratching and "digging out" insects from one's skin, which may result in secondary infection. Dangerous pesticides are used repeatedly, often applied in homes, but also to the body in an attempt to reduce the infestation. When pesticides aren't available, many will resort to unsafe home remedies or other household cleaners to get rid of the perceived infestation.

Most clients are only able to submit samples of skin fragments, scabs, lint, threads, wood splinters, dirt and other debris for identification. They feel frustrated and helpless and may sense that no one believes they have a problem. Many attempt to self-treat and/or have employed pest control operators to make pesticide applications or even fumigations to their homes in hope of eliminating the problem. Some claim that the "bugs" follow them around, infesting their vehicles, new apartments or homes. Because of this, they may be reluctant to visit friends or relatives. Most are desperate for answers and see one or more medical doctors on a regular basis for advice and treatment, to no avail.

Common Biting Arthropods

Bed bug adult.

In the United States, very few arthropods will bite humans and even fewer burrow into human skin. All are easy to see and diagnose by general physicians, dermatologists and entomologists. Arthropod bite reactions will vary significantly from person to person and for this reason, even a dermatologist can't determine what bit a person, solely based on the appearance of the bite. Red, itchy welts can be attributed to several different insects and arthropods, as well as plants, environmental factors, chemicals, medications and some rare diseases. Rare individuals are very sensitive to arthropod bites and may exhibit severe allergic reactions, even anaphylactic shock. This is more common with stings from bees and wasps. Most insect bite reactions will disappear in a matter of hours or days and can be safely treated at home.

The most common biting insects include mosquitoes and other biting flies (i.e., no-see-um, black flies). Parasites include bed bugs, lice (head, body and pubic), mites such as chiggers and bird mites, ticks and fleas. True spider bites are quite rare and are commonly misdiagnosed by physicians. The only arthropod capable of burrowing into the skin is the scabies mite. These are easily diagnosed by dermatologists. In extremely rare cases (an exposed skin wound, or by ingestion of contaminated food) fly maggots (myiasis) can infest human flesh. Again, these are easily diagnosed by a physician.


Many substances can cause allergic reactions, including house dust, animal dander, molds and mildews, laundry softeners, soaps (changing to a different detergent), cosmetics, wall paints, foods, pollens, medicines (including antibiotic drugs), vitamins, perfumes, insect fragments and clothing. Certain allergens can be inhaled, rubbed on the skin, taken by mouth or injected. An estimated 35 million Americans have allergies. Non-arthropod allergic reactions can produce dermatitis and similar reactions to arthropod bites.

Physical Causes

Physical causes may also induce the sensation of itching, crawling or other irritation to the skin.

  • Static electricity
  • Paper shards
  • Fiberglass pieces
  • Dry skin
  • Carpet fibers

Physiological Causes

There are many other reasons a person may experience delusory parasitosis symptoms. If it has been determined that an arthropod is not involved, a medical professional should be contacted for advice and possible treatment.

  • Some infectious and non-infectious diseases (i.e., AIDS, cirrhosis, hepatitis)
  • Some drugs and drug interactions (i.e., antibiotics, antidepressant, sedatives)
  • Recreational drugs (i.e., cocaine and methamphetamine)
  • Some herbal remedies
  • Stress, anxiety, depression
  • Neurological disorders

Control Measures

If one is convinced an arthropod is the cause, a specimen is imperative for an accurate diagnosis. To sample for potential pests, sticky insect glue board-traps can be placed near the bed, chairs, bathroom or any location or height where the victim is irritated. Scotch tape can be used to collect specimens from bedding, clothing, carpets, windows and skin. This is done to help establish the presence or absence of the causal organism. Samples from skin or body openings should be collected, preserved and submitted by medical personnel only. Samples may be submitted to the C. Wayne Ellett Plant and Pest Diagnostic Clinic at The Ohio State University. 

In cases where dry skin or dry air may be causing static changes or paper fiber itches, the following may provide some relief.

  1. Use a humidifier to increase relative humidity in your home or office.
  2. Filter the air (if a forced air system is used, ideally use a HEPA filter designed to trap smaller particles). Be alert to central overhead air systems with dirt and dust that air blast down onto persons seated directly below causing irritation.
  3. Static electricity can cause particles of carpet fibers, paper splinters, fiberglass fibers, etc., to jump onto arms and legs. See A. above. (Use a static guard for carpet and clothing. Some spray fabric softener.) Some have reaction to NCR self-carbon paper and paper dust from computer paper.
  4. Use moistening creams and lotions (avoid alcohol) frequently to prevent and treat dry skin.

Where allergies may be the cause of irritated skin, the following may be useful.

  1. Vacuum frequently and thoroughly. (Removes dust, molds, bacteria, animal dander from dirty carpets, etc.). However, sometimes new carpets or newly painted areas can cause problems.
  2. Adequate ventilation—Move fresh air into the house or building to improve indoor air quality. Avoid recirculating dirty, stale air. Mold and mildew can build up in humidifiers, dehumidifiers, refrigerators, etc., causing allergies, so these need to be cleaned regularly.
  3. Household and personal products—New laundry softeners, laundry or dishwashing soaps (especially ones with protein enzymes), hand and shaving creams, hair sprays, fingernail polish and deodorants can cause skin irritation. Also use of certain perfumes may need to be discontinued. Amount and type of clothing worn indoors (natural or man-made fibers) or the kind of yarn (dyes or wool type) used for knitting can cause irritations. New carpets, curtains, paints, wallpapers, bedding, etc., can cause itching.
  4. Poison ivy, poison oak and poison sumac can cause severe reactions. The smoke, ash, dead leaves and vines in infested areas should be avoided. Avoid burning poison ivy vines attached to firewood.
  5. Pollen (flowering plants of ragweed, cockle bur, burdock, daisies, carrots, celery, dill, chrysanthemums, etc.)
  6. Chemicals—Formaldehyde is a respiratory irritant found in no-press clothing, particle board, plywood, etc. (Symptoms include runny nose, cough, itch, etc.). Also, some are bothered by ammonia, paint and adhesive solvents, tobacco smoke, Azo Dyes, etc.

Finally, there are dozens of medications, both prescription and over-the-counter products that can cause tingling, itching or pin-prick sensations to human skin. Stresses (financial, marital, occupational, death in family, etc.), diseases (diabetes, liver or kidney disorders), food allergies (seafood, nuts, fruits, dairy products), vitamins (Biotin, Niacin), pregnancy, drug abuse and medications (antibiotics and blood pressure tablets) may cause irritation. Also, remember that everyone is susceptible to Bell's Syndrome (power of suggestion), where one person in an office or home will feel an itch and scratch vigorously. Others will later follow with itches and bites. 

This fact sheet is a revision of HYG-2123.

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Originally posted Aug 11, 2015.