Biology 625
ANIMAL PARASITOLOGY
Fall semester lecture note outline

Updated: 20 December 2006


The text below simply represents a crude lecture outline of one of the topics covered in class. It is not meant to substitute for attending lectures or ignoring the textbook. Additional material, including line drawings, kodachromes, and more extensive information on life-cycles and basic biology, will be supplied in the lectures.


TOPIC 54. Delusional parasitosis (Ekbom's syndrome II)


  1. Delusional parasitosis, or Ekbom's syndrome II, is the mistaken belief that one is being infected by parasites (Ekbom's syndrome I is restless leg syndrome).
  2. A new term that has appeared in the literature is "Morgellon's disease." This term is limited to the skin aspect of the disease only.
  3. The most common types of parasites imagined include mites, worms, lice, and fleas
  4. Common clinical signs and symptoms of Ekbom's syndrome II
    1. a long term feeling of itching, particularly of the skin, and soreness of the skin, anal region, gut, and/or nose
    2. most individuals have visited numerous physicians, health care workers, dermatologists, and even parasitologists, etc. and have rejected negative findings
    3. individuals frequently mail out samples consisting of dried flakes of skin, hair, scabs, exudates, etc. often mixed with toilet paper, dust, or lint. No parasites are generally found by the professionals
    4. often these individuals convince family members of the problem so that multiple family members become involved
    5. many individuals begin to spend large sums of money on bogus home remedies, including herbal remedies, when conventional drugs fail to provide satisfaction. Indeed, several webpages now exist that foster this belief in order to get affected individuals to order various herbal remedies
    6. some individuals expose themselves to intense washings with soaps, disinfectants, and dangerous levels of pesticides
    7. patient will often complain of seeing small worms or bugs crawling on or in the skin, emerging out the nose or through sores in the skin, or deposited on furniture
    8. patients may begin to self-mutilate, rubbing the skin or anal area so hard that weeping sores appear
  5. Correlations (not everyone fits into these categories, however)
    1. often high stress and loneliness
    2. 2/3 female, often divorced with children; 1/3 male, often with alternate life-style
    3. sometimes low self esteem
    4. socially introverted
    5. often lower income than national average
    6. average intelligence
    7. varied backgrounds
    8. generally non-entomophobic
    9. generally non- bizarre personalities
  6. Typical causes of dermal irritations
    1. environmental irritations such as laundry detergent perfumes, soaps, shampoo, perfumes, make-up, synthetic fibers, cleaning solutions, pesticides
    2. some individuals experience delusional parasitosis because of drug use or other substance abuse
    3. some people simply have mental disorders (paranoia, depression, schizophrenia)
    4. various underlying diseases such as cancer, diabetes, hypothyroidism, heart disease, tuberculosis, vitamin B12 deficiency, etc.
    5. the person may actually have a skin parasite (Sarcoptes scabei, Strongyloides stercoralis, Pthirus pubis, etc.)
    6. often times, no overt cause can be determined. People are otherwise normal
  7. Treatment options include supportive psychotherapy when other causes are ruled out. Several drugs, including risperidone, primozide, and sertindole, have all been used to successfully treat some patients.

As a parasitologist, I occasionally receive letters, e-mails, or telephone calls from individuals experiencing Ekbom's syndrome II. I've now learned from experience not to become involved in these cases since, to date, I have been unable to convince any of these individuals that they are not infected. All samples I've looked at, which include skin scrapings, serous exudates, nasal exudates, saliva, feces, and urine samples, are uniformly negative for parasites. However, the samples submitted usually consist of one of two items: 1) dried exudates with a bit of hair; the exudates sometimes resemble arthropods in shape only and the hairs are mistaken for pieces of worms, or/and 2) dried exudates containing paper fibers from toilet paper, napkins, and paper towels that the patients use to rub and sample self-inflicted wounds. These paper fibers are normally mistaken by these patients for pieces of nematodes.

Although I discard 90% or more of the correspondence I receive from individuals suffering from Ekbom's syndrome II, over the years I've saved a few of the e-mails for teaching purposes. Below I provide several actual letters from patients who have contacted me in the past, although I have been very careful to delete any information (names, dates, geographic locations, etc.) that might provide a clue as to an individual's identity. I have also left all spelling and grammatical errors intact. In one case I felt compelled to contact the student health center at the College in question since I felt that the individual, a student, might do something to hurt herself.

  1. letter01 (.pdf)
  2. letter02 (.pdf)
  3. letter03 (.pdf)
  4. letter04 (.pdf)
  5. letter05 (.pdf)


Further reading

Berrios, G.E. 1985. Delusional parasitosis and physical disease. Comp. Psych. 26: 395-403.
Bhatia, M.S. et al. 2000. Delusional parasitosis: a clinical profile. Intl. J. Psych. Med. 30: 83-91.
Bourgeois, M.L. et al. 1992. Delusional parasitosis: Folie a deux and attempted murder of a family doctor. Br. J. Psych. 161: 709-711.
Koblenzer, C.S. 1993. The clinical presentation, diagnosis and treatment of delusions of parasitosis-a dermatologic perspective. Bull. Soc. Vector Ecol. 18: 6-10.
Lyell, A. 1985. Delusions of parasitosis. In, Cutaneous infestations and insect bites. Orkin, M. and Maibach, H.I., eds. Marcel Dekker Inc., New York. pp. 131-137.
Mitchell, C. 1989. Successful treatment of chronic delusional parasitosis. Br. J. Psych. 155: 556-557
Musalek, M. and Kutzer, E. 1990. The frequency of shared delusions in delusions of infestation. Eur. Arch. Psychiatr. Neurol. Sci. 239: 263-266.
Rasanen, P. et al. 1997. Delusional parasitosis in the elderly: a review and report of six cases from Northern Finland. Int. Psychogeriatrics 9: 459-464.
Slaughter, J.R. et al. 1998. Psychogenic parasitosis. A case series and literature review. Psychosomatics 39: 491-500.
Trabert, W. 1995. 100 years of delusional parasitosis. Psychopathology 28: 238-246.
Trabert, W. 1998. Shared psychotic disorder in delusional parasitosis. Psychopathology 32: 30-34.
Webb, J.P. 1993. Case histories of individuals with delusions of parasitosis in southern California and a proposed protocol for initiating effective medical assistance. Bull. Soc. Vector Ecol. 18: 16-25

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