Editor’s note: This Shark was intrigued by the Walsh article on delusional infestation. Your ProbateShark draws a comparison with the parasitic lawyers and judges employed by the Probate Court of Cook County who delude the victims netted into their evil web in order to relieve them of their freedom and property. Lucius Verenus, Schoolmaster, ProbateSharks.com

Bugs and Worms in Patients' Heads, Not the Skin

By Nancy Walsh, Staff Writer, MedPage Today

Published: May 16, 2011

Reviewed by Zalman S. Agus, MD; Emeritus Professor
University of Pennsylvania School of Medicine and Dorothy Caputo, MA, RN, BC-ADM, CDE, Nurse Planner

Action Points

• Note that delusional infestation is a condition where patients have a fixed belief that their skin is infested by animate and/or inanimate materials.
• Point out that in this restrospective study of patients with this condition there was no objective evidence of skin infestation, although many had evidence of dermatitis on biopsy.

Patients who thought that bugs, worms, or inanimate materials were crawling on their skin or living under it had no objective evidence of infestation, a retrospective study determined.
Among 80 patients complaining of delusional infestations who had biopsies, not one was positive, according to Mark D.P. Davis, MD, and colleagues from the Mayo Clinic in Rochester, Minn.
However, almost two-thirds of the patients had dermatitis, "raising the possibility that skin inflammation and its attendant tactile discomfort might be the trigger provoking delusional symptoms in susceptible individuals," the researchers observed online in the Archives of Dermatology.
Delusional infestation is a diagnostic term describing patients' fixed but incorrect beliefs that minute objects on or in their skin are causing them to experience symptoms of discomfort.
Many patients with this disorder bring specimens such as skin flakes, hair, and stool as proof of the infestation, believing that physicians dismiss their complaints and don't closely examine their skin.
Many ask for further testing, but no study as yet has evaluated the potential benefit of biopsy in this situation.
So Davis and his group reviewed the medical records of 108 patients with this diagnosis seen at their clinic between 2001 and 2007.
Three-quarters of the patients were women, and mean duration of symptoms was 2.3 years.
A total of 79% believed the infestation was with bugs, 20% with worms, and 3% with eggs (nearly half the patients felt they were infested by more than one type of object).
Inanimate materials included fibers in 22%, and substances such as gravel, glass, and car oil in a few patients.
Biopsies, most often of the skin, were done in 80 patients.
Eighty patients also brought specimens in bags, envelopes, and jars -- and only one specimen actually contained a parasite, which was identified as a pubic louse.
In that case, parasitic infestation could not be confirmed on physical examination, and lice could not explain the patient's many reported symptoms such as nail abnormalities.
Another patient who believed that eggs, mucus, and "snake skin-like" materials were passing rectally turned out to have perianal herpes simplex infection.
The patients whose biopsy specimens revealed dermatitis often had excoriations and crusting resulting from scratching.
These skin scabs and debris can further confirm patients' belief of the presence of pathogens or foreign material, the investigators explained.
In addition, many of the patients had used caustic irritants on their skin as self-treatment, which could have caused or exacerbated the dermatitis.
The authors noted that the study raised certain questions about the potential value of biopsies for these patients, such as whether such testing influenced the patient-physician interaction, or if patients might be more adherent to treatment after a biopsy is done.
A strength of the study was the objective evidence of the histologic analyses, while a limitation was its retrospective design.

All authors reported no financial conflicts.

Primary source: Archives of Dermatology
Source reference:
Hylwa S, et al "Delusional infestation, including delusions of parasitosis: results of histologic examination of skin biopsy and patient-provided skin specimens" Arch Dermatol 2011; DOI: 10.1001/archdermatol.2011.114.

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Nancy Walsh
Staff Writer
Nancy Walsh has written for various medical publications in the United States and England, including Patient Care, The Practitioner, and the Journal of Respiratory Diseases. She also has contributed numerous essays to several books on history and culture, most recently to The Book of Firsts (Anchor

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