eMedicine Specialties > Dermatology > Psychocutaneous Diseases

Delusions of Parasitosis: Follow-up

Author: Noah S Scheinfeld, MD, JD, FAAD, Assistant Clinical Professor, Department of Dermatology, Columbia University; Consulting Staff, Department of Dermatology, St Luke's Roosevelt Hospital Center, Beth Israel Medical Center, New York Eye and Ear Infirmary; Private Practice
Contributor Information and Disclosures

Updated: Feb 12, 2008

Follow-up

Further Outpatient Care

  • After medication has cleared the DP, it should be continued for several months and then discontinued.
  • Often, patients come to think that the medication has killed the bugs, and many (but not all) have a remission of their delusions.

Complications

  • If DP is not treated, scarring can result. The patient's entire life and family may be disrupted by their distress and attempts at treatment.
  • Therapy for DP can cause adverse effects.
    • Pimozide can result in tardive dyskinesia and akathisia.
    • Extrapyramidal reactions have been reported to occur in approximately 10-15% of patients taking pimozide.
    • Pimozide can have cardiotoxic effects at high doses. It may cause ECG changes such as prolongation of the QT interval, T-wave changes, and the appearance of U waves.
  • Lim et al24 noted an incidence of camphor-related, self-inflicted keratoconjunctivitis secondary to DP.

Prognosis

  • Many patients with DP refuse treatment and are lost to follow-up.
  • For those patients who can be convinced to undertake treatment, the prognosis for a remission of the delusions is good.

Patient Education

  • Patients must be reassured that they are not alone and that the physician will listen to them and sincerely desires to help them to get better.
  • While one should not say anything to confirm the delusion, it is usually not helpful to forcefully confront patients with DP.
  • Statements such as the following might be helpful: "I know you feel strongly that there are parasites here, and I'm sure that you itch severely, but I cannot prove that parasites are or have been the cause of your problem."
  • For excellent patient education resources, visit eMedicine's Mental Health and Behavior Center.
  • Medscape's Patient-Provider Relations in Psychiatry & Mental Health Resource Center may provide additional helpful informaiton.

Miscellaneous

Medicolegal Pitfalls

  • DP is a real entity, and untreated patients pick at themselves, causing scarring. Although attempts to stop this behavior are often unsuccessful, they should be made anyway to prevent morbidity.
  • The diagnosis is one of exclusion, and other diseases that can also cause a sensation of itching (eg, internal disease, actual infestation) must be considered, investigated, and treated if present.
  • Adverse effects of pimozide and other psychiatric medications must be discussed in a manner that patients are informed of the risks but not deterred from therapy.
 


More on Delusions of Parasitosis

Overview: Delusions of Parasitosis
Differential Diagnoses & Workup: Delusions of Parasitosis
Treatment & Medication: Delusions of Parasitosis
Follow-up: Delusions of Parasitosis
References
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References

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  3. Waddell AG, Burke WA. Morgellons disease?. J Am Acad Dermatol. Nov 2006;55(5):914-5. [Medline].

  4. Murase JE, Wu JJ, Koo J. Morgellons disease: a rapport-enhancing term for delusions of parasitosis. J Am Acad Dermatol. Nov 2006;55(5):913-4. [Medline].

  5. Marris E. Mysterious 'Morgellons disease' prompts US investigation. Nat Med. Sep 2006;12(9):982. [Medline].

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Further Reading

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Keywords

DP, DOP, insect infestation, matchbox sign, monosymptomatic hypochondriacal psychosis, delusion of infestation, delusional parasitosis, delusional infestation, folie à deux, folie partagé, morgellons disease.

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Contributor Information and Disclosures

Author

Noah S Scheinfeld, MD, JD, FAAD, Assistant Clinical Professor, Department of Dermatology, Columbia University; Consulting Staff, Department of Dermatology, St Luke's Roosevelt Hospital Center, Beth Israel Medical Center, New York Eye and Ear Infirmary; Private Practice
Noah S Scheinfeld, MD, JD, FAAD is a member of the following medical societies: American Academy of Dermatology
Disclosure: Nothing to disclose.

Medical Editor

Franklin Flowers, MD, Chief, Division of Dermatology, Professor, Department of Medicine and Otolaryngology, University of Florida College of Medicine
Franklin Flowers, MD is a member of the following medical societies: American College of Mohs Micrographic Surgery and Cutaneous Oncology, Lipoplasty Society of North America, Southwest Pediatric Nephrology Study Group, Southwestern Oncology Group, Southwestern Surgical Congress, Special Operations Medical Association, State Medical Society of Wisconsin, Swedish Medical Association, Sydenham Society, Tennessee Medical Association, Tennessee Radiological Society, Texas Medical Association, Texas Pediatric Society, Texas Society of Plastic Surgeons, Undersea and Hyperbaric Medical Society, Uniformed Services Academy of Family Physicians, United States and Canadian Academy of Pathology, United States Pharmacopeial Convention, US Virgin Islands Medical Society, Utah Medical Association, Vermont State Medical Society, Vestibular Disorders Association, Virginia Society of Otolaryngology-Head and Neck Surgery, West Virginia State Medical Association, Western Occupational and Environmental Medical Association, Western Orthopaedic Association, Western Section American Urological Association, Western Surgical Association, Wilderness Medical Society, World Association of Societies of Pathology and Laboratory Medicine, World Medical Association, World Society for Stereotactic and Functional Neurosurgery, and Wyoming Medical Society
Disclosure: Nothing to disclose.

Pharmacy Editor

David F Butler, MD, Professor of Dermatology, Texas A&M University College of Medicine; Director, Division of Dermatology, Scott and White Clinic; Director Dermatology Residency Training Program, Scott and White Clinic
David F Butler, MD is a member of the following medical societies: Alpha Omega Alpha, American Academy of Dermatology, American Medical Association, American Society for Dermatologic Surgery, American Society for MOHS Surgery, Association of Military Dermatologists, and Phi Beta Kappa
Disclosure: 3M Pharmaceutical Grant/research funds Other; Graceway Pharmaceuticals Grant/research funds Other

Managing Editor

Jeffrey Meffert, MD, Assistant Clinical Professor of Dermatology, University of Texas Health Science Center-San Antonio
Jeffrey Meffert, MD is a member of the following medical societies: American Academy of Dermatology
Disclosure: Nothing to disclose.

CME Editor

Catherine Quirk, MD, Clinical Assistant Professor, Department of Dermatology, Brown University
Catherine Quirk, MD is a member of the following medical societies: Alpha Omega Alpha and American Academy of Dermatology
Disclosure: Nothing to disclose.

Chief Editor

Dirk M Elston, MD, Director, Department of Dermatology, Geisinger Medical Center
Dirk M Elston, MD is a member of the following medical societies: American Academy of Dermatology
Disclosure: Nothing to disclose.

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