Delusions of Parasitosis

Back

Background

Delusions of parasitosis (DoP) manifest in the patient's firm belief that he or she has pruritus due to an infestation with insects. Patients may present with clothing lint, pieces of skin, or other debris contained in plastic wrap, on adhesive tape, or in matchboxes. They typically state that these contain the parasites; however, these collections have no insects or parasites. This presentation is called the matchbox sign, or what the authors term the "Saran-wrap sign."

The patients have no obvious cognitive impairment, and abnormal organic factors are absent. True infestations and primary systemic diseases that cause pruritus are not involved. Primary skin lesions are not present. Physical examination may reveal no lesions, but only linear erosions with crusts, prurigo nodularis, and/or ulcers.

The classification of delusions of parasitosis is complicated. It is considered primarily a monosymptomatic hypochondriacal psychosis and has been associated with schizophrenia, obsessional states, bipolar disorder, depression, and anxiety disorders. Delusions of parasitosis occur primarily in white middle-aged or older women, although the condition has been reported in all age groups and in men.

Savely et al[1] introduced the term Morgellon disease to describe a condition characterized by fibers attached to the skin. The entity appears to be little more than a new designation for delusions of parasitosis. Koblenzer[2] and Waddell and Burke[3] have discussed the utility of the term, with Murase et al[4] finding the term useful for building a therapeutic alliance with patients with delusions of parasitosis. The Centers for Disease Control and Prevention is currently investigating Morgellon disease.[5]

William Harvey[6] of the Morgellons Research Foundation Medical Advisory Board states the following:

"All patients with Morgellons carry elevated laboratory proinflammatory markers, elevated insulin levels, and verifiable serologic evidence of 3 bacterial pathogens. They also show easily found physical markers such as peripheral neuropathy, delayed capillary refill, abnormal Romberg’s sign, decreased body temperature, and tachycardia. Most importantly they will improve, and most recover on antibiotics directed at the above pathogens."

The author of this article has not found reliable data to back up William Harvey's claims, but they are included here to comprehensively address this issue.[7]

Walling and Swick[8] suggest abandoning 3 the diagnostic terms trichotillomania, delusions of parasitosis, and neurotic excoriation, which they believe have become barriers to treatment. Instead, they suggest using the alternative patient-centered nomenclature of neuromechanical alopecia, pseudoparasitic dysesthesia, and (simply) excoriation.

It is important to note that many patients with psychopathology complain of delusions of parasitosis, but the coexistence of delusions of parasitosis and another condition, the author thinks, is independent of pure delusions of parasitosis without other symptoms.[9, 10]

One study of 47 patients reported that those noting bugs appeared to be more likely to be diagnosed with of delusional disorder or to have a medical diagnosis, as opposed to those noting fibers, who were more likely deemed to possess a somatoform disorder. Patients referred to a medical setting for delusions of parasitosis were 300 times more likely to require a physician to engage the hospital's legal counsel versus other patients in the same clinical setting.[11]

European researchers reported a series of 148 delusions of parasitosis patients. None of the patients possessed genuine infestation, as was shown by thorough examinations. Thirty-five percent of the patients believed themselves to be parasite infested. Most patients in this series noted a significant number of other living or inanimate (17%) pathogenic agents. Seventy-one (48%) of the 148 patients presented to doctors with “proof” of their infestations. These specimens were, for the most part, skin bits or hair and rarely insects. Only a few of these insects were anthropophilic or of human pathogenicity. No insects could be linked to the clinical presentations.[12]

Two comprehensive reviews in 2013 reiterated the necessity for clinicians to establish a therapeutic alliance with patients due to the challenges of treating a condition that a clinician might think is psychological in nature while the patient is convinced it is real and physical.[13, 14]

To help the patient a strong theraputic alliance must be established with the patient.[15]

Pathophysiology

The cause of delusions of parasitosis is unknown. It appears related to neurochemical pathology. This concept is underlined by its induction by psychoactive agents (eg, amphetamines, cocaine, and methylphenidate) and its coincidence with depression, schizophrenia, social isolation, and sensory impairment. Some reports have linked delusions of parasitosis to hyperthyroidism, which was deemed a secondary type of delusions of parasitosis, because it resolved with pimozide therapy and thyroid medications.

Epidemiology

Frequency

The exact prevalence of delusions of parasitosis is unknown.

Mortality/Morbidity

The literature includes one report of suicide in a 40-year-old man with delusions of parasitosis.[16]

Race-, sex-, and age-related demographics

Delusions of parasitosis appear to be more common in whites than in people of other races.

Delusions of parasitosis occur primarily in white middle-aged or older women, although the condition has been reported in all age groups and in men. The female-to-male ratio is approximately 2:1. More specifically, this ratio is 1:1 in people younger than 50 years and 3:1 in those older than 50 years.[17, 18]

 

History

Patients must be queried about their symptoms, the duration of symptoms, and their belief about the etiology. Notably, Goddard[19] has described a seasonality to delusions of parasitosis, and Vila-Rodriguez et al discuss the facilitation of delusions of parasitosis resulting from Internet-based dissemination of the condition.[20]

The diagnosis and treatment of delusions of parasitosis (DoP) can be an involved clinical activity. Patients with DoP can resist suggestions that their condition is psychiatric rather than physical and refuse referrals for psychiatric care. In fact, in 35% of patients, the belief of infestation is unshakable.[21] In approximately 12% of patients, the delusion of infestation is shared by a significant other. This phenomenon is known as folie à deux (eg, craziness for 2) or folie partagé (ie, shared delusions). Variations in this are the conviction that a child, a spouse, or a pet is infested.

The condition of DoP is a monosymptomatic psychosis, a type of psychopathology relatively distinct from the remainder of the personality. If the condition has a defined pathologic or external cause (eg, scabies), it is not truly delusions of parasitosis. In investigating the history of a patient with such suspected delusions, other causes of itch must be investigated. To diagnose this condition, true infestations (eg, scabies), pediculosis, and primary systemic causes of pruritus must be excluded.[22] Examples include hepatitis, HIV infection, dermatitis herpetiformis, thyroid disease, anemia, renal dysfunction, neurologic dysfunction, and lymphoma.

Delusions of parasitosis are distinct from formication. Formication involves the cutaneous sensation of crawling, biting, and stinging. Formication does not involve the fixed conception that skin sensations are induced by parasites. Patients with this condition can accept proof that they do not have an infestation. Many cases of formication remain idiopathic.

The diagnosis of DoP should be made carefully. Iatrogenic delusional parasitosis, a case of physician-patient folie a deux, has been noted in which a physician made the diagnosis of delusions of parasitosis that was then carried in the medical record, although the patient in fact did not have DoP or actual infestation.[23]

Delusions of parasitosis can occur in isolation on the eyelids, which can result in blindness.[24]  It can also present as a belief that the patient has a disseminated fungal infestation. Authors estimated that 1% of patients with DoP may believed that they are infected with fungi.[25]  

Mimics of delusions of parasitosis

Other forms of psychiatric illness can mimic delusions of parasitosis. Such psychiatric illnesses are accompanied by signs of mental illness. Delusional parasitosis can be the presenting feature of dementia, in which case the delusions of parasitosis is actually secondary.

For example, patients with schizophrenia may think they are being attacked by insects as a manifestation of their paranoia.

A type of severe depression termed psychotic depression may cause the patient to believe he or she is contaminated or "dirty" because of insect infestation. Such a patient may have a depressed mood and a sense of helplessness, hopelessness, worthlessness, or excessive guilt. Often, these feelings are obvious at clinical presentation.[26]

Drug-induced delusions of parasitosis have been reported during treatment for Parkinson disease.[27] Gabapentin-induced delusions of parasitosis has been noted.[28]

Steinert and Studemund[29] reported a 45-year-old man who did not have a history of psychological pathology, who, after ingesting ciprofloxacin to treat an infection, was overcome with acute delusional parasitosis. He stopped taking the ciprofloxacin, and the delusions of parasitosis resolved altogether without utilization of an antipsychotic agent. Tran et al reported a patient who had delusions of parasitosis after receiving a therapeutic dose of mefloquine,[30] and Krauseneck and Soyka reported an association of delusions of parasitosis with pemoline drug therapy.[31]

Cases in which an etiology is defined are best classified as secondary delusions of parasitosis.

Guarneri et al[32] noted a patient who was thought to have delusions of parasitosis but who, in fact, had infestation with Limothrips cerealium; they termed the condition pseudo-delusory syndrome (ie, infestation with an uncommon insect).

Ghaffari-Nejad and Toofani[33] noted a case of secondary delusions of parasitosis in a patient with major depressive disorder who had delusions of oral parasitosis; the patient sensed lizards and small organisms in her mouth.[34]

Physical

Patients with delusions of parasitosis create their rash. They can present with no findings, erosions or ulcers with or without crusts or prurigo nodularis. They may evidence a dermatitis related to attempted treatments, which may include irritating or corrosive cleansers or harsh abrasive devices. Delusions of parasitosis involving the eyelids has been reported.[35]

Laboratory Studies

No laboratory test can help in diagnosing delusions of parasitosis; however, laboratory tests can help identify other diseases that can mimic delusions of parasitosis. Note the following:

Imaging Studies

Huber et al found striatal lesions in patients with secondary delusions of parasitosis, but not in cases of primary delusions of parasitosis.[36] In rare cases, neurologic impairment (eg, tumors, neuritis, multiple sclerosis) can mimic the symptoms of delusions of parasitosis. Causes of such impairment should be excluded with MRI or CT scanning if they are strongly suspected on the basis of the clinical findings.

Histologic Findings

Delusions of parasitosis have no specific histologic findings. All skin changes are secondary to rubbing, scratching, picking, or other treatment attempts.

Because patients who have delusions of parasitosis are having delusions, performing biopsies on them is not useful because any finding, even if negative for parasites, will not affect the delusion.[37]

Medical Care

In 2014, an article on delusions of parasitosis stressed the need of the physician to establish a therapeutic alliance with patients suffering from the condition. Without this alliance it is difficult to convince patients to take the necessary medications. The first meeting with a patient with DP can set the tone for all subsequent encounters.[38]

Another article states that the patient's autonomy must be respected in all encounters.

The physician must provide provide full information regarding the treatment plan and seek consent before starting treatment or asking the patient to seek a psychiatric referral.[39]

There has been an increase in combined psychiatric/dermatologic approaches to treating delusions of parasitosis, using a multidisciplinary approach with dermatologists working with psychiatrists and others. One clinic in Singapore used this approach and noted that delusions of parasitosis was the most common psychophysiologic disorder. The study noted that 20% of patients had psychiatric disorders underlying their skin problems and that trichotillomania and dermatitis artefacta were also observed.[12]

The only clear method to clear the delusion that underlies delusions of parasitosis is the administration of psychotropic medications. However, the condition can remit on its own. If the sensation of itch is related to some actual disease or substance use rather than a monosymptomatic hypochondriacal psychosis, the disease can be treated, or the substance inducing the sensation can be eliminated.

It is vitally important that the practitioner does not "use the delusion" to encourage the patient to accept certain treatments. While getting the patient to take a medication, such as risperidone, may help the condition, telling them that it is a medication that "kills the parasites" reinforces and validates the delusion. Even giving the patient a course of topical permethrin "just in case" may strengthen the delusion and make it that much more difficult later on. Every delusions of parasitosis patient can recount the visit on which his or her suspicions of infestation were "confirmed."

Serotonergic antidepressants may have a role in the treatment of these patients.[40, 41]

Reichenberg et al[42] reported on a patient whose delusions of parasitosis was cured overnight by having him stop taking cetirizine and doxepin (25 mg), as well as any over-the-counter medications.

Rocha and Hara[43] reported that aripiprazole at 15 mg for 8 weeks and then 7.5 mg/d was effective for delusions of parasitosis treatment. They stated:

Aripiprazole has a unique pharmacologic profile that is different from other atypical antipsychotic drugs. It is considered a partial dopaminergic agonist acting on both postsynaptic dopamine D2 receptors and presynaptic autoreceptors. It acts as a weak stimulator (so-called “partial” agonist) at dopamine D2 receptors, with the potential for exerting either antagonistic (inhibitory) or agonistic (stimulating) effects, depending on the sensitivity of the receptors and availability of dopamine, its natural agonist in the brain. In addition, aripiprazole displays partial agonism at serotonin (1A) receptors and antagonism at serotonin (2A) receptors.

Secondary delusional parasitosis was treated successfully with the combination of citalopram and clozapine. What relevance this has for treating primary delusions of parasitosis is unclear. A middle-aged woman treated with extended-release mixed amphetamine salts developed secondary delusions of parasitosis, which resolved with stopping the medication, underlying the need to assess medication usage before making a diagnosis of delusions of parasitosis.

Ladizinski et al also report that aripiprazole may be a useful treatment for delusions of parasitosis.[44]

Szepietowski et al[45] sent out 172 specially designed questionnaires to dermatologists regarding delusions of parasitosis patients; 118 responded. The questions and resulting percentages are as follows:

Consultations

A psychiatrist should be consulted if the dermatologist cannot or will not prescribe the necessary medications. Most patients with delusions of parasitosis are reluctant to see a psychiatrist, and the dermatologist may be more successful in giving the referral if they have gained the patient's trust after several clinic visits instead of immediately after meeting the patient.

Medication Summary

The current treatment of choice is risperidone[46, 47] or olanzapine.[48, 49, 50] The older treatment of choice is pimozide.[51] Several more recent articles have suggested other psychiatric medications can be used to treat delusions of parasitosis, including escitalopram (Lexapro, Forest Pharmaceuticals; New York, NY)[10, 52] and aripiprazole.[53]

The most common adverse effects of pimozide are extrapyramidal symptoms, including stiffness and, occasionally, a special inner sense of restlessness called akathisia. Effective treatment of such extrapyramidal reactions includes benztropine 1-2 mg up to 4 times daily as needed or diphenhydramine 25 mg 3 times daily.

Risperidone (Risperdal)

Clinical Context:  Binds to dopamine D2 receptor with 20 times lower affinity than for 5-HT2 receptor. Improves negative symptoms of psychoses and reduces incidence of extrapyramidal adverse effects.

Olanzapine (Zyprexa)

Clinical Context:  May inhibit serotonin, muscarinic and dopamine effects.

Pimozide (Orap)

Clinical Context:  Antipsychotic of the diphenylbutylpiperidine class. Used to treat delusions of parasitosis and Tourette disorder.

Class Summary

Used to treat psychoses.

Further Outpatient Care

After medication has cleared the delusions of parasitosis, the agent 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 delusions of parasitosis are not treated, scarring can result. The patient's entire life and family may be disrupted by their distress and attempts at treatment.

Therapy for delusions of parasitosis 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 al[54] noted an incidence of camphor-related, self-inflicted keratoconjunctivitis secondary to delusions of parasitosis.

Prognosis

Many patients with delusions of parasitosis 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 delusions of parasitosis.

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 patient education resources, see the Mental Health and Behavior Center.

Author

Bettina E Bernstein, DO, Distinguished Fellow, American Academy of Child and Adolescent Psychiatry; Distinguished Fellow, American Psychiatric Association; Clinical Assistant Professor of Neurosciences and Psychiatry, Philadelphia College of Osteopathic Medicine; Clinical Affiliate Medical Staff, Department of Child and Adolescent Psychiatry, Children's Hospital of Philadelphia; Consultant to Gemma Services, Private Practice; Consultant PMHCC/CBH at Family Court, Philadelphia

Disclosure: Nothing to disclose.

Specialty Editors

David F Butler, MD, Former Section Chief of Dermatology, Central Texas Veterans Healthcare System; Professor of Dermatology, Texas A&M University College of Medicine; Founding Chair, Department of Dermatology, Scott and White Clinic

Disclosure: Nothing to disclose.

Chief Editor

Glen L Xiong, MD, Associate Clinical Professor, Department of Psychiatry and Behavioral Sciences, Department of Internal Medicine, University of California, Davis, School of Medicine; Medical Director, Sacramento County Mental Health Treatment Center

Disclosure: Serve(d) as a director, officer, partner, employee, advisor, consultant or trustee for: Doctor On Demand<br/>Received income in an amount equal to or greater than $250 from: Blue Cross Blue Shield Federal Employee Program<br/>Received royalty from Lippincott Williams & Wilkins for book editor; Received grant/research funds from National Alliance for Research in Schizophrenia and Depression for independent contractor; Received consulting fee from Blue Cross Blue Shield Association for consulting. for: Received book royalty from American Psychiatric Publishing Inc.

Additional Contributors

Franklin Flowers, MD, Department of Dermatology, Professor Emeritus Affiliate Associate Professor of Pathology, University of Florida College of Medicine

Disclosure: Nothing to disclose.

Noah S Scheinfeld, JD, MD, FAAD, † Assistant Clinical Professor, Department of Dermatology, Weil Cornell Medical College; Consulting Staff, Department of Dermatology, St Luke's Roosevelt Hospital Center, Beth Israel Medical Center, New York Eye and Ear Infirmary; Assistant Attending Dermatologist, New York Presbyterian Hospital; Assistant Attending Dermatologist, Lenox Hill Hospital, North Shore-LIJ Health System; Private Practice

Disclosure: Nothing to disclose.

References

  1. Shah R, Taylor RE, Bewley A. Exploring the Psychological Profile of Patients with Delusional Infestation. Acta Derm Venereol. 2017 Jan 4. 97 (1):98-101. [View Abstract]
  2. Koblenzer CS. The challenge of Morgellons disease. J Am Acad Dermatol. 2006 Nov. 55(5):920-2. [View Abstract]
  3. Waddell AG, Burke WA. Morgellons disease?. J Am Acad Dermatol. 2006 Nov. 55(5):914-5. [View Abstract]
  4. Murase JE, Wu JJ, Koo J. Morgellons disease: a rapport-enhancing term for delusions of parasitosis. J Am Acad Dermatol. 2006 Nov. 55(5):913-4. [View Abstract]
  5. Laupland KB, Valiquette L. Delusional Infestation. Can J Infect Dis Med Microbiol. 2016. 2016:9091838. [View Abstract]
  6. Harvey WT. Morgellons disease. J Am Acad Dermatol. 2007 Apr. 56(4):705-6. [View Abstract]
  7. Roncati L, Piscioli F. Morgellons Disease: Truth & Belief. Ann Dermatol. 2018 Jun. 30 (3):361-362. [View Abstract]
  8. Walling HW, Swick BL. Psychocutaneous syndromes: a call for revised nomenclature. Clin Exp Dermatol. 2007 May. 32(3):317-9. [View Abstract]
  9. Hylwa SA, Foster AA, Bury JE, Davis MD, Pittelkow MR, Bostwick JM. Delusional infestation is typically comorbid with other psychiatric diagnoses: review of 54 patients receiving psychiatric evaluation at Mayo Clinic. Psychosomatics. 2012 May. 53(3):258-65. [View Abstract]
  10. Fellner MJ. New findings in delusions of parasitosis. Skinmed. 2012 Mar-Apr. 10(2):72-4. [View Abstract]
  11. Reichenberg JS, Magid M, Jesser CA, Hall CS. Patients labeled with delusions of parasitosis compose a heterogenous group: a retrospective study from a referral center. J Am Acad Dermatol. 2013 Jan. 68(1):41-6, 46.e1-2. [View Abstract]
  12. Freudenmann RW, Lepping P, Huber M, et al. Delusional infestation and the specimen sign: a European multicentre study in 148 consecutive cases. Br J Dermatol. 2012 Aug. 167(2):247-51. [View Abstract]
  13. Levin EC, Gieler U. Delusions of parasitosis. Semin Cutan Med Surg. 2013 Jun. 32(2):73-7. [View Abstract]
  14. Heller MM, Wong JW, Lee ES, Ladizinski B, Grau M, Howard JL, et al. Delusional infestations: clinical presentation, diagnosis and treatment. Int J Dermatol. 2013 Jul. 52(7):775-83. [View Abstract]
  15. Patel V, Koo JY. Delusions of parasitosis; suggested dialogue between dermatologist and patient. J Dermatolog Treat. 2015 Oct. 26(5):456-60. [View Abstract]
  16. Monk BE, Rao YJ. Delusions of parasitosis with fatal outcome. Clin Exp Dermatol. 1994 Jul. 19(4):341-2. [View Abstract]
  17. Aw DC, Thong JY, Chan HL. Delusional parasitosis: case series of 8 patients and review of the literature. Ann Acad Med Singapore. 2004 Jan. 33(1):89-94. [View Abstract]
  18. Bouree P, Benattar B, Perivier S. [Ekbom syndrome or delusional parasitosis]. Rev Prat. 2007 Mar 31. 57(6):585-9. [View Abstract]
  19. Goddard J. Seasonality of delusions of parasitosis. J Agromedicine. 2003. 9(1):23-6. [View Abstract]
  20. Vila-Rodriguez F, Macewan BG. Delusional parasitosis facilitated by web-based dissemination. Am J Psychiatry. 2008 Dec. 165(12):1612. [View Abstract]
  21. Edison KE, Slaughter JR, Hall RD. Psychogenic parasitosis: a therapeutic challenge. Mo Med. 2007 Mar-Apr. 104(2):132-7; quiz 137-8. [View Abstract]
  22. Le L, Gonski PN. Delusional parasitosis mimicking cutaneous infestation in elderly patients. Med J Aust. 2003 Aug 18. 179(4):209-10. [View Abstract]
  23. Bury JE, Bostwick JM. Iatrogenic delusional parasitosis: a case of physician-patient folie a deux. Gen Hosp Psychiatry. 2010 Mar-Apr. 32(2):210-2. [View Abstract]
  24. Thakkar A, Ooi KG, Assaad N, Coroneo M. Delusional infestation: are you being bugged?. Clin Ophthalmol. 2015 Jun. 2;9:967-70. [View Abstract]
  25. Gassiep I, Griffin PM. Delusions of disseminated fungosis. Case Rep Infect Dis. 2014. 2014:458028. [View Abstract]
  26. Koo J, Lee CS. Delusions of parasitosis. A dermatologist's guide to diagnosis and treatment. Am J Clin Dermatol. 2001. 2(5):285-90. [View Abstract]
  27. Swick BL, Walling HW. Drug-induced delusions of parasitosis during treatment of Parkinson's disease. J Am Acad Dermatol. 2005 Dec. 53(6):1086-7. [View Abstract]
  28. Lopez PR, Rachael T, Leicht S, Smalligan RD. Gabapentin-induced delusions of parasitosis. South Med J. 2010. 103:711-2. [View Abstract]
  29. Steinert T, Studemund H. Acute delusional parasitosis under treatment with ciprofloxacin. Pharmacopsychiatry. 2006 Jul. 39(4):159-60. [View Abstract]
  30. Tran TM, Browning J, Dell ML. Psychosis with paranoid delusions after a therapeutic dose of mefloquine: a case report. Malar J. 2006 Aug 23. 5:74. [View Abstract]
  31. Krauseneck T, Soyka M. Delusional parasitosis associated with pemoline. Psychopathology. 2005 Mar-Apr. 38(2):103-4. [View Abstract]
  32. Guarneri F, Guarneri C, Mento G, Ioli A. Pseudo-delusory syndrome caused by Limothrips cerealium. Int J Dermatol. 2006 Mar. 45(3):197-9. [View Abstract]
  33. Ghaffari-Nejad A, Toofani K. Delusion of oral parasitosis in a patient with major depressive disorder. Arch Iran Med. 2006 Jan. 9(1):76-7. [View Abstract]
  34. Duggal H, Singh I. Delusional parasitosis as a presenting feature of dementia. J Neuropsychiatry Clin Neurosci. 2010 Winter. 22(1):123.E11-12. [View Abstract]
  35. Trager MJ, Hwang TN, McCulley TJ. Delusions of parasitosis of the eyelids. Ophthal Plast Reconstr Surg. 2008 Jul-Aug. 24(4):317-9. [View Abstract]
  36. Huber M, Karner M, Kirchler E, Lepping P, Freudenmann RW. Striatal lesions in delusional parasitosis revealed by magnetic resonance imaging. Prog Neuropsychopharmacol Biol Psychiatry. 2008 Dec 12. 32(8):1967-71. [View Abstract]
  37. Hylwa SA, Bury JE, Davis MD, Pittelkow M, Bostwick JM. Delusional Infestation, Including Delusions of Parasitosis: Results of Histologic Examination of Skin Biopsy and Patient-Provided Skin Specimens. Arch Dermatol. May 2011. [View Abstract]
  38. Patel V, Koo JY. Delusions of Parasitosis; Suggested Dialogue between Dermatologist and Patient. J Dermatolog Treat. 2014 Dec 9. 1-15. [View Abstract]
  39. Söderfeldt Y, Groß D. Information, consent and treatment of patients with morgellons disease: an ethical perspective. Am J Clin Dermatol. 2014 Apr. 15(2):71-6. [View Abstract]
  40. Scheinfeld N. Delusions of parasitiosis: a case with a review of its course and treatment. Skinmed. 2003 Nov-Dec. 2(6):376-8. [View Abstract]
  41. Wenning MT, Davy LE, Catalano G, Catalano MC. Atypical antipsychotics in the treatment of delusional parasitosis. Ann Clin Psychiatry. 2003 Sep-Dec. 15(3-4):233-9. [View Abstract]
  42. Reichenberg JS, Magid M, Drage LA. A cure for delusions of parasitosis. J Eur Acad Dermatol Venereol. 2007 Nov. 21(10):1423-4. [View Abstract]
  43. Rocha FL, Hara C. Aripiprazole in delusional parasitosis: Case report. Prog Neuropsychopharmacol Biol Psychiatry. 2007 Apr 13. 31(3):784-6. [View Abstract]
  44. Ladizinski B, Busse KL, Bhutani T, Koo JY. Aripiprazole as a viable alternative for treating delusions of parasitosis. J Drugs Dermatol. Dec 2010. 9:1531-2. [View Abstract]
  45. Szepietowski JC, Salomon J, Hrehorow E, Pacan P, Zalewska A, Sysa-Jedrzejowska A. Delusional parasitosis in dermatological practice. J Eur Acad Dermatol Venereol. 2007 Apr. 21(4):462-5. [View Abstract]
  46. Elmer KB, George RM, Peterson K. Therapeutic update: use of risperidone for the treatment of monosymptomatic hypochondriacal psychosis. J Am Acad Dermatol. 2000 Oct. 43(4):683-6. [View Abstract]
  47. Friedmann AC, Ekeowa-Anderson A, Taylor R, Bewley A. Delusional parasitosis presenting as folie à trois: successful treatment with risperidone. Br J Dermatol. 2006 Oct. 155(4):841-2. [View Abstract]
  48. Meehan WJ, Badreshia S, Mackley CL. Successful treatment of delusions of parasitosis with olanzapine. Arch Dermatol. 2006 Mar. 142(3):352-5. [View Abstract]
  49. Freudenmann RW, Schönfeldt-Lecuona C. Delusional parasitosis: treatment with atypical antipsychotics. Ann Acad Med Singapore. 2005 Jan. 34(1):141-2; author reply 142. [View Abstract]
  50. Atilganoglu U, Ugurad I, Arikan M, Ergun SS. Monosymptomatic hypochondriacal psychosis presenting with recurrent oral mucosal ulcers and multiple skin lesions responding to olanzapine treatment. Int J Dermatol. 2006 Oct. 45(10):1189-92. [View Abstract]
  51. van Vloten WA. Pimozide: use in dermatology. Dermatol Online J. 2003 Mar. 9(2):3. [View Abstract]
  52. Fellner MJ, Majeed MH. Tales of bugs, delusions of parasitosis, and what to do. Clin Dermatol. 2009 Jan-Feb. 27(1):135-8. [View Abstract]
  53. Bennassar A, Guilabert A, Alsina M, Pintor L, Mascaro JM Jr. Treatment of delusional parasitosis with aripiprazole. Arch Dermatol. 2009 Apr. 145(4):500-1. [View Abstract]
  54. Lim GC, Chen YF, Liu L, Huang SC, Lin KK, Hsiao CH. Camphor-related self-inflicted keratoconjunctivitis complicating delusions of parasitosis. Cornea. 2006 Dec. 25(10):1254-6. [View Abstract]
  55. Gee SN, Zakhary L, Keuthen N, Kroshinsky D, Kimball AB. A survey assessment of the recognition and treatment of psychocutaneous disorders in the outpatient dermatology setting: how prepared are we?. J Am Acad Dermatol. 2013 Jan. 68(1):47-52. [View Abstract]