A clinical paradigm of delusions of parasitosis

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  • ing the perception of formication was repeatedlyindicated to the patient. With counseling, the patientwas able to identify reasons for staying alive and asafety plan in the event of further suicidal ideationwas put in place, including her daughter in a visit aspart of her solid support system. The patient wasreferred to her primary care physician to rule out anyorganic causes that could contribute to her delusion.

    Funding sources: None.

    Conflicts of interest: None declared.

    Reprint requests: Francisco A. Tausk, MD, Departments of

    Dermatology and Psychiatry, University of Rochester School of

    Medicine and Dentistry, 601 Elmwood Ave, Box 697, Rochester,

    NY 14642. E-mail: Francisco_Tausk@URMC.Rochester.edu.

    J Am Acad Dermatol 2008;59:698-704.


    2008 by the American Academy of Dermatology, Inc.doi:10.1016/j.jaad.2008.06.033


    A clinical paradigm of d

    Andrea Sandoz, MD,a Matteo LoPiccolo, BS,b Dan

    Rochester, New York; and Haywa

    Dermatologists frequently encounter patientswith cutaneous lesions that are the result ofor that are seriously worsened by self-inju-

    rious behavior. In this manner, it is common forpatients who experience significant pruritus fromvarious etiologies to damage their skin, which pro-duces secondary lesions, such as excoriations andulcerations. It is difficult to establish if the pruriticexperience is not in some cases preceded byscratching. Less frequently, subjects perceive theurge to manipulate a skin lesion for different subjec-tive reasons and lack the impulse control to preventinjuring their skin, such as seen in patients with acneexcoriee, neurotic excoriations, and prurigo nodu-laris, among others. Similar self-injuries are seen insubjects who abuse recreational drugs, such as am-phetamines or marijuana. Relatively infrequently,dermatologists are confronted with patients whohave the conviction of suffering from a parasiticinfestation; these patients pick at their skin in aneffort to extract material believed by the subject to bea living organism. The Diagnostic and StatisticalManual of Mental Disorders specifically includes thiscondition as a primary delusional disorder.1,2

    CASE REPORTSPatient 1

    A 54-year-old female presented to theDermatology Outpatient Center at the University ofRochester complaining of a 5-year history of gener-alized formication, which she attributed to insectslocalized beneath her skin. She reportedly engagedin skin picking in an attempt to rid herself of the

    From the Departments of Psychiatry and Dermatology,a University

    of Rochester School of Medicine and Dentistry,b Rochester; the

    Multicultural Psychotherapy Training and Research Institutec

    and La Familia Childrens Day Treatment,d Hayward; and the

    School of Graduate Psychology,e New College of California,

    San Francisco.S & OPINION

    elusions of parasitosis

    iel Kusnir, MD,c,d,e and Francisco A. Tausk, MDa

    rd and San Francisco, California

    infestation, hoping that the insects would exit herbody and provide relief from her symptoms. Thepatient became guarded and hostile when ques-tioned further about the delusional belief and pro-duced a bag containing a small insect that shebelieved originated from her body. The patient alsoexperienced severe sleep disturbance, loss of appe-tite, and a weight loss of more than 30 pounds. Hermedical history included a psychiatric hospitaliza-tion for delusion of parasitosis (DP) 5 years earlierwhen she was treated with olanzapine, which shediscontinued because of a significant weight gainsecondary to the medication. Her primary care phy-sician recently had referred her to a psychiatrist; sherefused to comply.

    A physical exam revealed numerous excoriationsand ulcerations with erythematous borders presentprimarily on her arms and upper back. Significanthypopigmented, hypotrophic scarring was also ob-served diffusely throughout her back. A large scarwas the result of laying against a stove in an attemptto provide an exit route for the parasites by burningher back. In addition to the firm delusion of sufferinga parasitosis, the psychiatric exam revealed inter-mittent feelings of helplessness, hopelessness, agita-tion, and suicidal ideation.

    Laboratory tests revealed a normal completeblood cell count (CBC) with differential, a normalcomplete chemistry panel, and a negative immuno-globulin G (IgG) and IgM Lyme antibody titer. Thepatient had the firm belief that she had Lyme disease,so testing was performed to overcome her convic-tion, build trust, and improve the relationship be-tween the patient and her physician.

    Upon the subsequent three visits, the patientcontinually refused to begin a trial of antipsychoticsand demanded additional laboratory and skin test-ing. While the testing was performed, the proposi-tion that the scratching and picking on the skin mayactivate and harm nerve endings enhancing or caus-

  • During her fifth visit, the patient began to considerthe possibility that her peripheral cutaneous nerveendings could be playing a role in her disease andbe enhancing her discomfort, and she agreed tobegin a course of aripiprazole. She was initiated at adose of 2 mg/day, which was subsequently slowlytitrated up to a total of 20 mg/day. After 2 to 3 weeks,she reported improvement of formication and thepain sensation changed from a level of 10 (on a 0-10scale, with 0 being no sensation and 10 being theworst sensation possible) to a 2 to 3. With continuedtreatment, her delusional beliefs and her sleep,mood, suicidal ideation, and anxiety continued todecrease in severity and ultimately disappearedcompletely. One year after beginning aripiprazole,she is currently maintained on a dose of 10 mg/day.The patient continues to be well, her skin lesionshave healed, and she feels that her goals of treatmenthave been attained and that the management of hersymptoms is adequate.

    Patient 2A 54-year-old female consulted the Department

    of Dermatology at the University of Rochestercomplaining of a 7-year history of a cutaneousburning sensation and the protrusion of coloredfibers from her skin, which she felt were caused byskin parasites. She picked at the fibers repeatedly inan effort to rid herself of the infestation. Previoustherapies attempted for her condition included nu-merous topical corticosteroids and permethrin. Hermedical history included severe anxiety and depres-sion, for which she was under the care of a psycho-therapist and a psychiatrist who medicated her withclonazepam. Therapy was also attempted unsuc-cessfully in the past with selective serotonin reup-take inhibitors.

    A physical exam revealed the presence of numer-ous excoriations, ulcerations, and scars, primarily onher extremities. The patient was anxious, tearful, andsuffered from logorrhea. She brought fibers that shefound on her skin, and believed that she hadMorgellons disease. During the initial visit, the pos-sible background of her disease was discussedextensively with the patient, and the notion thatcutaneous nerves could be playing a role in theprocess was introduced. Despite this, however, herdelusion could not be reduced. At that point, thepatient was told that she would continue to befollowed in the psychocutaneous clinic in conjunc-tion with a psychiatrist. The latter resulted in thedevelopment of agitation on the part of the patient,who became guarded and felt that the dermatologistdid not adhere to her theory of disease. The patient

    J AM ACAD DERMATOLVOLUME 59, NUMBER 4did not return for the follow-up visit.DISCUSSIONMonosymptomatic delusional disorders are char-

    acterized by the presence of delusions, hallucina-tions, or formal thought disorder. Delusions are fixedfalse beliefs that patients hold with unshakeableconviction, which are not grounded on a largercultural, ethnic, or religious set of beliefs. Patientswho manifest the circumscribed false belief of beinginfested with parasites constitute the diagnosis of DP.This is frequently the only overt manifestation of thesubjects psychosis; therefore, these patients mostoften present to dermatologists and entomologistsrather than psychiatrists. Their refusal to see a mentalhealth provider poses a very difficult task for thedermatologist, and the presence or sharing of thisbelief by a member of his immediate surroundings( folie a` deux, occurring in 12 to 18% of cases) posesadditional complications.1-3

    PatientswithDP frequently present to the clinicianin an anxious, ruminative, overwhelmed state, with ahistory of visits to multiple physicians without satis-faction.2 In addition to proffering a long and detailedhistory that includes visual and/or tactile hallucina-tions of the organisms, the patient also frequentlyprovides evidence of the parasitic infection in theform of clothing lint, fibers, skin crusts, or otherdebris, which are misinterpreted as entire organisms,body parts, larvae, or ova. Skin manifestations can bequite variable, ranging from mild excoriations tolarge ulcers. These usually reflect attempts by thepatient to free themselves of the perceived infestationby creating self-inflicted wounds. This is a mono-symptomatic delusional disorder; therefore, somepatients have a well organized train of thought andnormal outward appearance, resulting in the convic-tion by those surrounding them that the subject has atrue infestation. The delusion becomes apparent tothe physician, however, when the subject is ques-tioned about the condition.

    The literature suggests that there is a femaleto male predominance of DP ranging from 1.5:14 to2:1.2,3,5,6 The mean age of symptom onset appears tobe in the sixth decade of life, but ranges from themiddle teenage years to the late eighties.2,7,8 Inaddition, comorbidity with or family history of majordepression or bipolar disorder is not uncommon inthese patients.

    The treatment of DP poses several challenges forthe physician. The false belief that an infestingorganism is causing the skin sensations and lesionsplaces the cause of discomfort in the skin rather thanin the mind, and commonly deters the patient fromaccepting mental health treatment, and because of

    Sandoz et al 699this a referral for a psychiatric evaluation is usually

  • refused. Patients often become frustratedwith feelingas though their claims of suffering over a skin disor-der are invalidated, lose trust in their dermatologistand/or primary care provider, and resort to doctorhopping in an effort to find a provider who willendorse their delusions.2,7 The time demands in-volved with a mental health referral, the difficulty incoordinating care among several providers, a phys-icians unfamiliarity with the disorder, and thepatients potentially limited understanding of psy-chotherapeutic and pharmacologic interventionsprovide further barriers to successful treatment. Theinability to obtain effective therapy may generatefurther suffering and anxiety for the patient and oftenleads to injurious behavior or suicidal ideation.2,5,9

    Pimozide2 (Orap;GatePharmaceuticals, Sellersville,PA), a first-generation neuroleptic, though rarelyprescribed by psychiatrists, has traditionally beenthe drug of choice for treating DP and Tourettesyndrome. While a metaanalysis suggests that pim-ozide induces a full remission rate of 50%,3 recentstudies reported a remission rate of 33% 5 weeksafter prescribing pimozide, and 28% upon a follow-up averaging 5.1 years,4 and up to 90% of patientsexperiencing partial or complete recovery.10,11

    Pimozide is reported to have a powerful antipruriticaction, which is believed to be caused by its effect onopiod pathways.

    As with all first-generation neuroleptics, there areseveral drawbacks to using this drug10; central ner-vous system side effects include frequent com-plications with extra pyramidal syndrome, which ischaracterized by early symptoms of Parkinsonism,akathisia, and acute dystonia, later followed bytardive dyskinesia. Particular cardiac effects of pim-ozide including QTc prolongation, T wave changes,and the appearance of U waves, which requireregular electrocardiographic monitoring. The inter-action of pimozide with the macrolide antibioticsfurther precipitates these cardiac side effects. Thisinteraction occurs relatively often as many patientswith DP are frequently prescribed antibiotics in orderto treat secondary infections of their excoriations. Inspite of the reported effectiveness of pimozide, itsside effect profile makes it potentially problematic asa treatment for DP.

    The development of atypical antipsychotics, witha marked lower incidence of extrapiramidal syn-drome (EPS), has modified the therapy of psychosisandmostly replaced the use of classic antipsychotics.Because of the paucity of reports of patients with DPtreated with atypical antipsychotics, such as olanza-pine, risperidone, quetiapine, and aripiprazole, theirside effect profile is based primarily on the well

    700 Sandoz et aldocumented experience in their use in the therapy ofpatients suffering from schizophrenia, other psycho-ses, and bipolar disorder.12-20

    The critical issue in deciding which medicationto use in the treatment of DP is the consideration ofside effects (Table I).

    Extrapiramidal syndromeWith the advent of atypical antipsychotics, the

    incidence of EPS has decreased, although it is stillpresent, particularly in the elderly and in patientsrequiring high dosages of these medications. Theappearance of EPS is dose dependent, in part,because of the saturation of dopamine receptors.21

    EPS can be seen with relative frequency in subjectsreceiving high doses of risperidone, infrequently inthose receiving ziprasidone or aripiprazole, and veryrarely with olanzapine or quetiapine, the latter beingthe drug of choice in patients that are prone todevelop EPS. Patients treated with aripiprazole maydevelop akathisia, characterized by a sense of dis-comfort, severe anxiety, motor restlessness, andincreased muscle tone. These symptoms may betreated with benzodiazepines and/or adrenergicbeta blockers.14-18

    Metabolic syndromeThe development of weight gain, diabetes, and

    hyperlipidemia is a serious concern in the treatmentof patients with DP. These are frequently seen inpatients treated with olanzapine and clozapine. Theincidence is lower in those receiving quetiapine andrisperidone, and it rarely occurs with ziprasidone oraripiprazole.12,19,22,23

    SedationThis symptom is frequently found in patients that

    are prescribed antipsychotics. Olanzapine, ziprasi-done, and quetiapine have a high sedative potential,whereas patients treatedwith risperidone or aripipra-zole have lower incidence of this side effect.12,15,24,25

    Less frequent side effects include cardiac risk,primarily related to a prolonged QT interval, whichcan be a side effect of ziprasidone. Agranulocytosismay be a complication of clozapine, and requiresclose follow-up in subjects treated with this drug.Because of the life-threatening potential of this drug,the use of clozapine for the treatment of DP is highlydiscouraged. Hyperprolactinemia, characterized bysexual dysfunction, galactorrhea, a decrease in min-...


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