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-eral bone density, and fractures can be seen insubjects treated with risperidone.13 Postural hypoten-sion is frequently seen during treatment with risper-idone or quetiapine. Anticholinergic effects are seenin a dose dependent fashion associated with cloza-

    J AM ACAD DERMATOLOCTOBER 2008pine, olanzapine, and quetiapine. All antipsychotics

  • at the dopamine D2 and serotonin 5HT1A receptors

    J AM ACAD DERMATOL Sandoz et al 701and as a 5HT2A antagonist. These dopamine andserotonin stabilizing properties may be of therapeu-tic value for DP. Although this drugs partial bindingto D2 receptors implies a lower incidence of EPS, thisside effect may be seen in approximately 10% ofpatients treated with high doses of aripiprazole,particularly akathisia20-21,31-33 Table III lists theknown adverse effects of aripiprazole.

    The two index cases reported highlight the needto have a multidisciplinary approach to patientswith DP. Although this becomes very difficult in adermatologists private office, it can easily be at-tained in a hospital setting. The Center for IntegrativeDermatology at the University of Rochester is staffed

    theory had not been readily accepted, and theperception of lack of empathy on the part of thedermatologist. This ultimately resulted in the pa-tients noncompliance. The following approach wasused in the case of patient 1, and may prove to beuseful as a guideline in the management of otherpatients suffering from DP.


    The dermatologist must first approach a patientwith presumed DP by performing a thoroughhave to be prescribed with caution in the elderly, apopulation in which they have been associated withsignificant side effects, such as increased mortalityand risk of thromboembolism.20

    As shown in Table II, most of the publishedexperience in treating patients with DP has beenwith pimozide.10,11 A limited number of reports onthe effectiveness of atypical antipsychotics havebeen published recently, suggesting that some ofthese may be as incisive as pimozide.26,27 In patient1, discussed above, aripiprazole at a dose of 20mg/day was tolerated with minimal side effects andwas effective in inducing and maintaining 1 year ofsymptom remission. This is the fourth report in theliterature of full reduction of the delusions in patientswith DP treated with aripiprazole.28-30 It is too earlyto propose this drug as the treatment of choice, butthe limited results achieved with this medicationprovide evidence that DP patients have respondedfavorably to its administration.

    Aripiprazole (Abilify; Bristol-Meyers Squibb, NewYork, NY), the most recently approved antipsychoticdrug in the United States, is a third-generation partialD2 receptor dopamine antagonist with clear anti-psychotic effects. It is effective, relatively safe, welltolerated, and represents a novel treatment for psy-chotic disorders. Aripiprazole acts as a partial agonist

    Table I. Adverse effects of antipsychotics of potential u

    Antipsychotic EPS Metabolic syndrome Seda

    Pimozide 111 e eRisperidone 11 11 1Ziprasidone 1 1/e 1Olanzapine 1/e 111 1Quetiapine 1/e 11 1Aripiprazole 1 1/e 1

    111, Severe; 11, moderate; 1, mild; 1/e, infrequent; e, absent.ACh, Anticholinergic effects; BP, postural hypotension; EPS, extrapiram

    QT interval.

    VOLUME 59, NUMBER 4by a dermatologist and a part-time psychiatrist in ashared office located in the dermatology outpatientarea. This allows for a seamless transition betweenstrictly dermatologic treatment and psychotherapeu-tic care. Patient 2 exemplifies the need to pace theapproach to the patient whose delusion cannotinitially be reduced. In this case, the acceleratedintroduction of the notion of a combined psychoedermatologic treatment strategy created fear andanxiety in the patient, the notion that her disease

    se in delusion of parasitosis

    tion QT interval Hyper-PRL BP ACh

    11 e 1/e 111 11 11 e

    1 11 1 1/e e1 e e 1/e 11 e e 1 1/e e e 1/e e

    idal syndrome; Hyper-PRL, hyper-prolactinemia; QT interval, prolonged

    Table II. Results of the effect of antipsychotics inthe treatment of patients with delusion ofparasitosis*






    remission No effect

    Pimozide 24 26 0Risperidoney 8 3 0Olanzapine 1 1 2Aripiprazole 4z 0 0Quetiapiney 0 2 1

    *Summary of the number of patients with delusion of parasitosis

    treated with antypsychotics and result of intervention as reported

    in the literature. Adapted and updated from Lepping et al,11 Rocha

    and Hara,28 Kumbier and Hoppner,29 and Dimopoulos et al.30

    ySome of the patients that improved with risperidone andquetiapine received additional psychiatric medications.zThe fourth case with aripiprazole is patient 1 in this report.

  • physical examination and ruling out real infestations.As obvious as this may appear, two out of ninepatients referred to our clinic for treatment of DPduring the last 6 months were suffering from miteinfestations.

    The next step is to assess the level of distortionand rigidity that a patient has regarding the origin ofthe disease and their openness to accept alternativeviews. In this way, the dermatologist can categorizethe subject within a spectrum of disease (under-standing DP in the broad sense). A patients beliefthat the subjective feeling of formication is caused byan infestation may be rooted in an experientialsituation. For example, if members of a patientshousehold have been diagnosed with lice, he or shemay interpret a subsequent crawling feeling assecondary to such infestation. Or, in another case, apatient may erroneously interpret scales, crusts, orfibers as living organisms. We must parse out thesepossibilities before assuming that our patient pre-sents with a real delusion and not a merely equivocalinterpretation of reality. Once a true delusional stateis confirmed, the dermatologist must probe the levelof irreducibility of the ideation. This involves that inthe absence of the objective finding of true parasites(see below), the patient can be guided to question-ing of the conviction by providing alternate possibleetiologies.

    The dermatologist must show interest in theelicited theory of disease, maymirror the expressionsof the patient to show his/her understanding of thepatients concerns, and avoid confronting the patientabout the psychiatric etiology of his or her symptoms.It is important not to reinforce the delusional beliefs;however, one should also avoid taking a completely

    Table III. Adverse effects of aripiprazole

    Relatively common* Rare

    Constipation Parkinson diseaseSedation Tardive dyskinesiay

    Tremor HyperglycemiaHeadache Metabolic syndromeDizziness, orthostatic

    hypotension, nausea,and vomiting

    Neuroleptic malignantsyndromez

    Insomnia HypertensionAkathisia Weight gain

    *Side effects are more frequent in the elderly, who require caution

    when treated with antipsychotics.yRepetitive, involuntary, and purposeless movements.zHyperthermia, change in mental status, diaphoresis, musclerigidity, elevated creatine phosphokinase, and tachycardia.

    Requires emergent evaluation.Unpleasant subjective sensation of restlessness.

    702 Sandoz et alneutral stance that will make the patient guarded.If the patient brings samples, offer to evaluate themunder a microscope and invite the patient to viewthem.Performa full skin examinationand reassure thesubject that no organisms are visible on the patientsbody at the time. One may also include the possibilitythat the lack of visible parasites may be the result of apreviously efficacious treatment.Discuss compassion-ately the patients suffering as a result of the conditionand address the need to intervene to reduce theirstress.

    Treat any open wounds with topical antibioticsand inform thepatient that youwill study their case.It is also important at this time to rule out any organiccause of the patients symptoms that my mimic DP,including nutritional disorders (notably vitamin B12deficiency and pellagra); neurologic disorders, in-cluding brain tumor and temporal lobe epilepsy;substance abuse or withdrawal, endocrine disorders,malignancy, infectious diseases, and cardiovasculardisease. Acute DP has also been reported to followthe administration of prescription drugs.34,35 Beforetreatment, patients with DP require appropriate lab-oratory evaluations2 (Table IV). Performing biopsiesupon request rarely satisfies the patient, who willinsist that they were taken from the wrong sites andcontinue to request additional ones. It is better toavoid them by informing the subjects that theirinfestation will not be visible by histology. Thisinitial visit may take anywhere between 10 and 20minutes.

    Second to fourth visitsDuring the next two to four visits, begin ap-

    proaching the patients psychological suffering. Ifthe patient brings more samples, they should beexamined. In cases where the patient brings up thesubject of Morgellons disease, direct the patient tothe official Morgellons Research FoundationWeb site(www.morgellons.org), where it is stated that one ofthe main manifestations of the disease are psycho-

    Table IV. Suggested laboratory workup of patientswith delusions of parasitosis

    Complete blood cell count with differentialSerum electrolytesGlucoseCreatinine and blood urea nitrogenLiver function testsThyroid functionUrinalysisSerum vitamin B12, folate, and iron levelsElectrocardiogram

    J AM ACAD DERMATOLOCTOBER 2008logical/psychiatric in nature, and highlight the need

  • J AM ACAD DERMATOL Sandoz et al 703to treat them. Try to shift the focus of the patient fromthe fixation on skin lesions to the emotional sufferingthat the subject is experiencing, and the need toalleviate it by pharmacologic interventions.

    Introduce at this time the concept of the existenceof a nerve fiber network in the skin, which becomeshypersensitive, that the feeling of formication doesnot imply live organisms, and that the skin may besending an abnormal signal to the central nervoussystem. At this time, one can introduce the notionthat neuroleptics are required in order to treatthe sensory alterations. If pain or pruritus is pre-sent, present the patient with evidence from theliterature36-40 that antipsychotics are effective in itstreatment.

    It is beneficial to recruit the cooperation of mem-bers of the immediate family as long as they do notshare the delusion. Their inclusion has been shownto be critical in achieving appropriate compliance inpsychotic patients.41

    Continued careIf the attention provided through the above

    approach helps the patient accept combined derma-tologic and psychiatric pharmacotherapy, considerthe possibility of continuing the treatment withoutfurther psychiatric consultation.

    If needed and possible, the psychiatrist can beintroduced to the patient in the general dermatologysuite on the next visit. During this combined session,the psychiatrist should evaluate the patients mentalstatus, comorbidities, and substance abuse. Ideally,the psychiatrist would then prescribe any additionalappropriate medication. Because in most clinicalsettings it is impossible to perform a combined visitthat includes a psychiatrist and a dermatologist, andbecause patients with DP usually will refuse to see apsychiatrist, it is the dermatologist that carries theburden of commencing the treatment. Many times,the patient will agree to visit a psychiatrists officeonly after the delusions are reduced. In many in-stances, once the treatment has been commenced bythe dermatologist, and a strong positive alliance hasbeen established, it may become difficult for thesepatients to reestablish a new trusting relationshipwith another physician (in this case the psychiatrist)for the same problem, and the continuing care underthe direction of the dermatologist may be the moreclinically sound decision.

    Before beginning medication with atypical anti-psychotics, the patients primary care physicianshould be contacted to become aware and involvedin the treatment plan andpossible side effects, such as

    VOLUME 59, NUMBER 4the development of metabolic syndrome. Followingthe recommendations of the consensus developmentconference led by the AmericanDiabetes Associationand American Psychiatric Association,42 patients re-ceiving an antipsychotic agent shouldhavemetabolicparameters screened at baseline and followed byregular monitoring of their body mass index every 4weeks for the first 3 months, and then quarterly withblood pressure, fasting glucose, and fasting lipids. Itis also important to obtain family history of diabetes,obesity, and dyslipidemia.

    In general, the doses of antipsychotic drugs re-quired to control the symptoms of cutaneous delu-sions are, by psychiatric standards, relatively small. Ifaripiprazole is the chosen drug, it should be started inlowdoses, and slowly titrated until a therapeutic levelis achieved. The side effects of this drug are explainedin Table IV. When starting with low doses, activationis often present, generating some insomnia andanxiety. The dermatologist has to be aware of thisand address it with the patient in order to achievecompliance. As the dosages are gradually increased,these side effects generally resolve. Because aripi-prazole is relatively new, long-term effects may notbe available at this time.

    Aripiprazole is metabolized through CYP3A4 andCYP2D6.Drugs that induceCYP3A4such as carbam-azepineloweraripiprazole levels,whereas inhibitorsof CYP3A4 or CYP2D6such as ketoconazole, quin-idine, fluoxetine, or paroxetinemay increase sys-temic levels of aripiprazole. This should be consideredwhen deciding to add concomitant treatment withantidepressants. Antipsychotic effects are rarely at-tained in less than 2 weeks, and 4 to 8 weeks areusually needed to achieve full effectiveness.

    Regular follow-up is needed and can be pre-formed by the dermatologist who may want toreview the treatment with a psychiatrist periodically.

    If aripiprazole was chosen as the initial medica-tion and does not improve the patients condition,consider noncompliance and/or switching to ris-peridone, quetiapine, or a first-generation antipsy-chotic, such as pimozide.

    It is very important to note that on occasion, apatient will refuse any approach except continuoustreatment with antiparasitic drugs, and they maydemand biopsies, become belligerent, and persist intheir delusion without allowing the physician tointroduce any wedge into their unshakeable belief.If the patient is in danger of harm, other psychosocialmeasures may be indicated (eg, reporting the patientto adult protective services, psychiatric emergencyservices, or eventually the police, depending on thelocal regulations for these situations). Otherwise, wehave to be aware of our limitations and know when

    to give up on our stride to serve the patients whorefuse our help.


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    A clinical paradigm of delusions of parasitosisCase reportsPatient 1Patient 2

    DiscussionExtrapiramidal syndromeMetabolic syndromeSedation

    Recommended therapeutic approach to patients who present with delusions of parasitosisFirst visitSecond to fourth visitsContinued care



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