Concurrent Delusions of Ocular Parasitosis and Complex Visual Hallucinations from Charles Bonnet Syndrome Treated Successfully with Aripiprazole in an Elderly Male: A Case Report


Nakiya T Whitfield Pharm D; Anne E Krasniak Pharm D; Hien T Nguyen MD

Perm J 2020;25:20.132 [Full Citation]
E-pub: 12/02/2020


Introduction: Delusional parasitosis (DP) has been described as among the most challenging diagnosis to manage in dermatology and psychiatry literature. Patients with this perplexing and enigmatic condition present potentially to a wide range of specialties including primary or emergency care, dermatology, infectious diseases, neurology, and psychiatry. DP is probably underdiagnosed from patients’ underreporting of symptoms of being infested with parasites, resulting from the associated social stigma. In addition, specialists who most often encounter these patients often possess low familiarity and comfort level in the diagnosis and therapy of this disorder. To our knowledge, we present only the fifth case of delusional parasitosis that was associated with complex visual hallucinations. Both concurrent conditions were treated successfully with aripiprazole. Interestingly, in all of these prior cases including ours, the patients were elderly (age range, 74-95 years). Delusions of ocular parasitosis has been described in fewer than 11 cases. When delusions occur concurrently with hallucinations, the differential diagnosis becomes even more challenging and may include schizophrenia, drug-induced psychosis, Lewy body dementia, and Charles Bonnet syndrome. Our patient’s delusions of ocular parasitosis led to ocular damage and severe visual impairment because of his constant need to extract the parasites from his eyes. We speculate that the subsequent complex visual hallucinations that developed can best be understood as Charles Bonnet syndrome.

Case Presentation: A 78-year-old healthy African American male complained of pests and bugs approximately 2 cm in size that infested the skin of his entire body. He also described the life cycle of these parasites, which jumped onto his eyelids and conjunctiva. He developed functional vision blindness from his unwillingness to open his eyelids as a result of his attempts to block the parasites. He was evaluated by dermatology, infectious diseases, ophthalmology, and psychiatry. All specialists agreed with the diagnosis of DP, and recommended antipsychotic therapy. They consistently dismissed the patient’s symptoms as anything more than psychiatric, so the patient did not follow-up for further assessments or other therapies. Even months after the diagnosis of DP, he developed complex visual hallucinations. He described new visions in vivid detail: inanimate objects (buildings, jackhammers, torches, planes), animals (bears, doves, sharks), shapes (triangles, rectangles, omega, and mason signs). The objects interacted on high-definition landscapes such as oceans. He refused further psychiatric assessment because he felt strongly that the symptoms were infectious in nature and not psychiatric. However, a therapeutic relationship with his geriatrician was established through empathic communications, goal setting, and shared decision making. He even agreed to start treatment with aripiprazole 2 mg because the shared goal was symptom management of the concurrent delusional parasitosis and complex visual hallucinations. The slow titration of aripiprazole to 6 mg led to a 75% reduction in the delusions and hallucinations. He initially declined higher dosages of the aripiprazole because of sedation and personal wariness of medications in general. However, a therapeutic relationship was nurtured based on respect, careful listening, and provision of options. Eventually, he agreed to a higher dosage of aripiprazole and thus titrate antipsychotic therapy that he rejected when prescribed by the dermatology and psychiatry specialists. We attempted to approximate the 15-mg dosage that led to remission of symptoms in previous case reports.


Delusional parasitosis (DP) is an underrecognized and undertreated disorder in which affected individuals have a fixed and false belief that they are infested by vermin, parasites, worms, mites, bacteria, fungus, or other living organisms.1-14 One of the most salient teaching points is the critical importance of a trusting and therapeutic partnership that overcome the initial resistance to all psychiatric care. The utility of aripiprazole as a safer and effective antipsychotic therapy for treatment of concurrent DP and complex visual hallucination (CVH) in the elderly is described as well as the relevance of recognizing concurrent ocular and dermatologic DP.


Presenting Concerns

A 78-year-old African American male complained of an infestation of pests and bugs throughout his body and eyes. A baseline ocular examination revealed chronic severe glaucoma and cataracts. He constantly kept his eyelids closed because he believed this prevented the entry of these pests in their cycle into the aqueous environment of his eyes. The infestation was very burdensome as he spent nearly 2 hours daily upon awakening to vacuum the pests that spilled out of his eyes. Within 7 months of the initial diagnosis of delusional parasitosis, he developed complex visual hallucinations, described in vivid detail that he believed were shown to him like a movie. He conceded that his wife did not visualize these same images nor the pests. He had completed high school and served satisfactorily for several years in the military. He reported sporadic use of marijuana but no other illicit drug use.

On neurological examination, the patient did not have tremor, cogwheel rigidity, bradykinesia, or other symptoms of parkinsonism. Psychological assessment did not reveal other reality or mood disturbances. The patient had a score of 28/30 on his Mini Mental Status Examination but was unable to complete the Montreal Cognitive Assessment test because of his visual impairment. One point was deducted on the Mini Mental Status Examination for the 5-minute 3-word recall, and 1 point for spelling a 5-letter word backwards. His ocular examination on presentation at the onset of his delusional parasitosis included primary open angle glaucoma, iritis, and cataracts. Eventually, he had vision to light perception only, as described in Figure 1.


Figure 1. Ocular examination after diagnosis of delusional parasitosis.

The medical workup of primary and secondary parasitosis and complex visual hallucinations overlapped and required consideration of diverse medical, organic, and neuropsychiatric causes. The normal laboratory tests included those for thyroid, hepatic, chemistries, vitamin 12 and folate, Lyme, syphilis, HIV, blood dyscrasias, and urine drug screen. Brain magnetic resonance testing did not show abnormalities. An electroencephalogram (EEG) was performed and was normal. The differential diagnosis of this patient’s concurrent ocular delusional parasitosis and complex visual hallucinations was very challenging and included a psychotic disorder such as schizophrenia, a drug-induced psychotic disorder such as marijuana psychosis (our patient was advised to stop using the drug but the hallucinations persisted), Lewy body dementia (LBD), and Charles Bonnet syndrome (CBS). Ultimately, the patient’s history, clinical presentation, and neuropsychological examinations did not support the first 3 diagnoses.

The core features of LBD are (1) fluctuating cognitive impairments, (2) recurrent visual hallucinations, (3) spontaneous symptoms of parkinsonism (bradykinesia, tremor, cogwheel rigidity, postural instability), and (4) rapid eye movement sleep behavior disorder.15 The patient’s cognition was normal and he never exhibited any symptoms of parkinsonism even when he was treated with antipsychotic therapy. Thus, further diagnostic testing for LBD such as dopamine transporter imaging and 123 iodine-metaiodobenzylguanidine myocardial scintigraphy were not performed. Apart from the delusions of parasites and complex hallucinations, the patient did not present with any other characteristics of schizophrenia, including disorganized thinking, abnormal motor behavior, or negative symptoms. We considered marijuana psychosis, which is characterized by delusions, hallucinations, dissociation, and disordered chaotic thought processes. However, the patient’s delusions and hallucinations persisted even with marijuana cessation.

We believe that his complex visual hallucinations may be best understood in terms of CBS, which arose from vision impairment resulting from 2 sources. One was his preexisting organic ocular pathology and the second is functional vision blindness from voluntary forced eye closure. Although the medical literature has described acute vision impairment from glaucoma or cataracts leading to CVH in CBS, this patient’s CVH did not develop until he stopped opening his yes to cope with the parasites.

Treatment and Therapeutic Outcomes

A supportive and therapeutic relationship was established with his geriatrician, who acknowledged the patient’s symptoms, emphasized symptom management, and fostered goal setting. Although the patient refused to follow-up with the psychiatrist, the patient ultimately agreed to antipsychotic therapy ordered by his geriatrician. The patient was treated with an initial dose of aripiprazole 2 mg that was slowly titrated to 6 mg daily. Although he admitted wariness to taking medications of any sort, he eventually agreed to titration of the aripiprazole to 10 mg, which achieved further subjective reductions in his complex visual hallucinations. This was achieved by a respectful, empathic, therapeutic relationship and shared decision making (the Discussion section elaborates on the processes used). The improvements in delusions and hallucinations were dramatic by patient’s own estimation of 75% fewer hallucinations including those for jackhammers, torches, planes, lasers, geometric shapes, and buildings. Just as relevant, he was able to open his eyes more than 10 to 15 times per day, which allowed him to visualize his arms, hands, and fingernails for the first time in nearly a year. At this time, he was referred back to ophthalmology for consideration of cataract extraction that the patient vehemently refused unfortunately because of a bad outcome of such surgery in a family member. Interestingly, he reasoned that his enhanced ability to see more things of reality through opening his eyes more was worth the tradeoff that pests could potentially land onto his eyes more.


Delusional Parasitosis

Delusions of parasitosis were first described by the French dermatologist Thibierge in 1894, as the fixed conviction that patients are infested by insects, vermin, worms, or other organic creatures.5

Delusions of parasitosis is a delusional disorder of somatic subtype and is also known as delusions of infestation or Ekbom syndrome.15-17 Characteristic sensations include itching, biting, crawling, and wriggling (formication) at infected sites.1-5 Further patients may describe in great detail the lifecycle of the pests; deliver specimens as proof of their infestation (matchbox sign), which invariably, turns out to be dust, plant or animal fibers, scabs, or skin debris; and report failed drastic measures at home to eliminate the infestation.13-15 Significant disruptions in personal and professional relationships may occur in affected patients. In 10% of cases, there is a shared psychosis with a person in close proximity such as a spouse, and such a relationship is termed folie a deux.4,15,18

The mean age of affected patients with DP is 57 years, and there an approximate 3:1 female to male ratio.17,18 Females have generally longer duration of symptoms.15-17 Further, prior comorbid psychiatric conditions are reportedly in nearly 80% of patients with DP such as depression and anxiety, and 15% of patients with DP have documented illicit drug use.17,18 The true prevalence of delusions of parasitosis is most likely far greater than suggested by the medical literature because of patients’ reluctance to report symptoms, low awareness of this condition in the medical community, and the varied nomenclature describing this condition.16,17 Patients with delusional parasitosis may have recurring presentations to primary and emergency care, dermatology, infectious diseases, psychiatry, and neurology.

Delusional parasitosis may be primary or secondary to diverse underlying organic or psychiatric conditions. These include vitamin B12 deficiency, iron deficiency anemia, renal failure, Hodgkin lymphoma, hypothyroidism, diabetes mellitus, hepatobiliary dysfunction, heart failure, multiple sclerosis, hepatitis, syphilis, stroke, pneumoniae tuberculosis, AIDS, Lyme disease, and substance use (alcohol, cocaine, and amphetamine).2-5 Delusions of parasitosis has been described in patients with strokes involving the right temporal parietal cortex, thalamus, and putamen.19 A case series by the Mayo Clinic also implicated hypercalcemia, fibromyalgia, seizure disorder, and Alzheimer’s disease as possible causes.17 Like most other psychiatric disorders, the pathogenesis of delusional parasitosis is not well understood. There is a theory that delusions of parasitosis may be associated with elevated dopamine levels in the striatum. This is supported by the efficacy of dopamine antagonists in the therapy of DP.2,5,15,17

Ocular Delusional Parasitosis

Ocular DP is defined by delusions of parasites involving the eye. It occurs very rarely, with Meraj in 2011 reporting 6 case reports.11 These patients sustained self-inflicted injuries to the eyes from their mechanical and chemical attempts to remove the parasites.10-12 Ocular damage included periocular excoriations, papillary conjunctivitis, chemosis, conjunctival laceration and chemosis, corneal epithelial toxicity, and stromal ulceration.10-12, 20 Delusions of ocular parasitosis is especially critical to diagnose and manage early because of sight-threatening complications that are possible, especially when patients such as ours present with concurrent ocular and dermatologic delusions of infestations. Ocular manifestations may be overlooked so that patients may not receive ophthalmologic assessments.11,12 Huang described a patient with delusions of ocular parasitosis whose ophthalmologic condition did not become a concern until the improvement of dermatologic DP with aripiprazole.12 Although our patient ultimately declined cataract extraction, we concur with Huang’s recommendations that comprehensive and regular ophthalmologic evaluations be conducted in a patient with combined ocular and dermatologic DP.12

Complex Visual Hallucinations

CVHs occur in the setting of a clear sensorium.21,22 Examples include people, deformed faces, inanimate objects, and animals. Further, these hallucinatory objects may interact with kinetic properties on complex scenes. They occur more commonly in poor lighting and in those with social isolation. The differential diagnosis of CVH includes Parkinson disease, delirium tremens, LBD, CBS, epilepsy, and schizophrenia.21,22 The most common causes of visual hallucinations are synucleinopathies such as Parkinson disease and LBD. In fact, the diagnosis of Parkinson disease or LBD should be questioned if complex visual hallucinations do not occur during the course of these illnesses.21-23 Core features of LBD are (1) fluctuating cognition and inattention, (2) recurrent detailed visual hallucinations, and (3) spontaneous features of parkinsonism.23 LBD is in the differential diagnosis of both delusional parasitosis and CVHs and was excluded in the diagnostic workup in our patient.

The complex physiological modulation of neurotransmitters in normal visual perception includes dopaminergic, serotoninergic, cholinergic, and GABAergic effects.21,22 Interestingly, dopamine was implicated in the pathogenesis of CVH in similarity to the pathogenesis of DP. This was supported by the efficacy of antipsychotics in the therapy of hallucinations. However, more recent studies implicated serotoninergic dysfunction in the pathogenesis of CVH. This theory was supported by the known activation of the serotonergic systems in LSD-induced hallucinations.21

Charles Bonnet Syndrome and an Association with Epilepsy

CBS is defined by the triad of complex visual hallucinations, visual impairment, and preserved cognitive function.24,25 Complex visual hallucinations in CBS is theorized as a deafferentation along the visual pathways and resultant adaptive supersensitivity in the occipital lobe. CBS can be conceptualized as visual release hallucinations, a type of psychophysical visual disturbance leading to complex visual hallucinations in the setting of partial or severe blindness.24,25 Thus, geriatricians should be cognizant that visual hallucinations may signify actual visual damage. Serotonin has been implicated as a neurotransmitter involved in the pathogenesis of CBS. Lang et al demonstrated that serotonin levels were significantly lower in sensory-deprived cortex in patients with CBS, and that selective serotonin reuptake inhibitors are an effective and well-tolerated therapy for CVH in the setting of CBS.25 He speculated that selective serotonin reuptake inhibitor treatment may change neuronal excitability in occipital regions that are responsible for visual attention and hallucinations in patients with CBS. Chen et al also reported successful resolution of CBS in a patient with right occipital infarction with serotonergic therapy.24

Our patient had an EEG performed because focal seizures can cause complex visual hallucinations, and his test was normal. We considered epilepsy because epileptic disorders have been rarely described in the medical literature in association with CBS.26,27 Ossola et al described a patient with a history of stroke who presented with worsening of existing deficits, new CVHs, and EEG revealed right-sided periodic lateralized epileptiform discharges of the plus type and focal seizure. In this very interesting case, adjustment of antiepileptic therapy led to resolution of CBS, disappearance of epileptic seizures, and restoration of prior neurological status.26 Brown-Vargas et al reported a patient who had occipital lobe epilepsy that presented as CBS. This patient developed CVHs following acute hemianopsia. EEG revealed near-continuous epileptiform discharges in the left occipital lobe.27

Concurrent Delusional Parasitosis and Complex Visual Hallucinations

To our knowledge, there are only 4 prior case reports that describe CVHs occurring in the setting of delusional parasitosis6-9 (see Table 1). Whenever visual or auditory hallucinations develop concurrently with delusions, the differential diagnosis includes psychosis such as from schizophrenia, drugs or toxins, and LBD. Based on the medical literature and our report, we believe that CBS should be added to this list. Delusions of ocular parasitosis in our patient led to vision loss from both ocular damage and voluntary eye closure. CVHs followed thereafter in this chain of events.

Table 1. Patients with concurrent delusional parasitosis and complex visual hallucinations ever reported in the medical literature

Source Sex/age Treatment Dose that achieved remission Mechanism
Rocha et al.6 F/95 Aripiprazole 15 mg Charles Bonnet
Hirakawa et al.7 F/74 Olanzapine 12.5 mg/d Micropsia
Kanazawa et al.8 F/74 No treatment Not available Senile dementia
Duarte et al.9 F/75 Aripiprazole 15 mg Charles Bonnet
Whitfield, et al. M/78 Aripiprazole 6 mg Charles Bonnet

Rocha described a 95-year-old female with severe visual impairment, who had DP of worms on her skin and body, who subsequently developed CVHs of small children on walls.6 He postulated that the CVHs were from CBS that responded successfully to aripiprazole. Hirakawa et al described a 74-year-old female with DP of insects that were crawling and burrowing on her skin and CVH of maggots, tiny horses, dogs, and cats, who was treated with olanzapine.7 He postulated that the CVH were best understood in terms of micropsia, the situation in which the vision of large animals derived from visual hallucinations were made smaller and merge into the size of objects of DP. This connection facilitated the integrity of 2 different psychopathological syndromes because the microscopia was limited to the objects of visual hallucinations and not of the real world.

Kanazawa and Hata described a 74-year-old female who described ringworms wriggling in her stomach who later developed CVHs in the form of lilliputian hallucinations, which they postulated were derived from undetected brainstem lesions and senile dementia.8 Finally, Duarte et al reported a 75-year-old female on peritoneal dialysis with DP of small living organisms on her skin who developed CVH from CBS that was treated successfully with aripiprazole.9

The average age of this cohort of 5 patients with concurrent DP and CVH was 79.2 years with an age range from 74 to 95 years. Four of the 5 patients were female. CBS was the underlying process for the CVH in 3 of the 5 cases. Full remission of the hallucinations was achieved in each of these cases with aripiprazole at a dosage of 15 mg.6,9

Therapeutic Relationship in 2 Difficult Syndromes

Delusions of parasitosis and CVHs are both associated with social stigma. Hence, it is critical that the provider establish rapport with patients and their family and friends through respectful and empathic shared decision making.28 We believe that a therapeutic relationship facilitated our patient’s acceptance of antipsychotic therapy even though he was fixated that his problem was primarily an infectious process. Direct confrontation with a patient is rarely successful because by definition delusions are fixed and nonmodifiable. We used the following best practices in shared decision making.

Patients often do not fully understand their health conditions, treatment options, and potential side effects. Patient and provider communications can be assessed through patient teach back as patients repeat information back in their own words.

Understanding patient preferences begins with asking how significant a role patients desire to be involved in their care. Doctors should not assume but rather always ask patients what are their main concerns to motivate patients to be motivated and engaged in shared decision making.

Engaging family members and caregivers is important because patients lean on their loved ones, especially in times of poor health. Doctors should provide education and support that is patient and family centered approach.28

Antipsychotic Therapy for Both Delusions of Parasitosis and Complex Visual Hallucinations

Although there are no evidence-based guidelines for the pharmacotherapy of DP or CVH, antipsychotics are considered the most favorable pharmacological intervention for controlling symptoms. The therapeutic efficacy of antipsychotics in these conditions is supported only by systematic reviews, case series, and several case reports.13 There have been no randomized controlled trials, which we believe are imperative because of the potential side effects including sudden death of antipsychotic therapy, especially in the elderly. We believe that these randomized controlled trials have not been performed because of the relative infrequency of these conditions, and especially their subgroups.

The use of pimozide as the traditional first-generation antipsychotic to treat DP significantly decreased with the advent of atypical antipsychotics. Pimozide unfortunately was associated with severe potential side effects including extrapyramidal symptoms, neuroleptic malignant syndrome, and electrocardiographic QT interval aberrations.29-31 Second-generation antipsychotics (SGA) subsequently became the drug of choice for delusional parasitosis and complex visual hallucinations. Risperidone, olanzapine, and quetiapine are the best studied of the SGA for delusional parasitosis.29,30 Similarly, the evidence for antipsychotic therapy in CVHs is very limited. The most studied of the SGA are risperidone, olanzapine, and aripiprazole.13,29,30

Aripiprazole is a new-generation antipsychotic that functions as a partial dopamine D2 agonist, partial agonist at the serotonin 5HT1a receptor, and antagonist at the 5-HT2A receptor.13-15, 29, 31 Aripiprazole appears to possess the best pharmacology of all antipsychotics with better tolerability and safety with respect to weight gain, hyperprolactinemia, sedation, extrapyramidal symptoms, and metabolic syndrome. These favorable distinctions are especially important for geriatric patients.31 Like its predecessors, aripiprazole’s therapeutic efficacy for DP and CVH is lacking in large case series and evidence-based guidelines.13,29,30,31 Because of the unfavorable metabolic changes and increased risk of death associated with antipsychotic use in the elderly, we chose aripiprazole for our patient because it has the cleanest safety profile (Table 2).

Table 2. Comparison of aripiprazole with other antipsychotics for delusions and hallucinations

Drug Mechanism Dosing Safety Tolerability
Aripiprazole Quinolinone antipsychotic with high affinity for D2, D3, 5-HT1A, and 5-HT2A receptors; moderate affinity for D4, 5-HT2C, 5-HT7, alpha1 adrenergic, and H1 receptors. It also possesses moderate affinity for the serotonin reuptake transporter; partial agonist at the D2 and 5-HT1A receptors; antagonist at the 5-HT2A receptor Starting dose 2 mg, increased by 2 mg every 2 wk; typical dose 8-12 mg/d Black box warning for increased risk of suicidal thinking in children, adolescents, and young adults Weight gain: +
HLD: −
EPS: +
Sedation: +
Anticholinergic: −
QTC prolongation: −/+
Risperidone Benzisoxazole atypical antipsychotic with high 5-HT2 and dopamine-D2 receptor antagonist activity; high affinity as an antagonist at alpha1, alpha2 adrenergic, and histaminergic receptors; low to moderate affinity for 5-HT1C, 5-HT1D, and 5-HT1A receptors; weak affinity for D1 Starting dose 0.5 mg/d (given as 1 or 2 daily doses) and increased weekly to the lowest clinically effective dose. The dose can be increased up to 8 mg/d Weight gain: +++
HLD: +
EPS: +++
Sedation: +
Anticholinergic: +
QTC prolongation: ++
Olanzapine Second-generation thienobenzodiazepine antipsychotic; potent antagonism of serotonin 5-HT2A and 5-HT2C, dopamine D1-4, histamine H1, and alpha1-adrenergic receptors; moderate antagonism of 5-HT3 and muscarinic M1-5 receptors; weak binding to GABA-A, BZD, and beta-adrenergic receptors Starting dose 2.5 mg/d; typical dose 2.5 to 7.5 mg/d Weight gain: ++++
HLD: ++++
EPS: −/+
Sedation: ++
Anticholinergic: ++
QTC prolongation: ++
Quetiapine Dibenzothiazepine atypical antipsychotic with dopamine type 2 (D2) and serotonin type 2 (5-HT2) antagonism; antagonist at serotonin 5-HT1A and 5-HT2, dopamine D1 and D2, histamine H1, and adrenergic alpha1- and alpha2-receptors Starting dose 25-50 mg; typical dose 200 mg daily Weight gain: +++
HLD: +++
EPS: −/+
Sedation: ++
Anticholinergic: ++
QTC prolong: ++

BZD - benzodiazepine

EPS - extrapyramidal symptoms

HLD - hyperlipidemia


Although data are limited, it is possible to use SGA to treat CVHs occurring concurrently with DP. Our patient presented with acquired functional blindness from his ocular DP; he subsequently developed CVHs of inanimate objects, animals, and shapes. Upon establishing therapeutic rapport, we were able to initiate antipsychotic therapy in spite of his initial severe resistance to all psychiatric evaluations. A collaborative, supportive, and empathic geriatrics approach was instrumental in gaining the trust and cooperation of the patient. This overcame the integral feature inherent in DP that is the nonmodifiable fixation that the parasites are medical and not psychiatric. The patient experienced excellent tolerability with significant symptom relief. Further trials are warranted to study the use of SGA, specifically aripiprazole in these conditions. This paper demonstrates that in patients with ocular and dermatologic DP that each condition should be investigated thoroughly and independently. In the setting of concurrent DP and CVH from CBS, LBD should be excluded in the differential diagnosis.

Disclosure Statement

The author(s) have no conflicts of interest to disclose.


There were no sources of funding for this manuscript.

Abbreviations are approved in the AMA Manual of Style for appropriate abbreviations.

Author Affiliations

Department of Internal Medicine, Camp Springs Medical Center, Kaiser Permanente, Temple Hills, MD

Corresponding Author

Hien T Nguyen, MD ()

Author Contributions

Nakiiya Whitfield, Pharm D, participated in the drafting, critical review, and submission of the final manuscript. Anne Krasniak, Pharm D, participated in the drafting, critical review, and submission of the final manuscript. Hien Nguyen, MD, participated in the drafting, critical review, and submission of the final manuscript.

How to Cite this Article

Whitfield NT, Krasniak AE, Nguyen HT. Concurrent delusions of ocular parasitosis and complex visual hallucinations from Charles Bonnet syndrome treated successfully with aripiprazole in an elderly male: A case report. Perm J 2020;25:20.132. DOI: 10.7812/TPP/20.132


1. Edlich RF, Cross CL, Wack CA, Long WB. Delusions of parasitosis. Am J Emerg Med 2009 Oct;27:997-9. DOI:

2. Laidler N. Delusions of parasitosis: a brief review of the literature and pathway for diagnosis and treatment. Dermatol Online J 2018 Jan 15;24(1):13030/qt1fh739nx. PMID: 29469757.

3. Mumcuolglu KY, Leibovici V, Reuveni I, Bonne O. Delusional Parasitosis: Diagnosis and Treatment. Isr Med Assoc J. 2018 Jul;20(7):456-60 PMID: 30109800.

4. Reich A, Kwiatkowska D, Pacan P. Delusions of parasitosis: An update. Dermatol Ther (Heidelb) 2019 Dec;13:631-8. DOI:

5. Thibierge G. Les acarophobes. Rev Gen Clin Ther 1894;32:373–6.

6. Rocha FL, Caramelli P, Oliveira LC. Complex visual hallucinations and delusional infestation comorbidity. Arq Neuropsiquiatr 2012 Jul;70:553–4. DOI:

7. Hirakawa H, Terao T, Kanehisa M. Coexistence of delusional parasitosis and complex visual hallucinations with micropsia. J Neuropsychiatry Clin Neurosci. 2016 Jan;28:e10-2. DOI:

8. Kanazawa A, Hata T. Coexistence of the Ekbom syndrome and lilliputian hallucination. Psychopathology 1992 Feb;25:209–11. DOI:

9. Duarte C, Choi KM, Li CL. [Delusional parasitosis associated with dialysis treated with aripiprazole]. Acta Med Port 2011 May-Jun;24(3):457-62. Portuguese. Epub 2011 Aug 12. PMID: 22015035.

10. Thakkar A, Ooi KG, Assad N, Coroneo M. Delusional infestation: Are you being bugged? Clinical Opthalmology 2015 Jun;9:967-70. DOI:

11. Meraj A, Din AU, Larsen L, Liskow BI. Self inflicted corneal abrasions due to delusional parasitosis. BMJ Case Rep 2011 Jul;2011. DOI:

12. Huang W, Li-RenC. Aripirazole in the treatment of delusional parasitosis with ocular and dermatologic presentations. J Clin Psychopharmacol 2013 Apr;33:272-3. DOI:

13. Campbell EH, Elston DM, Hawthorne JD, Beckert BR. Diagnosis and management of delusional parasitosis. J Am Acad Dermatol 2019 May;80:1428-38. DOI:

14. Lyell A. Delusions of parasitosis. Br J Dermatol 1983 Apr;108:485-99. DOI:

15. McKeith IG, Boeve BF, Dickson DW, et al. Diagnosis and management of dementia with Lewy bodies: Fourth consensus report of the DLB Consortium. Neurology 2017 Jul;89:88-100. DOI:

16. Barsky AJ, Borus JF. Functional somatic syndromes. Ann Intern Med 1999 Jun;130:910-21. DOI:

17. Foster AA, Hylwa SA, Bury JE, Davis MDP, Pittelkow MR, Bostwick JM. Delusional infestation: Clinical presentation in 147 patients seen at Mayo Clinic. J Am Acad Derm 2012 Oct;67:e1-10. DOI:

18. Lynch PJ. Delusions of parasitosis. Semin Dermatol 1993 Mar;12(1):39-45. PMID: 8476732.

19. Haas NL, Nicholson A, Haas MRC. Delusional parasitosis as a presenting symptom of occipital lobe cerebrovascular accident. Am J Emerg Med 2019 Oct;37:e3-5. DOI:

20. Sherman MD, Holland GN, Holsclaw DS, Weisz JM, Omar OH, Sherman RA. Delusions of ocular parasitosis. Am J Ophthalmol 1998 Jun;125:852-6. DOI:

21. Russo M, Carraini C, Dono F, et al. The pharmacology of visual hallucinations in synucleinopathies. Front Pharmacol 2019 Dec;10:1-16. DOI:

22. Cho SS, Strafella AP, Duff-Canning S, et al. The relationship between serotonin-2A receptor and cognitive functions in nondemented Parkinsons’s disease patients with visual hallucinations. Mov Disord Clin Pract 2017 Jan;4:698-709. DOI:

23. Ochiai S, Sugarwara H, Kajio Y, et al. Delusional parasitosis in dementia with Lewy bodies: A case report. Ann Gen Psychiatr 2019 Dec;18:29-31. DOI:

24. Chen C-C, Liu HC. Low-dose aripiprazole resolved complex hallucinations in the left visual field after right occipital infarction (Charles Bonnet syndrome). Psychogeriatrics 2011 Jun;11(2):116-8. DOI:

25. Lang U, Stogowski D, Schulze, et al. Charles Bonnet syndrome: Successful treatment of visual hallucinations due to vision loss with selective serotonin reuptake inhibitors. Psychopharmacology 2007 Jul 21:53-5. DOI:

26. Ossola M, Romani A, Tavazzi E, Pichiecchio A, Galimberti CA. Epileptic mechanisms in Charles Bonnet syndrome. Epilepsy Behav 2010 May;1:119-22. DOI:

27. Brown-Vargas D, Cienki J. Occipital lobe epilepsy presenting as Charles Bonnet syndrome. Am J Emerg Med 2012 Nov;30:2102.e.5-6. DOI:

28. Raue P, Schulberg H, Bruce M, et al. Effectiveness of shared decision-making for elderly depressed minority primary care patients. Am J Geriatr Psychiatr 2019 Aug;27:883-93. DOI:

29. Feudenmann RW, Lepping P. Second-generation antipsychotics in primary and secondary delusional parasitosis: Outcome and efficacy. J Clin Psychopharmacol 2008 Oct;28:500-8. DOI:

30. Gareri P, Serugra-Garcia C, Graziella V, et al. Use of atypical antipsychotics in the elderly: A clinical review. Clin Interv Aging 2014 Aug;9:1363-73. DOI:

31. Bennassar A, Guilabert A, Alsina M, Pintor L, Mascaró JM Jr., Treatment of delusional parasitosis with aripiprazole. Arch Dermatol 2009 Apr;145:500-1. DOI:

Keywords: aripiprazole, Charles Bonnet syndrome, complex visual hallucinations, delusional parasitosis, elderly


Click here to join the eTOC list or text ETOC to 22828. You will receive an email notice with the Table of Contents of The Permanente Journal.


2 million page views of TPJ articles in PubMed from a broad international readership.


Indexed in MEDLINE, PubMed Central, EMBASE, EBSCO Academic Search Complete, CrossRef, and SciVerse/Scopus.




ISSN 1552-5775 Copyright © 2020

All Rights Reserved