“Holes in My Head”: A Case of Primary Delusional Parasitosis in a Patient With End-Stage Renal Disease

To the Editor: Delusional parasitosis is a somatic type delusional disorder in which sufferers maintain a fixed false belief that they are infested with parasites. Secondary forms of delusional parasitosis are addressed by treating the primary associated psychological or physical condition. We present a case of primary delusional parasitosis in a patient with end-stage renal disease.

 

Case report. Mr A, a 63-year-old African American man, was admitted in 2010 to the medical floor from the dialysis unit after making some bizarre statements during a dialysis session. Psychiatry consult was requested by the medical team after the patient continued to endorse a fixed delusion that he had had 2 holes in his forehead for 2 months, which appeared intermittently and were reported by the patient to have closed before he was interviewed by the psychiatric consult team. Mr A also stated that he was not sure if any worms were crawling around in his head (pointing to his head) and was in the hospital to get the condition investigated. Upon further interview, the patient reported feeling that bugs were crawling on his skin, and he explained that insects were the reason for his severe pruritus and chronic skin condition. The patient also had a past history of increased confusion and making bizarre statements during dialysis sessions. His medical history was significant for diabetes mellitus with retinopathy, end-stage renal disease, anemia, glaucoma with partial blindness, and cutaneous lymphocytosis as well as chronic pruritus treated by glucocorticoid.

Findings of head computed tomography without contrast were within normal limits, except for mild age-related generalized atrophy. Significant laboratory values included serum PO4 level of 6.2 mg/dL, serum magnesium level of 1.6 mg/dL, serum chloride level of 95 mg/dL, random blood glucose level of 375 mg/dL, blood urea nitrate level of 32 mg/dL, serum creatinine level of 5.5 mg/dL, and estimated glomerular filtration rate 13 mL/h. Differential diagnosis included chronic delirium due to dialysis and polypharmacy, delusional parasitosis, and cognitive disorder not other specified.

Psychiatric consultants recommended optimization of medications and reduction of polypharmacy: Mr A was using clobetasol topical cream twice a day, fluocinonide topical twice a day, and terbinafine topical cream twice a day and taking triamcinolone 80 mg 4 times a day, finasteride 5 mg at night, clonidine 0.3 mg 3 times a day, furosemide 80 mg twice a day, hydralazine 20 mg 4 times a day, heparin 5,000 mg subcutaneously 3 times a day, labetalol 400 mg 3 times a day, isosorbide mononitrate 60 mg daily, ropinirole 1 mg at night, sliding scale insulin, pravastatin 20 mg at night, sodium bicarbonate 650 mg 3 times a day, diazepam 5 mg every 8 hours as needed, and zolpidem 12.5 mg at night. The patient was prescribed a number of sedating medications, including diazepam, zolpidem, clonidine, and hydroxyzine. Both ropinirole and hydralazine have been shown to cause psychotic symptoms.1,2 The patient’s diazepam was discontinued. His medical team was also advised to start a low dose of haloperidol, 1 mg twice a day, for delusions. The medical team was advised to premedicate with an antipsychotic, adjust the patient’s dialysis schedule, and consider changing dialysate to help reduce delirium; although dialysate was not changed, the other 2 changes were implemented as recommended. Confusion and delusions subsided after 4 days, at which time he was discharged from the hospital.

 

Delusional parasitosis is usually diagnosed as a subtype of delusional disorder. The mean age at onset is 56.9 years, and the male-to-female ratio is 1:1.5.1 Patients describe a parasitic invasion on or inside the skin; they may bring in objects such as hair, lint, or skin—the “matchbox sign”—as proof of the infestation despite normal findings on examination.2 Patients rarely seek the help of a psychiatrist; rather, because of their belief in a somatic complaint, patients often see primary care physicians or dermatologists for treatment.1,2 Management initially involves ruling out a general medical condition and excluding the use of drugs, illicit or prescribed. Traditionally, treatment is pimozide, a dopamine antagonist, although some patients may respond to neuroleptics such as haloperidol or risperidone. Duration of treatment varies from 2 weeks to 3 months before use is tapered, but compliance can be challenging.1,3,4 Careful strategy is required to convince patients with delusional parasitosis of the importance of a psychiatric referral.

References

1. Perea E, Robbins BV, Hutto B. Psychosis related to ropinirole. Am J Psychiatry. 2006;163(3):547–548. PubMed doi:10.1176/appi.ajp.163.3.547

2. Moser M, Syner J, Malitz S, et al. Acute psychosis as a complication of hydralazine therapy in essential hypertension. J Am Med Assoc. 1953;152(14):1329–1331. PubMed doi:10.1001/jama.1953.63690140001008

3. Zomer SF, De Wit RF, Van Bronswijk JE, et al. Delusions of parasitosis: a psychiatric disorder to be treated by dermatologists? an analysis of 33 patients. Br J Dermatol. 1998;138(6):1030–1032. PubMed doi:10.1046/j.1365-2133.1998.02272.x

4. Le L, Gonski PN. Delusional parasitosis mimicking cutaneous infestation in elderly patients. Med J Aust. 2003;179(4):209–210. PubMed

5. Safer DL, Wenegrat B, Roth WT. Risperidone in the treatment of delusional parasitosis: a case report (letter). J Clin Psychopharmacol. 1997;17(2):131–132. PubMed doi:10.1097/00004714-199704000-00020

6. Hanumantha K, Pradhan PV, Suvarna B. Delusional parasitosis—study of 3 cases. J Postgrad Med. 1994;40(4):222–224. PubMed

Taral R. Sharma, MD, MBA

trsharma1@carilionclinic.org

Geoffrey M. Bader, MD

Daniel B. Kline, MD

Author affiliations: Department of Psychiatry, Psychiatry Residency Program, Carilion Clinic Virginia Tech-Carilion School of Medicine, Roanoke (Drs Sharma and Kline); and Department of Consult-Liaison Psychiatry, Veterans Affairs Medical Center, Salem (Dr Bader), Virginia.

Potential conflicts of interest: None reported.

Funding/support: None reported.

Previous presentation: Presented at Psychiatry Grand Rounds, Veterans Affairs Medical Center Salem, Virginia.

Published online: May 3, 2012.