Treatment of delusional parasitosis
- Kathryn N Suh, MD, FRCPC
Kathryn N Suh, MD, FRCPC
- Associate Professor of Medicine
- University of Ottawa, Canada
- Jay S Keystone, MD, MSc (CTM), FRCPC
Jay S Keystone, MD, MSc (CTM), FRCPC
- Professor of Medicine
- University of Toronto, Canada
Delusional parasitosis is a rare disorder in which affected individuals have the fixed, false belief (delusion) that they are infected by "bugs": parasites, worms, bacteria, mites, or other living organisms. As with all delusions, this belief cannot be corrected by reasoning, persuasion, or logical argument. Many affected individuals are quite functional; for the minority, delusions of parasitic infection may interfere with usual activities .
Delusional parasitosis is a delusional disorder of the somatic type , a subgroup of delusional disorders in which nonexistent disease or alteration of the body forms the basis of the disorder. Delusions of parasitosis are the most common form of monosymptomatic hypochondriacal psychosis; others include delusions of dysmorphism and delusions of body odor or halitosis.
This topic addresses the treatment of delusional parasitosis. The epidemiology, clinical presentation, and diagnosis of delusional parasitosis are discussed separately. Other psychotic disorders are discussed separately. First and second-generation antipsychotic drugs are discussed separately. (See "Delusional parasitosis: Epidemiology, clinical presentation, assessment and diagnosis" and "Postpartum psychosis: Epidemiology, clinical manifestations, assessment, and diagnosis" and "First-generation antipsychotic medications: Pharmacology, administration, and comparative side effects" and "Second-generation antipsychotic medications: Pharmacology, administration, and side effects" and "Pharmacotherapy for schizophrenia: Acute and maintenance phase treatment" and "Pharmacotherapy for schizophrenia: Side effect management".)
Two forms of delusional parasitosis are widely recognized [3,4]:
Primary delusional parasitosis — Primary delusional parasitosis is a psychiatric disorder with the delusion of parasitic infection as its only manifestation.
- Lynch PJ. Delusions of parasitosis. Semin Dermatol 1993; 12:39.
- American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5), American Psychiatric Association, Arlington, VA 2013.
- Musalek M, Bach M, Passweg V, Jaeger S. The position of delusional parasitosis in psychiatric nosology and classification. Psychopathology 1990; 23:115.
- Freinhar JP. Delusions of parasitosis. Psychosomatics 1984; 25:47.
- Gould WM, Gragg TM. Delusions of parasitosis. An approach to the problem. Arch Dermatol 1976; 112:1745.
- Wykoff RF. Delusions of parasitosis: a review. Rev Infect Dis 1987; 9:433.
- Aw DC, Thong JY, Chan HL. Delusional parasitosis: case series of 8 patients and review of the literature. Ann Acad Med Singapore 2004; 33:89.
- Winsten M. Delusional parasitosis: a practical guide for the family practitioner in evaluation and treatment strategies. J Am Osteopath Assoc 1997; 97:95.
- Lyell A. The Michelson Lecture. Delusions of parasitosis. Br J Dermatol 1983; 108:485.
- Zanol K, Slaughter J, Hall R. An approach to the treatment of psychogenic parasitosis. Int J Dermatol 1998; 37:56.
- Lepping P, Russell I, Freudenmann RW. Antipsychotic treatment of primary delusional parasitosis: systematic review. Br J Psychiatry 2007; 191:198.
- Manschreck TC, Khan NL. Recent advances in the treatment of delusional disorder. Can J Psychiatry 2006; 51:114.
- Trabert W. 100 years of delusional parasitosis. Meta-analysis of 1,223 case reports. Psychopathology 1995; 28:238.
- Bhatia MS, Jagawat T, Choudhary S. Delusional parasitosis: a clinical profile. Int J Psychiatry Med 2000; 30:83.
- Reilly TM, Batchelor DH. The presentation and treatment of delusional parasitosis: a dermatological perspective. Int Clin Psychopharmacol 1986; 1:340.
- 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; 138:1030.
- Ungvári G, Vladár K. Pimozide treatment for delusion of infestation. Act Nerv Super (Praha) 1986; 28:103.
- Hamann K, Avnstorp C. Delusions of infestation treated by pimozide: a double-blind crossover clinical study. Acta Derm Venereol 1982; 62:55.
- Flockhart DA, Drici MD, Kerbusch T, et al. Studies on the mechanism of a fatal clarithromycin-pimozide interaction in a patient with Tourette syndrome. J Clin Psychopharmacol 2000; 20:317.
- Mackin P. Cardiac side effects of psychiatric drugs. Hum Psychopharmacol 2008; 23 Suppl 1:3.
- May WW, Terpenning MS. Delusional parasitosis in geriatric patients. Psychosomatics 1991; 32:88.
- Srinivasan TN, Suresh TR, Jayaram V, Fernandez MP. Nature and treatment of delusional parasitosis: a different experience in India. Int J Dermatol 1994; 33:851.
- Freyne A, Wrigley M. Delusional infestation in an elderly population. Ir Med J 1994; 87:86.
- De León OA, Furmaga KM, Canterbury AL, Bailey LG. Risperidone in the treatment of delusions of infestation. Int J Psychiatry Med 1997; 27:403.
- Safer DL, Wenegrat B, Roth WT. Risperidone in the treatment of delusional parasitosis: a case report. J Clin Psychopharmacol 1997; 17:131.
- Gallucci G, Beard G. Risperidone and the treatment of delusions of parasitosis in an elderly patient. Psychosomatics 1995; 36:578.
- Wenning MT, Davy LE, Catalano G, Catalano MC. Atypical antipsychotics in the treatment of delusional parasitosis. Ann Clin Psychiatry 2003; 15:233.
- Nakaya M. Olanzapine treatment of monosymptomatic hypochondriacal psychosis. Gen Hosp Psychiatry 2004; 26:166.
- Freudenmann RW. [A case of delusional parasitosis in severe heart failure. Olanzapine within the framework of a multimodal therapy]. Nervenarzt 2003; 74:591.
- Meehan WJ, Badreshia S, Mackley CL. Successful treatment of delusions of parasitosis with olanzapine. Arch Dermatol 2006; 142:352.
- Freudenmann RW, Schönfeldt-Lecuona C, Lepping P. Primary delusional parasitosis treated with olanzapine. Int Psychogeriatr 2007; 19:1161.
- Freudenmann RW, Kühnlein P, Lepping P, Schönfeldt-Lecuona C. Secondary delusional parasitosis treated with paliperidone. Clin Exp Dermatol 2009; 34:375.
- Koo J, Gambla C. Delusions of parasitosis and other forms of monosymptomatic hypochondriacal psychosis. General discussion and case illustrations. Dermatol Clin 1996; 14:429.
- Rocha FL, Hara C. Aripiprazole in delusional parasitosis: Case report. Prog Neuropsychopharmacol Biol Psychiatry 2007; 31:784.
- Driscoll MS, Rothe MJ, Grant-Kels JM, Hale MS. Delusional parasitosis: a dermatologic, psychiatric, and pharmacologic approach. J Am Acad Dermatol 1993; 29:1023.