A Case of Delusional Parasitosis in a 58-year-old Woman

Taral R. Sharma, MD, MBA
Clinical Instructor, University of South Carolina School of Medicine, Greenville, SC; Staff Psychiatrist, South Carolina Department of Mental Health, Anderson, SC

Michal C. Cieraszynski, DO
Staff Psychiatrist, Department of Veteran’s Affairs, Salem, Va.

First published in Primary Psychiatry | October 30, 2013.

Case description

“Ms. A” is a 58 year-old white, divorced, unemployed female, with past psychiatric history of major depressive disorder and anxiety disorder NOS, who presented to emergency department (ED) with complaints of "lice and bugs" crawling from her skin and rectum for several weeks. Upon presentation to ED, she stated that she had visited an ED 3 weeks earlier for the same symptoms, where she was diagnosed with scabies and was prescribed permethrin cream. She reported using several tubes of permethrin cream over the previous 2 weeks with no relief of her symptoms. Initially she had only been itching, with a feeling of crawling under her skin, but upon presentation to ED she reported that bugs were crawling “all over” her. She also reported some of them as “brown and gray” and beetle-like, burrowing from under her shin and left arm. At one point during the interview she reported larvae coming from her anus, and she feared that they might try to attack other parts of her body, including her genital region. She had decided to use duct-tape to try to keep the bugs in. She also stated that she was afraid of infecting other parts of her house, as well as people around her. She had fumigated much of her house with bug spray. She had considered using grapefruit seed extract, and reported taking a bath in kerosene to remove the bugs. Later, she admitted to using a tampon dipped in bug spray in an attempt to keep the larvae from exiting her anus.

Ms. A denied any history of psychiatric hospitalization or suicide attempts. Past medical history was significant for cervical radiculopathy, vitreous degeneration, menopause, and hypothyroidism. Family history was significant for mother with depression and father with anger problems. Review of systems was significant for rash, skin lesions, itching and bugs on skin, as well as larvae in the rectum. Physical examination showed multiple papular-like lesions, some with scabs on chest, arms, and legs, bilaterally. There were no signs of acute infection, oozing, or larvae. No erythematous skin rashes, evidence of scabies, genital parasitic infection, or rashes were noted. Significant labs included hemoglobin of 11.8 gm/dL. Urine drug screen was negative for cannabis, cocaine, opiates, benzodiazepines, amphetamines, barbiturates, or PCP. Computerized tomography scan without contrast showed normal unenhanced brain.

Mental status examination showed a middle aged white female, dressed in appropriate clothes, but disheveled, with unkempt hair and multiple skin lesions. Her manner was cooperative and pleasant but with mild psychomotor agitation noted. Speech was mildly increased in rate and normal rhythm. Her mood was described as “sad,” affect was labile (tearful with occasional laughing). Thought process was circumstantial and illogical, and was positive for evidence of delusions and paranoia. She reported seeing “gray bugs” under her left arm, “brown bugs” in her chin, as well as “white larvae and scabies” coming from her anal region. Her cognition was intact with well-oriented adult woman who is able to attend and concentrate to basic screening questions. Her short term and long term memory was intact with 3/3 registration and recall, and she was able to spell WORLD backwards.

She was diagnosed with delusional disorder, somatic type (formerly known as “delusional parasitosis”) and was hospitalized in inpatient psychiatric unit on a voluntary basis. She was started on risperidone 1 mg at bedtime for delusions of somatic type, which was up titrated to 3 mg at bedtime to optimally control her delusions. She also complained of depression, which was treated with paroxetine at first, but, after she reported having headaches, was changed to venlafaxine extended release 37.5 mg/day, which was increased to 75 mg/day to optimally control her depressive symptoms. Complications included prolonged hospitalizations due to her fixed delusions and treatment of depression.


Ekbom syndrome, or delusional parasitosis, is described mainly in presenile women who are unmarried or living alone.1 The presenting dermatological symptom is persistent pruritus, and the patients often take medical advice from several practitioners one after another.1 Delusional parasitosis is a somatic type delusional disorder in which sufferers maintain a fixed false belief that they are infested with parasites. It is usually diagnosed as delusions of somatic type, a subtype of delusional disorder. The mean age of onset is 56.9 years, and the male-to-female ratio is 1:1.5.2 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.3 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.2,3 Management initially involves ruling out a general medical condition and excluding the use of drugs, illicit or prescribed. Pimozide, a dopamine antagonist, is the traditional treatment, 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.2,4,5 Careful strategy is required to convince patients with delusional parasitosis of the importance of a psychiatric referral.


Disclosure: Drs. Sharma and Cieraszynski report no affiliations with, or financial interests in, any organization that may pose a conflict of interest.


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2. Zomer SF, De Wit RF, Van Bronswijk JE, Nabarro G, Van Vloten WA. Delusions of parasitosis: a psychiatric disorder to be treated by dermatologists? An analysis of 33 patients. Br J Dermatol. 1998;138:1030-1032.

3. Le L, Gonski PN. Delusional parasitosis mimicking cutaneous infestation in elderly patients. Med J Aust. 2003;179:209-210.

4. Gowda BS, Heebbar S, Sathyanarayana MT. Delusional parasitosis responding to risperidone. Indian J Psychiatry. 2002;44:382-383.

5. Hanumantha K, Pradhan PV, Suvarna B. Delusional parasitosis–study of cases. J Postgrad Med. 1994;40:222-224.