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Delusional disorders in dermatology: A brief review

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Delusional disorders in dermatology: a brief review
David T Robles MD PhD1, Sharon Romm MD2, Heidi Combs MD2, Jonathan Olson BS1, Phil Kirby MD1
Dermatology Online Journal 14 (6): 2

1. Department of Medicine, Division of Dermatology, University of Washington Medical Center, Seattle, WA.
2. Department of Psychiatry, University of Washington Medical Center, Seattle, WA


There are several unique psychiatric disorders that are likely to present to a dermatologist because of their accompanying skin complaints. Delusions of parasitosis (DP) is a fixed, false belief of parasitic infestation that may lead patients to compulsively self-mutilate while attempting to remove the non-existant parasites. Morgellons disease is a controversial condition characterized by a fixed belief that fibers that are imbedded or extruding from the skin; this condition is likely in the spectrum of DP. Body dysmorphic disorder (BDD) is a preoccupation with an imagined defect in appearance that causes significant distress and is associated with time comsuming rituals, isolation, depression, and increased risk of suicide. Olfactory reference syndrome (ORS) is a preoccupation with body odor leading to the stigmata of shame, embarrassment, and social isolation. This brief review examines each of these conditions and their management because any one of them may present to a dermatologist.


Dermatologists may be the first provider or even the provider of choice to care for patients with skin complaints accompanied by psychiatric disorders. Patients can present to the dermatologist rather than to a psychiatrist because they are convinced they have a problem confined to their skin rather than their psyche [1]. Because of the stigma attached to psychiatric referral, the dermatologist may be called upon to diagnose and treat complex and often unremitting psychiatric conditions.

Patients can present with delusions related to the skin. Such disorders are characterized by a fixed, false belief that is unshakeable despite evidence to the contrary. In this review, we describe delusions of parasitosis, body dysmorphic disorder, Morgellons disease and olfactory reference syndrome and offer criteria for diagnosis and options for management.

Delusions of parasitosis

Delusions of parasitosis (DP) was formally diagnosed as a delusional disorder, somatic type, according to the Diagnostic and Statistical Manual of Mental Disorders (DSM) IV [2]. It was previously called "monosymptomatic hypochondriasis," a term indicating a delusion of infestation by parasitic organisms. Patients with DP describe sensations of crawling, burrowing and even biting from parasites. They may offer elaborate, detailed descriptions of their parasites and may perform ritualistic purifications to rid themselves of the offending organism. These obsessive behaviors include picking and the application of disenfectants and pesticides. Skin is often damaged as result of this self-mutilation (Figs. 1 and 2). Patients may apply topical anti-scabetic agents such as permethrin cream in an attempt to rid themselves of parasites. Patients classically present their collection of lint, dried blood, hairs and other skin fragments (spuriously believed to be parasites) in a small box or container, the so-called "matchbox sign" [3]. Patients exhibit excoriations, prurigo nodules, or ulcerations from their manipulative efforts [4]. The delusion of infestation may be shared by a family member or significant other, a phenomenon called "folie à deux". Explaining the diagnosis of delusions of parasitosis to patients or their families is difficult especially because they are convinced of having a genuine dermatologic condition. This has led some authors to propose the term "pseudoparasitic dysaesthesia" [5].

Delusions of parasitosis is distinct from formication, in which patients experience crawling, biting or stinging sensations but are not convinced that the cause is parasites. Illicit drugs such as amphetamines can cause formication and can result in a delusional state indistinguishable from delusions of parasitosis. Cocaine abuse can be associated with visual hallucinations and the feeling of bugs crawling beneath their skin, a phenomenon referred to as "cocaine bugs" [6]. Drug history should be obtained in the initial evaluation. A thorough psychiatric history should also be obtained with careful consideration to ensure that the delusion is not part of a more global psychotic disorder, such as schizophrenia or bipolar disorder.

Patients who exhibit their symptomatology in a unilateral or dermatomal distribution must be investigated for underlying neuropathy (Fig. 2). Trigeminal neuralgia and post-herpetic neuropathy are 2 conditions that can produce severe localized neuropathic pain along with other forms of dysaesthesia. The severe discomfort may lead patients to manipulate the skin causing erosions and ulcerations. After long periods without relief these patients may come to believe that an infestation must be the source of their problem. Similar erosions and ulcerations occur in some patients who carry the diagnosis of trigeminal trophic syndrome and are initiated by nerve damage. In this condition, the dysaesthesia, erosions, and ulcerations most often occur paranasally, but one of the most common mechanisms of lesion production is through self-manipulation precipitated by the discomfort and pain [7, 8]. In some patients whose pathology is likely induced by neuropathy, gabapentin has been found to be beneficial [9].


The prevalence of delusions of parasitosis is unknown but is thought to be relatively rare. The female to male ratio is estimated at 1.4:1 for patients less than age 50 and 2.5:1 for those greater than 50 [10]. Delusions of parasitosis appears in people of diverse backgrounds but tends to be more prevalent in patients with less formal education and who have a lower socioeconomic status [11]. In a survey of over one hundred dermatologists, 85 percent had at least one patient with DP in their practice [12].


Patients characteristically lack insight into their disease and often reject psychiatric evaluation and treatment [13]. Because of this, a dermatologist may be the only provider from whom the patient will accept medication. Unfortunately, although most dermatologists have at least one patient with DP in their practice, only a fraction (15%) prescribe antipsychotics [12]. Pimozide is the antipsychotic medication that has long been considered the treatment of choice for delusions of parasitosis (Table 1) [4, 6]. This medication is a diphenylbutylpiperidine derivative anti-psychotic that is a selective blocker of dopamine D2 receptors. Pimozide is unique in its ability to antagonize the central opiate receptor system, a process that has beneficial effects on complaints of pruritus and formication [14]. As with other anti-psychotic drugs, pimozide may lead to prolongation of the QT interval. The most common adverse effect of pimozide remains extrapyramidal symptoms like stiffness and akathisia, which may occur in 10-15 percent of patients. Although tardive dyskinesia is also a concern with pimozide, the dose typically used for DP is much lower than treatment for schizophrenia, in which most cases of tardive dyskinesia have been reported [5]. Although rare and typically only associated with high doses, significant side effects such as hypotension, ventricular arrhythmias and sudden cardiac death have been reported with its use [12]. For this reason, authorities recommend a pre- and post-treatment EKG [4]. The starting dose of pimozide is 1-2 mg daily with gradual increases titrated according to clinical response. Pimozide is generally effective in doses ranging from 1 to 10 mg/day [4].

Because of the potentially serious side effects of pimozide some experts recommend the use of newer atypical antipsychotics [16]. These medications carry their own risks including hyperlipidemia, diabetes mellitus, QT interval prolongation and weight gain [17]. Atypical antipsychotics such as olanzapine and risperdone have successfully addressed delusions of parasitosis. Olanzapine has been used successfully at a dose of 5-10 mg/day and risperidone in doses of 2-4 mg/day produced favorable results [4, 14, 16, 18, 19, 20]. Mercan reports benefit from intramuscular risperidone at 37.5 mg given every two weeks [17]. Given the lack of insight patients demonstrate, noncompliance with medication presents a significant obstacle to treatment.

Figure 1Figure 2
Figure 1. Multiple linear excoriations in a patient with delusions of parasitosis
Figure 2. Patient with delusions of parasitosis holding skin and hair fragments (Courtesy of University of Washington Collection)

Morgellons disease

In the seventeenth century Sir Thomas Browne used the term Morgellons disease to describe an unusual symptom complex resembling those seen in patients today [21]. Patients with this condition maintain the unshakeable belief that fibers or some other material is imbedded or emerging from their skin. They pick and dig at their skin to extract the offending "material." They may reject the notion that they have parasites but may still exhibit the "matchbox" sign, bringing in fragments of clothing fibers, lint, hair fibers and dried skin fragments for examination.

We consider Morgellons to be within the spectrum of delusions of parasitosis, except that the patients are focused not on parasites but on "unusual material" that they believe is in their skin. We have seen a number of such patients in our clinic and all manipulate their lesions enough to self-induce irregular ulcerations. They frequently dig at their lesions with their own nails as well as house-hold items such as nail clippers or tweezers, the so-called "tweezer sign" (Robles, in press). It is important to ask patients if they use instruments in addition to fingernails because in our experience, the use of mechanical devices portends a more malignant psychological profile.

Morgellons disease has received recent attention, primarily through the internet and through the website of Morgellons Research Foundation ( The Morgellons Research Foundation claims that this condition is an emerging infectious disease [21], however, no available evidence exists to confirm this hypothesis. Some authors affiliated with the Morgellons Research Foundation claim that Lyme Borreliosis [22] has an association but this has not been substantiated.


There are no data available describing the prevalence of this syndrome. It may be seen in association with a number of psychiatric conditions including unipolar and bipolar depression, schizophrenia and abuse of drugs [21].


There are no randomized control studies to establish the recommended treatment of this disorder. Some experts discuss the importance of establishing patient rapport by referring to the delusions as Morgellons disease [23]. After ruling out an organic cause, emphasis should be placed on how disconcerting the symptoms must be for the patient.

Medication trials have been intermittently effective. Pimozide has been used in doses of 0.5-2.0 mg daily. Koblenzer believes that Pimozide, with the added anti-pruritic effect, is a preferred treatment [24]. The use of atypical antipsychotics such as risperdal, olanzapine and aripiprazole may also be of benefit [21, 23]. In our experience, the use of extra-thin hydrocolloid dressings over the ulcerations is generally very effective because it provides a mechanical barrier to manipulation and facilitates wound healing. The wounds frequently become secondarily infected, making the use of topical or systemic antibiotics an important adjunctive measure.

Body dysmorphic disorder

Body dysmorphic disorder (BDD) is a psychiatric condition revolving around preoccupation with an imagined defect in one's appearance. This condition is not classified as a psychotic but as a somatoform disorder. These are disorders characterized by physical complaints that appear to be medical in origin but that cannot be explained in terms of a physical disease, the results of substance abuse, or by another mental disorder. According to the DSM IV, diagnostic criteria are met if symptoms result in significant distress or impairment in social or occupational settings [2]. Yet, the beliefs held by patients with this condition are so unyielding that they can resemble delusions. Common complaints involve features of the head, face and body hair. Patients may also refer to unattractive thighs, stomach, breasts, buttocks, and genitals [25]. Preoccupation is associated with time consuming rituals including mirror gazing and comparison to others. Quality of life is poor with social isolation, depression and a high risk of suicide [25].

Patients with BDD may present to dermatologists and cosmetic surgeons for appearance improvement procedures [27]. They often have needless dermatological treatments and cosmetic surgeries. Patients may have a minor or non-discernable defect but believe they are deformed owing to their disturbed perception of their body image. They may worry about perceived appearance flaws for a reported average of 3-8 hours a day [28]. Patients with BDD may be aware that their preoccupations with their appearance are excessive, but they still find themselves at the mercy of their concerns [29]. Patients are convinced that the severity of their defects is great and cannot be convinced otherwise [30, 31].


The prevalence of BDD is 0.7-2 percent of the general population [26]. Most surveys find a 1:1 ratio of males to females [32]. In the patients seeking the service of a dermatologist the prevalence of BDD is much higher. Several studies have found 5-15 percent in dematologic and cosmetic surgery patients [33]. A report by Bowe suggests that the prevalence of BDD in patients presenting to a dermatologist for acne treatment was between 14 and 20 percent [24].


Patients often try multiple self-treatments. For example, they may use tanning in an attempt to conceal or improve the appearance of their perceived physical defect [34]. However, patient satisfaction is rarely achieved. For patients with BDD who seek treatment, more than half find no improvement and some patients report worsening of their initial complaint [35]. Of note, patients with body dysmorphic disorder are more likely to threaten or execute lawsuits against their treating providers [30, 33].

Although often trivialized and stigmatized, it is nonetheless important to address the negative impact on quality of life and associated depression and suicide risk. Patients with BDD have higher scores on the Yale-Brown obsessive-compulsive scale modified for BDD and show increased anxiety and depression on the Hospital and Anxiety Depression Scales [29]. There is evidence for modest benefit of SSRI antidepressants in 2 randomized controlled trials [36, 37]. The maximum tolerable dose must be taken for at least 12-16 weeks for an adequate trial [37]. There is no evidence that antipsychotics alone are beneficial. Another treatment option for BDD is Cognitive Behavioral Therapy (CBT). A recent review by Sumathipala found four randomized control trials where CBT was effective as a treatment of BDD [38]. Group therapy was also demonstrated useful. Effects were moderate to large in magnitude and the authors recommend CBT as the first line of treatment [38].

Olfactory reference syndrome (delusions of bromhidrosis)

Bromhidrosis is a chronic condition in which excessive body odor, usually an unpleasant one, emanates from the skin. This condition is determined largely by apocrine gland secretion and can substantially impair a person's quality of life. A small subset of patients may exhibit a delusion that a very unpleasant odor is emanating from their skin, a condition termed, olfactory reference syndrome (ORS). Olfactory reference syndrome is characterized by persistent preoccupation about body, oral or vaginal odor accompanied by shame, embarrassment, significant distress, avoidant behavior and social isolation. The primary feature of ORS is an olfactory delusion, and patients with ORS are diagnosed as having delusional disorder (somatic type) in DSM IV [2]. However, ORS does not have a specific DSM IV classification [2]. These patients may wash excessively, change clothes with more than usual frequency, and restrict social and domestic activities [39]. There is disagreement whether this condition fits within the spectrum of obsessive-compulsive disorder or whether it belongs in the spectrum of social anxiety disorders that includes body dysmorphic disorder [39, 40]. Devinsky et al. described a patient with right temporal lobe epilepsy who developed the chronic delusion that his body emitted a foul odor, speculating an association of right hemisphere lesions and this disorder [41].


There is very little data available that identifies the prevalence of ORS. One study by Pryse-Phillips studied 36 patients with ORS and found average age of onset was 25.4 years and 78 percent were male [42].


Given the poor understanding and lack of definitive diagnosis of this condition there are no randomized controlled trials (RCT) investigating treatment options. Because of the apparent close relationship with social anxiety spectrum disorders, treatment has been based on SSRIs, TCAs and CBT. Studies have reported effectiveness for antidepressants including TCAs and SSRIs. However, these are case reports that make general recommendations tenuous at best [39, 43, 44, 45].


Even though these disorders are relatively uncommon, they are still seen with relative frequency in dermatology practice. Patients with these conditions pose a particular challenge to dermatologists and the time spent reassuring these pateints and evaluating their belongings for parasites or fibers can be quite significant. Because the best treatment options are centered on psychotropic medications and psychotherapy, mangement should involve a multi-disciplinary approach including both dermatologists and psychiatrists with a special interest in these patients.

Although the patients with the conditions described above are classically referred to as "delusional," the beliefs of some patients exist on a spectrum from obsession to delusion and, as such, some patients may at least temporarily, be convinced otherwise after counseling. An accepting, non-confrontational approach is more likely to be successful in forming an alliance with patients than confronting patients on their impaired reality testing. Using a gentle, supportive approach can allow a therapeutic relationship to develop and, hopefully, improvement will follow.


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