delusional parasitosis in dermatological practice

JEADV ISSN 1468-3083

462

© 2007 The Authors

JEADV

2007,

21

, 462–465 Journal compilation © 2007 European Academy of Dermatology and Venereology

Blackwell Publishing Ltd

ORIGINAL ARTICLE

Delusional parasitosis in dermatological practice

JC Szepietowski,*† J Salomon,† E Hrehorów,† P Pacan,‡ A Zalewska,§ A Sysa-Je

drzejowska§

Departments of †Dermatology, Venereology and Allergology and ‡Psychiatry, University of Medicine, ul. Chalubinskiego 1, 50-368 Wroclaw, Poland and

§Department of Dermatology and Venereology, Medical University, Lodz, Poland

Keywords

delusional parasitosis, frequency,

treatment modalities

*Corresponding author,

tel. + 48 717842288; fax + 48 717840942;

e-mail: [email protected]

Received: 28 November 2005,

accepted 2 May 2006

DOI: 10.1111/j.1468-3083.2006.01900.x

Abstract

Background

The accurate incidence of delusional parasitosis (DP) is difficultto assess. The aim of this study was to analyse the frequency of DP treated bydermatologists, and to evaluate the treatment modalities they applied.

Material and methods

A specially designed questionnaire was distributed to172 dermatologists. A total of 118 doctors responded (68.6% of all subjects).The dermatologists were asked to answer questions concerning demographicdata of the respondents and the frequency of DP observed in their everydaypractice. Finally, methods of treatment used by the dermatologists to helppatients suffering from DP were evaluated.

Results

During the whole working period the majority of dermatologistsparticipating in the survey (84.7%) had seen at least one patient with DP in theirpractice. About one-third of the respondents (33%) had seen one or two cases ofDP during the past 5 years, and 28% of the doctors treated from three to five suchpatients. Twenty-three per cent of dermatologists declared that they haddiagnosed no cases of DP during the past 5 years. The rest of our respondents hadseen more than five cases of DP during the past 5 years, and 7% of the doctorsreported seeing more than 10 patients with DP within this period. Almost 20% ofthe dermatologists were currently treating a patient with DP. Our data show that40.7% of the respondents always ask and 28.8% often ask for a psychiatricopinion about their patients with DP. More experienced dermatologists statisticallymore frequently (

P <

0.05) obtained a psychiatric opinion about their patients.Only a small group of dermatologists (15.3%) use their own pharmacologicaltreatment. If they do so, they first use sedatives and anxiety-relieving drugs.

Conclusion

DP is a quite common disorder, however not all dermatologistsare sufficiently prepared to treat it. There is an urgent need for training on thedermatological approach to psychodermatoses.

Introduction

Delusional parasitosis (DP) is a form of monohypo-chondriacal psychosis. It is a psychiatric condition inwhich patients have a strong but false belief of beinginfested by skin parasites.

1,2

An accurate incidence of DPis difficult to assess because the epidemiological data arevery limited. In 1988 it was reported that DP was diagnosedin about seven of 10000 psychiatric admissions.

3

However,the incidence of this disorder is probably much higherbecause most cases of DP are treated by dermatologistsand the prevalence of the disease reported by psychiatrists

may be underestimated. The disease usually occurs aftermiddle age in subjects over the age of 45 years,

4–6

andsome authors claim that it is more frequently reported inwomen.

4,5,7,8

Two variants of DP have been distinguished.Primary DP is not due to any other underlying disorder. Asecondary variant of the disease develops in the course ofother psychiatric conditions such as schizophrenia, depres-sion and dementia. It is also common that DP coexistswith various physical disorders, such as diabetes mellitus,renal insufficiency, hepatitis, vitamin B

12

deficiency, multiplesclerosis or leprosy. In most of these conditions pruritus orother skin sensations are also frequent symptoms. DP may also

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be induced by drugs, for example amantadine, anticholinergicagents, levodopa, or occasionally by some antibiotics.

4,5,9,10

The clinical picture of DP is very characteristic and thecondition is easy to diagnose. The most important symp-tom is the complaint of crawling, biting or burrowinginsects. Patients usually give a very detailed description ofthe parasites and their behaviour, and most of them spenda lot of time, money and effort to get rid of the bugs. Theyperform obsessive purification rituals that frequently leadto self-mutilation, they apply disinfectants or pesticides tothe skin, and they often scratch themselves and try to takeout the parasites. Very typical is the so-called ‘matchboxsign’, which involves bringing to the doctor samples ofthe parasites that are in fact small parts of the patient’sskin.

11,12

Many patients suffering from DP have a fear ofcontaminating other people, especially members of theirfamily, and perform various preventive actions. The skinsensations felt by DP patients often result in chronicinsomnia. Skin changes are usually present on the trunk,scalp and hands.

5

Scratch excoriations, lichenification orirritant contact dermatitis symptoms are frequently observed.

Patients with DP initially go to a dermatologist becausethey are convinced they have a skin disease.

9

Most patientsreject any psychiatric help, expecting the dermatologistto solve their problems. Because of this we decided toevaluate how dermatologists in our country deal with theproblems of DP, a strictly psychiatric condition. Therefore,the aim of this study was to analyse the frequency of DPpatients treated by Polish dermatologists, and to evaluatethe treatment modalities they applied.

Materials and methods

A specially designed questionnaire was distributed to 172dermatologists in two regions of Poland: Lower Silesia andcentral Poland. A total of 118 doctors responded (68.6%of all subjects). Among this group there were 95 womenand 23 men. Their duration of employment varied from1 year to 52 years. The workplace of the dermatologistsparticipating in the study were numerous: 33% of therespondents worked in the hospital on dermatology wards,30% worked in outpatient clinics, 11% had their ownpractice and 23% worked in more than one workplace.

The dermatologists were asked to answer the question-naire, which contained questions concerning demographicdata of the respondents and frequency of observed DP intheir everyday practice. Separately, the frequency of DPpatients seen by the dermatologists was assessed for thewhole working period, for the past 5 years, and for thecurrent period. Finally, methods of treatment used bythe dermatologists to help patients suffering from DP wereevaluated. Statistical analysis was performed using the

χ

2

-test.

P

-values less than 0.05 were considered significant.

Results

During the whole working period the majority of derma-tologists participating in the survey (84.7%) had observedat least one patient with DP in their practice. Only 15.3%of our respondents had never diagnosed such a disorder.About one-third of the respondents (33%) observed oneor two cases of DP during the past 5 years, and 28% of thedoctors treated from three to five such patients. Twenty-three per cent of dermatologists declared that they haddiagnosed no cases of DP during the past 5 years. Therest of our respondents saw more than five cases of DPduring the past 5 years, and 7% of the doctors reportedseeing more than 10 patients with DP within this period.Almost 20% of dermatologists were currently treatinga patient with DP. The data are presented in Table 1 andfig. 1.

Dermatologists participating in the survey often ask fora psychiatric opinion about their patients with DP. Ourstudy showed that 40.7% (48 subjects) of the respondentsalways ask and 28.8% (34 subjects) often ask for a psych-iatric opinion. Only 17.8% (21 subjects) of dermatologistsrefer the patient with DP to the psychiatrist occasionally,and 12.7% (15 subjects) never do but try to treat the patient

Table 1 The frequency of DP patients observed by dermatologists

participating in this study over the whole working period, in the past 5

years and in the current period (n = 118)

DP patients observed

Dermatologists participating in the study, n (%)

Whole working period

Past 5 years

Current status

Yes 100 (84.7) 91 (77.1) 23 (19.5)

No 18 (15.3) 27 (22.9) 95 (80.5)

fig. 1 Percentage of dermatologists treating various numbers of DP

patients during the past 5 years.


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by themselves. More experienced dermatologists (withlonger working period) statistically more frequently (

P <

0.05) obtained a psychiatric opinion about their patients(detailed data not shown).

Various treatment strategies were used by the derma-tologists. Most often (38.1%), dermatologists try to obtaina psychiatric opinion and then treat the patient withDP according to the psychiatric advice. About 27% of therespondents always refer such a patient to the psychia-trist. Many dermatologists (19.5%), as the only method oftreatment, try to talk to the patient and patiently explainthe reasons for the disease. Finally, a small group ofdermatologists (15.3%) use their own pharmacologicaltreatment. If they do so, they initially use sedatives andanxiety-relieving drugs. Other pharmacological methodsused by dermatologists are: placebos, antipruritics, antide-pressants and antipsychotic agents. The data concerningtreatment modalities are illustrated in figs 2 and 3.

Discussion

Patients suffering from DP have a false belief that theirskin is infested by insects. Although this is typically apsychiatric disorder, patients usually go to a dermatologistbecause they are strongly convinced that they have a skinproblem that has to be resolved by a skin diseases specialist.Therefore, all dermatologists should be familiar with thiscondition. Treatment of DP may be very difficult as mostpatients reject any psychiatric help. The main difficulty isconvincing the patient to take a drug. It is generally easierfor a patient to accept pharmacological treatment prescribedby a dermatologist than by a psychiatrist. That is the reasonwhy dermatologists usually treat such patients.

The aim of this study was to assess the frequency of DPobserved by dermatologists and to evaluate how they dealwith this disorder. According to our findings, DP is not asrare a condition as it seemed to be. The majority of

dermatologists (85%) had seen a patient with DP in theirpractice, and about one-fifth of the respondents werecurrently treating such a patient. Accurate data aboutthe frequency of DP in Europe and in the world are notknown. Most often DP is presented as a case report or fora small sample of patients, and epidemiological data aredifficult to obtain and very limited. Sheppard

et al

.

13

reportedeight patients with DP during 3 years of clinical practice,and most of our respondents (77%) had seen betweenone and five patients with DP during the past 5 years.

There are few reports concerning the dermatologists’experience with patients suffering from DP. Reilly andBatchelor

14

established in a postal survey that dermatologiststreated the disorder effectively, especially when neurolepticswere used. Few patients were successfully referred topsychiatrists. This is in agreement with other reports, withmany authors focusing on the difficulties encounteredin persuading the patient to visit a psychiatrist.

7,11

Ourrespondents relatively frequently (65%) referred the patientto a psychiatrist or at least tried to obtain a psychiatricopinion about the patients; however, we do not knowhow many of them accepted the help of the psychiatrist.Fifteen per cent of dermatologists treated the patients bythemselves but were cautious about prescribing neuroleptics.Most dermatologists managing the patients with DP with-out psychiatric advice did not use the first-choice treatment.

Because patients with DP generally seek care from skinspecialists and refuse psychiatric referral, dermatologistsare usually responsible for managing this group of patients.The frequency of DP is relatively high, and all dermatologistsare likely to meet such a patient in their clinical practice.According to our data, dermatologists are not sufficientlyprepared to treat patients with DP successfully. There is anurgent need for special training in presenting the derma-

fig. 2 Procedures used by dermatologists in patients with DP.

fig. 3 Pharmacological treatment used by dermatologists in patients with DP.

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tological approach to psychodermatoses. The courses fordermatologists should be based on theoretical knowledgeabout psychodermatoses and antipsychotic treatment aswell as practical skills of talking to such patients. Liaisonbetween dermatologists and psychiatrists is essential.

The first step in the management of a patient with DPshould be to exclude any organic skin pathology. All theunderlying systemic diseases should be properly treated.Evaluation of quality of life impairment may be helpful inassessing the severity of the disease. Referral of the patientto psychiatric care should be considered. If this is notpossible or the patient refuses any psychiatric help, phar-macological treatment should be given. Neuroleptics suchas pimozide are considered as the treatment of choice.

15–18

Pimozide is an antipsychotic agent that has a dopaminergiceffect and blocks opioid receptors. It should be started ata dose of 1 mg daily and then the dose should be increased.In most cases a daily dose of 4–6 mg is sufficient for treat-ment of DP. This treatment is sometimes associatedwith side-effects. The most common adverse effects areextrapyramidal side-effects (EPMS). The symptoms ofEPMS are stiffness and akathisia (feeling of restlessness,foot tapping and inability to sit quietly).

17

Other possibleside-effects are repetitive stereotyped movements. Pimozidealso has the potential for cardiac toxicity by prolongingthe QT interval and causing ventricular arrhythmia.

17,18

Electrocardiographic monitoring is recommended in patientswith a history of cardiac disorders. The new neurolepticsare the alternative treatment of DP. This therapy is associatedwith a lower risk of EPMS. Risperidone has been reportedto be effective in the treatment of DP.

19–21

The side-effectsof risperidone may be anxiety, dizziness and rhinitis, andalso sedation and fatigue. This drug may also cause cardiacarrhythmia. Other atypical neuroleptics are olanzapine,which can cause sedation, anticholinergic effects and weightgain, and quetiapine, which can cause mild somnolenceand orthostatic hypotension.

17,18

The benefits and risksof newer antipsychotics in the treatment of DP need to befurther evaluated. There is also the possibility of givingdepot neuroleptic therapy with flusperilen. This therapyrequires injections at regular intervals and there arefavourable reports about the clinical effects of this treat-ment in patients with DP.

22

In some cases antidepressantsgiven additionally may be beneficial.

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