Transcript Delusions of Parasitosis/Psychocutaneous Disorders

Picking Apart Delusions of Infestation
J. Michael Bostwick, MD
Professor of Psychiatry
Mayo Clinic College of Medicine
Delusional Parasitosis
• Nosologically nonspecific
“DP is a nosologically unspecific syndrome which may
occur superimposed on all psychiatric disorders.”
Muzalak 1990
• Epiphenomenal bugs
– “DP is not restricted to any single diagnostic category
(as it was supposed in former times) but may be found
as a (sometimes even prominent) epiphenomenon in
a lot of different psychiatric disorders.”
Trabert 1995
Delusions of Infestation:
The Mayo Clinic Experience
• 147 Mayo patients, 2001-2007
– 123/142 (87%) seeking 2nd (or more) opinion
– F:M ratio: 2.89; mean age: 57 yrs
– 82/142 (56%) married
– 48/142 (33%) disabled; 16/48 (33%) from DI
Foster 2012
Delusions of Infestation:
The Mayo Clinic Experience
• Infestation composition
– 113/143 (79%) insects
– 39/143 (27%) worms
– 29/143 (20%) fibers
– 64/143 (45%) multiple
Foster 2012
Delusions of Infestation:
The Mayo Clinic Experience
• Initial presentation
– 20% ED
– 77% Derm, other medical specialties
– 3% Psychiatry
• Comorbid psychiatric conditions
– 119/147 (81%) prior psychiatric condition
– 38/147 (26%) shared delusion
Foster 2012
High Levels of Comorbidity
• 54 MC patients with Delusions of Infestation
– 109 referred to psychiatry; 54 (50%) went
• 24/54 (44%) depressive d/o
• 10/54 (19%) GAD, anxiety nos
• 10/54 (19%) drug abuse/dependence
• Other diagnoses:
– pain, somatization, psychosis, PTSD, panic, mania, etc
Hylwa 2012
To bx or not to bx…
• 108 Mayo Clinic patients, 2001-2007, with DI
– 80 biopsies
– 80 patient-submitted speciments
– 52 both
Hylwa 2011
Value Added?
• 0/80 biopsies supported skin infestation
– 49/80 (61%) dermatitis
– 38/80 (48%) excoriation, ulceration, erosion
– 25/80 (31%) nonspecific
• 0/80 submissions supported infestation
– 10/80 insects
• 9/10 non-infesting varieties
• 1/10 pubic louse
– 70/80 skin debris, env’l detritus, plant material
Hylwa 2011
DP Differential Dx
• Resembles primary skin condition differential
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Actual infestation
Vitamin B12 deficiency
Multiple sclerosis
Cerebrovascular disease
Schizophrenia
Psychotic depression
Drug-induced psychosis
Formication without delusions
Cocaine/amphetamine/alcohol withdrawal
Et cetera
Rule-out Diagnosis
“If any of these underlying causes are
diagnosed, a separate diagnosis of delusions
of parasitosis should not be made.”
Buljian 2005
• Case example
– Bury JE, Bostwick JM. Iatrogenic delusional
parasitosis: a case of physician-patient folie a
deux. Gen Hosp Psychiatry 2010;32:210-212.
Pre-Video Discussion
Patient Video (audio only)
Post-Video Discussion
Psychocutaneous Disorders
J. Michael Bostwick
Professor of Psychiatry
Mayo Clinic Rochester
Common Origins
“Derived as they are both from fetal ectoderm, it
is hardly surprising that interactions between
the skin and the nervous system are common.”
Koblenzer 2001
Three Traditional Categories
1) Psychosomatic/psychophysiologic
1) Primary psychiatric disorder with secondary
skin manifestations
1) Primary skin lesions induce secondary
psychiatric disorder
1) Psychosomatic/Psychophysiologic
• Dermatologic condition present
• Stress induces/exacerbates skin condition
• Examples:
– Acne, chronic urticaria, psychogenic purpura,
psoriasis, atopic dermatitis, rosacea, etc.
2) Primary Psychiatric Disorder
• Primary psychiatric condition present
• Psych condition compels self-induced skin injury
• Examples:
– Trichotillomania, factitial dermatitis, neurotic
excoriations, delusions of infestation, dysmorphobia,
etc.
Self-inflicted Skin Lesions: Two Types
• Neurotic excoriations
– Pt knowingly but uncontrollably creates lesions
• Response to itch/urge
• “cutaneous sign of psychopathology”
• Dermatitis artefacta
– Pt denies having made obviously self-inflicted lesions
• Malingering
• Factitious disorder
Koblenzer 2001, Gupta 1986
3) Primary Skin Condition
• Skin disease – dermatologic or systemic – manifests
in disfiguring skin lesions
• Lesions damage self-esteem, body image, leading to
humiliation, frustration, frank psych pathology
– Social phobia, depressive d/o, anxiety d/o
– Stigma dimensions: 1) rejection sensitivity; 2) feelings of
being flawed; 3) guilt & shame; 4) secretiveness
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• Examples:
– Dermatologic: vitiligo, cystic acne, hemangiomas, icthyosis,
Kaposi’s sarcoma, neurofibromatosis, etc.
– Systemic: endocrine, metabolic, hematologic malignant,
autoimmune conditions, etc.
Emotional Bidirectionality
“Emotional experience may be reflected in
changes in cutaneous function…. The
experience of chronic or disfiguring skin
disease may have a profound impact on the
emotional life of the individual.”
Koblenzer 2001
Etiological Bidirectionality
• Cognitive model
– Sensation influences perception
– Narrative explanation needed for perception
• Sensorial model
– Perception influences sensation
– How sensation is perceived affects experience of it.
• Both likely present to one degree or another
Pruritogens and their Antidotes
• Mediators facilitate direct or indirect histamine release
– Histamine – urticaria, atopic dermatitis
• Directly acts on H1 receptors, epidermal nerve endings
– Treat systemically with antihistamines, TCAs, systemic & topical
corticosteroids & newer immune modulators, cimetidine
– Treat locally with capsaicin, nonspecific symptomatic measures
– Endogenous opioids – atopic dermatitis, cholestasis,
hemodialysis
• Facilitate histamine release via increased opioidergic tone
– Treat with naltrexone, naloxone, nalmefene; cholestyramine,
rifampin (to bind and reduce bile acid uptake)
– Serotonin – uremia, cholestasis, polycythemia vera
• Facilitates histamine release
– Treat with ondansetron, cyproheptadine, pizotifen
Shaw 2007
Psychogenic Excoriation & Treatments
• Characterize subtype
– Compulsive
• Excoriation relieves obsessional anxiety/dread
• Pt has insight into senseless, harmful action tries to resist
• SSRIs
– Impulsive
• Excoriation causes arousal, pleasure, tension reduction
• Pt has minimal awareness of, insight into automatic action
• First and second generation antipsychotics
– Mixed
• Both compulsive and impulsive features
• SSRIs & antipsychotics
Shaw 2007
Monosymptomatic Hypochondriasis
• Tactile sensation meets interpretation
– “A primary abnormal tactile sensation with a secondary
delusional elaboration….”
de Leon 1992
• Two types of MH
– True delusions
• False perceptions about a stimulus
• Antipsychotic-responsive
• Low-dose pimozide, risperidone, aripiprazole
– Obsessive-compulsive
• Intrusive, uncontrollable worry about possible abnormality
• SSRI-responsive
Koblenzer 2010
In touch but out of touch…
“The patient who presents to us with
dermatologic symptoms is frequently not in
touch with his or her feelings: the patient is
unaware of any underlying psychic distress
and focuses only on the skin.”
Koblenzer 2001
Alternate Explanation
• The Problem: Cutaneous Sensory Disorders
• Burning, stinging, crawling, pain etc. in absence of primary
skin d/o, identifiable underlying medical/neurologic
condition
• Treatments – neither topical nor systemic tx usually helps
• Hypothesis #1: “The patient’s crazy.”
– comorbid affective, personality, or behavioral d/o
causes the problem.
• Hypothesis #2: Gawande’s Analogy
– Efferent messages from brain create disease process.
Sensor Malfunction Syndromes
• Alternate explanation for DP-like conditions
• Gawande’s analogy
– Car sensor goes off, dashboard warning signal lights up
• Mechanic looks for engine failure, finds nothing wrong
• Explanation: faulty sensor
– Pt reports pain, itch, nausea, fatigue, etc. – normally
“warning signals” of disease
• Physician assumes tissue or nerve problem
• Lab tests, imaging, nerve-testing, etc. find no anatomic or
physiologic explanation for “engine failure”
• Explanation: pt is “crazy”
Gawande 2008, Elpern 2009
Careful workup
• Look for underlying derm or medical disorder
– Treat cause of primary skin condition
– Reevaluate psychiatric symptoms, treat prn
• Characterize nature of psychiatric symptoms,
if present, to guide treatment
– Compulsive
– Impulsive
– Mixed
• Be non-judgmental, be patient, be humble.
Wise Words
“My own approach has been to explain to the
patient that from my examination, biopsy, and
tests, I have been unable to find evidence to
support any of the possible causes put forth
by the patient… though I in no way doubt the
patient’s experience. I explain that though we
cannot explain exactly what I going on, we
believe that in part, certain neuropeptides are
involved.”
Koblenzer 2006
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Bibliography
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General Hospital Psychiatry 2011;33:533-534.
Bury JE, Bostwick JM. Iatrogenic delusional parasitosis: a case of physician-patient folie a deux. Gen Hosp
Psychiatry 2010;32:210-212.
de Leon J, Antelo RE, Simpson G. Delusion of parasitosis or chronic tactile hallucinosis: hypothesis about their
brain physiopathology. Comp Psychiatry 1992;33:25-33.
Elpern DJ. Toward a better understanding of “psychocutaneous disorders”. International Journal of Dermatology
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Foster AA, Hylwa SA, Bury JE, Davis MDP, Pittelkow MR, Bostwick JM. Delusional infestation: clinical presentation
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