Indirect Effects – “Mystery Bites” Announcements Speaking Today: Shea Gatewood Speaking Next...

Indirect Effects – “Mystery Bites”

AnnouncementsSpeaking Today: Shea GatewoodSpeaking Next Thursday: Angela JonesNext Quiz??

Quiz Review

• 1. – a. American Dog Tick– b. Male– c. Rickettsia, overwinters in the ticks

• 2: C, B, D• 3: D• 4: C• 5: B• 6: E• 7: Allergies

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Psychological Effects

• “Illusional” Parasitosis = “Invisible Itches”– Incorrectly ascribing a real medical response

to an arthropod cause

• Entomophobia/Arachnophobia– Persistent irrational fear of insects/arachnids

• Delusional Parasitosis– Unshakable false belief that live arthropods

are on/in the skin.

“Invisible Itches”

• Actual irritation whose source cannot be identified by the patient– Arthropod sources

• Allergen sources such as dust mites• Biting arthropods (bed bugs, fleas, mites, etc.). Generally

delayed reaction.– Non-Arthropod Sources – Environmental

• Physical– Temperature/humidity changes– Fibers (paper, fabric) – NOT Morgellon’s Syndrome– Electrical (esp. static).

• Chemical– Household products (esp. fabric detergents & related)– Solvents or other volatiles

Entomophobia/Arachnophobia

• Subgroup of zoophobias• 3 Characteristics

– Perisistent irrational fear of insects.– Significant distress in patient who is also aware that

the fear is unreasonable.– Not due to other mental/physical disorder (e.g.

obsessive/compulsive order, schizophrenia, etc.).

• Phobic object may be insects in general, a single group of insects, or infestation by real/imagined insects.

Delusional Parasitosis (DP)

• Patient experiences state of being infested, not the fear as in phobias.

• Described by Ekbom (1938) who also described Restless Leg Syndrome. Both carry his name.

• Experience can involve all senses• Categorized as a “Non-Bizarre Delusional Disorder” in

diagnostic manuals.• Two kinds

– Primary – DP is the entity itself– Secondary – DP is a symptom of a superior psychiatric condition

• Functional – Clinical depression association• Organic – Chemically-related

Delusional Parasitosis Presentation

• Elaborate description of parasites

• Ritualistic purifications• Obsessive self mutilation• Excessive application of

insecticides/creams to skin• “Matchbox sign”• Delusional infestation may be

shared (or believed to be shared) by other family members

Primary Delusional Parasitosis

• No other symptom or deterioration in mental/psychiatric state.

• AKA “monosymptomatic hypochondriacal psychosis” or “true DP”

• Most common in Caucasian women, >90% of these are > 40 years old.

• Prevalence greater among less educated, lower income population.

• Long-term treatment with psychotropics generally indicated.

Secondary DP

• Much more common than Primary DP• Epidemiologically increases during time of social

stress.• A reaction to a primary problem (e.g. drug

abuse)– Treatment generally targets the primary problem.

• Patient is generally aware that the sensation is delusional (unlike primary).– Generally more easily convinced to see a mental

health professional

Secondary DP Examples• Formication and visual

hallucinations secondary to methamphetamine abuse resulted in the self-infliction of these papular and scabbed lesions. The patient believed that “bugs” were in her skin.

• In addition to her face, she had lesions on her arms, shoulders, and neck. She had a history of methamphetamine use, which was concurrent with her alleged infestation.

• “coke bugs,” “meth mites,” and “amphetamites”

Secondary DP Examples

• The patient complained of a worm infestation in his neck. He used a pair of scissors to excise the imagined worms.

• The toxicology screening of this patient was positive for cocaine, opiates, and benzodiazepines.

Secondary DP Examples• Middle-aged woman presenting

with excoriated papules and scarring on the arms and back (not shown). Believed that she was infested with “skin mites.”

• Scarring is a telltale sign of chronicity.

• Neurotic excoriations generally are caused by the patient’s fingernails; they have a uniform disciform size and shape & are located in accessible parts of the body.

DermatologicInsect bite reaction or infestationChronic folliculitisDermatitis herpetiformisPsychiatricSchizophrenia spectrum disordersAffective disorders with psychotic featuresAnxiety disorders, particularly obsessive–compulsive disorderHematologic/OncologicSevere anemiaLymphoproliferative disorders, lymphomaMyeloproliferative disorders, multiple myelomaBreast cancerMetabolicUremiaCholestasisCarcinoid syndromeEndocrineDiabetes mellitusHyper- or hypothyroidismHyper- or hypoparathyroidism

Substance abuseCocaineAmphetaminesAlcohol withdrawal (DTs)InfectiousAIDSHepatitisSyphilisTuberculosisMeningitis/EncephalitisNeurologicNeuropathiesParkinson's diseaseHuntington's diseaseMultiple sclerosisCerebrovascular accidentTraumatic brain injuryDementia

Some Reported Causes of Secondary DP. Source: Bury & Bostwick (in press)

Related Conditions

• Delusory cleptoparasitosis -- sufferer believes the infestation is in their dwelling, rather than on/in their body.

• Formication – Sensation of stinging, crawling, biting on skin but patient knows that it is not caused by arthropods.

• Morgellon’s Syndrome– Sensation of crawling/biting believed (by patient) to be

caused by fibers.– New description (2004), not universally accepted.– Morgellon Research Foundation has a case definition.

How to Handle “Mystery” Bites: First, look.

• Treat all bite complaints as legitimate.• Biting pests are never invisible to you• There are no “paper mites”, “cable mites”• Inspect “bite” area, collect any specimen. • Dab area with damp cotton, deposit in

alcohol. Dab area with tape, place on paper. Send in for analysis.

• Pest control provider can install traps or other monitoring devices

How to Handle “Mystery” Bites: If Nothing is Found

1. Person may be being bit in some other location.

2. Suspect skin condition (many look & feel like bites), refer to dermatologist

3. Suspect environmental condition (static, chemicals, etc.). Refer to industrial hygenist

4. May be delusory parasitosis. Recruit assistance.

Proceed in the following order