Infestations and Bites - Healthcare Professionals

Bites and Infestations
David F. Butler, MD
Professor and Chair
Department of Dermatology
Scott and White Healthcare
Temple, Texas
No Conflicts of Interest
Delusions of Parasitosis
Audience Response Question
Under DSM IV, delusions of parasitosis is
classified as:
1.
2.
3.
4.
Neurosis
Personality disorder
Depressive disorder
Monosymptomatic psychosis
Delusions of Parasitosis
(Ekbom’s syndrome)
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Fixed false belief that “bugs” infest the skin
Focal psychosis, patient remain functional
F>M
Bimodal age distribution: 20-30 & >50
Occasionally associated with depression, true
psychosis or drug use
• Formication: “crawling” sensation
• PE: excoriations or no skin lesions
Evaluation of patients with diffuse
pruritus without primary skin lesions
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CBC, serum B12, folate, Fe studies
CMP (renal, liver, calcium, glucose)
Thyroid
HIV
Hepatitis profile
Urine drug screen
Chest X-ray
Skin biopsy with IF
Age appropriate cancer screen
Complete skin exam
Match Box Sign
• Patient collects pieces of
scabs, dirt, vegetation,
debris, hair, insects
• Presents them as
“evidence”
• Placed in kleenex, bottle,
glad bag or match box
• Carefully observe and
document with
magnification
Folie a deux
• Spouse, family members or close friends may
hold misguided belief that patient is “infested”
• They can also “see” the bugs and aid in
collection
• Family may contribute to the problem
• Patient and family members often more
concerned about “proving” diagnosis than
getting better
Management
• Develop a constructive interpersonal relationship
with patient and family
• Rule out organic disease
• Refer to psychiatrist or dermatologist interested
in this condition (Jason Reichenberg MD, UT
Southwestern Austin)
• Start an anti-psychotic medication
Medications
• Risperidone (0.5mg titrate up to 2mg) potential for weight
gain, hyperprolactinemia, 67% complete or partial
remission
• Olanzapine (2.5 mg titrate up to 10mg) risk of metabolic
syndrome-wt. gain, hyperglycemia and increased lipids
• Pimozide: (0.5mg titrate up to 2 mg) potent older antipsychotic, 94% complete or partial remission, risk of
extrapyramidal side effects, prolongation of QT interval
(follow EKG), drug interactions (SSRI, antibiotics,
antifungals)
Morgellons Disease
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Cutaneous dysesthesias
Exudative, excoriated skin lesions
Fixed belief that “fibers” are the cause
Disorder dominates their lives
Quasi-scientific support
National organization with website (Morgellons
Research Foundation)
• Some respond to oral antibiotics
• CDC found no “infectious” cause
• Empathize, acknowledge sensations, treat
symptoms, antipsychotics or refer
Morgellons Fibers
Audience Response Question
Which is true of “crusted” scabies:
1.Easily distinguished from psoriasis
2. Usually responds to treatment with topical
permethrin
3. May require use of topical keratolytics in
addition to oral ivermectin
4. Only a few mites are present in the skin
Scabies
• Sarcoptes Scabiei
var. hominis
• Obligate human
parasite
• Transmission via
direct contact or
fomites
• Incubation period
7-30 days
© 2004 Elsevier
Clinical features
• Nocturnal pruritus
• Papules on hands, wrists, axilla, breasts,
genitalia and feet
• Infants and elderly may have head and
neck involvment
• Burrow: wavy fine white line on pink
papule-tunnel with mite and eggs
Crusted Scabies
• Thousands of mites
building “condos”
• Immunocompromised
• Down’s syndrome
• Neurologic disoders
• Dementia
• HIV
Diagnosis
• Demonstration of
mite, eggs or
scybala
• Skin biopsy
• Dermoscopy
Histopathology
Dermoscopy of burrow
Treatment
• Wash all night clothes, linens and towels
after treatment in hot water
• Repeat therapy at one week
• Treat all household contacts at the same
time (usually evening)
• Post-treatment pruritus may be treated
with antihistamines and topical steroids
Permethrin Cream 5%
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Well tolerated
May be used in 6 month olds
May be used in pregnancy
Apply from neck to toes at HS, repeat in
one week
• Some signs of resistance
Lindane
(gamma benzene hexachloride)
• Not commonly used
• Apply neck to toes at HS repeat in one
week
• Excessively absorbed by damaged skin
• CNS toxicity (seizures)
• Cannot use in children < 2 yrs, pregnant
women, breast-feeding
• Less effective than permethrin and
ivermectin
Ivermectin
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Not FDA approved indication
Blocks neurotransmission in mite
Avoid in children < 15 kg
Does not cross BBB in adults
Very safe
200-400 micrograms/kg (12 mg) orally,
repeat in one week
• Very helpful for crusted scabies and in
“nursing home” settings
Audience Response Question
Which of the following is true concerning bedbugs:
1. Bedbugs are known vectors of infectious
diseases such as hepatitis and HIV
2. Topical therapy with permethrin cream is
effective
3. The incidence in large city hotels is declining
4. A characteristic clinical feature is the presence
of red papules in a row (“breakfast, lunch and
dinner”)
Bedbugs
• Cimex lectularis/
hemipterus
• Blood suckers
• Feed on humans,
bats, chickens, birds
• Noctural
• Live in cracks and
crevices of furniture,
beds, headboards,
window sills
Bedbugs
• Incidence increasing
especially in large
cities
• Bites are painless
• Red papules develop
in a row: “breakfast,
lunch and dinner”
• No known
transmission of other
illnesses
Bedbug treatment
Bites treated with
topical corticosteroids
and antihistamines for
itch
Furniture and/or
bedding should be
sanitized or steamed
Pesticides applied to
affected furniture,
bedding
Audience Response Question
Which of the following topical treatments for
head lice are ovicidal (kill nits)?
1.Permethrin
2.Malathion
3.Benzyl Alcohol
4.Spinosad
5.Topical ivermectin
Head Lice
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Pediculosis capitis
12 million cases per year in U.S.
Obligate human parasite
Feeds every 6 hours
Eggs on hair shaft= nit
Transmission by direct contact, combs,
brushes, hats, helmets, furniture
• Very rare in African Americans
Head Lice
• Scalp pruritus
• Dx: seeing lice or nits
• Excoriations,
erythema, pyoderma
• Female lives 30 days
• Lays 5-10 eggs/day
• May transmit staph.
aureus or strept
Treatment
“Older” topicals require
physically remove nits
Wet comb hair (vinegar
water) with fine toothed
comb
Eliminate fomites
Repeat topical treatment in
one week
Not effective Rx: petrolatum,
mayonaise, olive oil,
Bactrim
Topical Treatments
Permethrin 1% cream
rinse (OTC)- apply 10
min to clean dry hair
Only moderately
effective, resistance
Permethrin cream 5%,
apply overnight
Moderately effective,
resistance
Topical Treatment
• Malathion (Ovide lotion): applied 20
minutes to dry hair more effective than
permethrin (not ovicidal)
• Benzyl Alcohol (Ulefsia) 5% lotion:
asphyxiates lice by paralyzing respiratory
spiracles, applied for 10 minutes repeat in
one week (not ovicidal), use > 6 months,
OK during pregnancy
Newer Topical Treatment
• Spinosad (Natroba) 0.9% cream rinse:
applied 10 min to dry hair then shampoo,
neurotoxic to lice, use > 4 years of age,
ovicidal-kills nits!
• Topical ivermectin (Sklice) 0.5% lotion:
one 10 min application, rinse with water
ovicidal-kills nits! Use> 6 months of age
Oral Treatment
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Oral ivermectin: 200-250 micrograms/kg
Use on days 1 and 8
Highly effective
Cannot use in children < 15 kg or pregnant
or breastfeeding women
Crab Lice
• Pthirus pubis
• “Crab” rather than
“pubic” louse
• STD
• Fomites: clothing,
bedding
• Pubic area, scalp,
eyelashes, axilla,
beard
Crab lice: clinical features
Eyelash nits
• Pruritus, excoriations
• Lymphadenopathy
• Macula caerulea: pubis,
trunk, thighs-slate gray or
blue macules .5-1cm
Crab Lice Treatment
• Permethrin cream
rinse 1% (OTC)
• Permethrin 5% cream
• Oral ivermectin 200400 micrograms/kg
Repeat treatment in one
week
Audience Response Question
Which of the following are true regarding
Botfly Myiasis:
1.Commonly reported in the Southern U.S.
2.The fly lays the eggs directly on the skin
3.The lesion does not look like a furuncle
4.One treatment method is to use raw meat
(beef, bacon) to draw the larva out of the
skin
Furuncular Myiasis
• Dermatobia hominis (human botfly)
• Endemic to tropical Mexico, South
America, Central America, Trinidad
• Uncommon in the United States
• Travel related infestation
• Self-limited with minimal morbidity
Clinical Findings
• Erythematous papule(s) or
nodule(s)
• Open punctum
• Initial look –furuncle
• Close inspection –
– Pulsation at punctum
– Clear fluid/bubble at punctum
Dermatobia hominis (human
botfly)
Life Cycle
Treatment
Reduction of pain/discomfort
Psychologic relief
Options:
– Surgical excision with punch under local anesthesia
– Entice movement out of skin with raw meat
Prevention when traveling:
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Cover skin
Treat outer clothing with permethrin repellent
DEET to exposed skin
Permethrin-treated bed net
Audience Response Question
Regarding Black Widow Spider bites:
1.The local reaction is more serious than the
systemic reaction
2.The systemic reaction may mimic an
“acute abdomen”
3.The red hourglass is located on the back
of the spider
4.It is important to give antivenin in all cases
Black Widow Spider
• 5 widow species in North
America
• US:2500 bites/year- 4
deaths
• Latrodectus Mactans
most common
• Red hourglass on abd
• Woodpiles, outhouses,
garages
• Protects egg sack
• Acute pain/edema a bite
site
Black Widow Spider
• Systemic symptoms:
may mimic acute abd
• Neurotoxin: increases
intracellular calcium,
release of
neurtotransmitters
Symptoms
• One hour after bite:
– Muscle cramping- abdomen, chest, thighs
– Nausea and vomiting
– Headache, diaphoresis
– Anxiety
– Hypertension/tachycardia
– Facial swelling and muscle spasm
Treatment
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Supportive: IV fluids
Pain relief: nacotics
Benzodiazapines for spasms
Intravenous calcium gluconate no longer
recommended
• Tetanus immunization
• Antivenin for severe cases
Audience Response Question
Which of the following should NOT be
considered in the differential diagnosis of a
brown recluse spider bite:
1.Varicella zoster
2.Pyoderma Gangrenosum
3.Coumadin necrosis
4.Keratoacanthoma
5.Calciphylaxis
Brown Recluse Spider
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Loxosceles reclusa
“Fiddle back spider”
Small body, long legs
South central US,
Texas, Oklahoma
• Severe dermonecrotic
reactions
• Systemic reaction:
shock, hemolysis,
renal failure, DIC,
rhabdomyolysis
Pathogenesis
• Sphingomyelinase D interacts with serum
amyloid protein
• Hyaluronidase allows dependent spread of
toxins
• Coagulation necrosis
• Band of surrounding neutrophils
• Vasculitis
• Formation of eschar
Signs and Symptoms
• Severe pain
• “red, white and blue”
sign
• Progressive central
necrosis with
formation of eschar
• Fever, chills,
morbilliform rash and
arthralgias
Signs and Symptoms
Differential diagnosis:
Pyoderma
gangrenosum
Varicella Zoster
Pyoderma/MRSA
Vasculitis/vasculopathy
Coumadin necrosis
Calciphylaxis
Treatment
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Optimal treatment remains elusive
Ice, rest, elevation
Systemic antibiotics
Gentle wound care
Hyperbaric oxygen
Antivenin helpful in animal studies
Not helpful: dapsone, colchicine,
diphenhydramine (Benedryl) and
intralesional triamcinolone
• Oral prednisone for systemic effects
Hobo Spider
• Large, hairy
“aggressive” house
spider
• “Funnel Web Spider”
• Tegenaria agrestis
• Northwestern US
• Found in moist, cool
areas like basements
• Causes severe local
necrosis
Signs and Symptoms
• Pain
• Erythema, blistering
• Superficial ulceration
and necrosis
• Fever, arthralgias,
HA, rash
Treatment
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Pain relief
Systemic antibiotics
Local wound care
Systemic steroids for
severe reactions