Transcript Document

Parasitic Infestations,
Stings & Bites
Part 2 - Another SpineTingling Lecture from…
KCOM/TX Dermatology Residency
Consortium
Dan Ladd DO
Loaiasis
Aka Loa Loa, Calabar Swelling,
Fugitive Swelling, Tropical Swelling
Asymptomatic localized subQ
swellings, size of a hen’s egg
Prediliction for loose tissues such as
eyes, frenulum of tongue, genitalia
Mango fly Chrysops dimidia or silacea
Tx: Diethylcarbamazine
Loaiasis
Onchocerciasis
River Blindness
Central & South America, Mexico
Pretibial depigmentation: leopard
skin
Thickened skin: elephant skin
May develop into subQ nodules
Mazzoti test + if edema, pruritis,
fever & arthralgias w/ 50mg
diethylcarbamazine
Tx: Ivermectin 150mg single dose
Black fly Simulum
Leopard skin, Elephant skin
Trichinosis
Inadequately cooked pork, bear or
walrus meat
Puffy eyelid edema, red conjunctiva
and sometimes urticaria, fever, HA,
muscle pains, neurologic S&S.
20% have maculopapular rash, very
itchy, responsive to corticosteroids.
Diagnosis by muscle biopsy
Tx: Albendazole 400mg bid for 2w.
Trichinella spiralis – muscle bx
Phylum Arthropoda
Myriapoda
Centipede
Millipedes
Insecta
Caterpillar
Moth
Arachnidia
Myriapoda – Centipede Stings
Paired hemorrhagic puncta with
erythematous swelling progressing to
brawny edema or lymphangitis and
lymphadenopathy.
Scolopendra species, 15-20cm
Tx: Rub with garlic, local anesthetic
injection.
Scolopendra sp.
Myriapoda – Millipede burns
Millipede bodies secrete a toxic liquid
that causes brown discoloration,
progresses to erythema &
vesiculation – intense stinging and
burning pain
Tx: wash site immediately, topical
steroids.
Lepidoptera – Caterpillar Dermatitis
Nettling hairs contain toxin producing
local pruritic erythematous macules
and wheals.
MC campers, children playing in trees
and lumberjacks in Fall.
Nygmia phoerrhoea (brown-tail moth)
Megalopyge opercularis (puss)
Sibine stimulae (saddleback)
Megalopyge crispata (crinkled flannel)
Tx: Antihistamines, resolves 48 hours.
Saddleback
Brown tail moth
Lepidoptera – Moth Dermatitis
Hairs of the moth – urticating toxin
Euproctis chrysorrhoea (brown tail)
Cossus cossus (goat)
Dicranura vinula (puss)
Lymantria dispar (gypsy)
Hemenocampa pseudotsugata
(Douglas fir tussock)
Tx: oral steroids help, lasts 1 week
BROWN TAIL MOTH
GOAT MOTH
GYPSY MOTH
DOUGLAS FIR
TUSSOCK
Hemiptera – Bedbug Bites
Aka Cimicosis, Cimex lectularis
Smelly parasite with non-functioning wings.
Hides in crevices by day and feeds on
human blood at night.
“Breakfast-Lunch-Dinner” linear bites
Sensitivity at site due to saliva
Hepatitis B surface antigen has been
repeatedly demonstrated in the bugs, but
transmission is controversial
Tx: Pt: topicals, House: call exterminator.
Hemiptera – Reduviid Bug Bites
Aka Kissing Bug, Assasin bug,
conenoses
Attack face when asleep, bite is
painless, bug defecates and rubs
feces into wound, spreading
Trypanosoma cruzi
Chagas Disease
Anoplura
Pediculosis (Phthiriasis)
Pediculosis Capitis
Pediculosis Corporis
Pediculosis Pubis (Crabs)
Pediculosis (Phthiriasis)
Pediculus humanus (head & body)
Phthirus pubis (pubic or crab louse)
Attach and suck blood, saliva is
antigenic and creates dermatitis
Lice may transmit endemic typhus,
relapsing fever or trench fever.
Pediculosis Capitis
MC in children, scalp usually pruritic
Diagnosis straightforward.
Peripilar hair casts easily
differentiated b/c moveable, but
trichorrhexis nodosum mimics nits
Tx: Apply Permethrin 1% Cream
Rinse (Nix) to DRY hair, then rinse
out after 30-60 minutes. Do not
shampoo for 24 hours afterwards.
Pediculosis Capitis
Pediculosis Corporis
Aka: Pediculosis Vestimenti or Vagabond’s
Dz. Likes pressure areas beneath collar,
belt or in bedding.
LICE RARELY FOUND ON SKIN.
Dx: Generalized itching, parallel scratch
marks, hyperpigmentation, LSC & red
macules
Tx: Laundering clothing and bedding, 1%
Malathion powder, 10% DDT may be dusted
onto inner surface of underwear
Best to discard clothing altogether as lice
may live in clothing for 1 month without a
blood meal
Pediculosis Pubis (Crabs)
MC Adults, STD, MC genitalia but may
invade hypogastrium, axilla or eyelashes.
LICE COMMONLY FOUND ON SKIN
Pthirus pubis
Maculae ceruleae, bluish or slate colored
papules, blancheable on sides of trunk or
inner thighs.
Tx: Permethrin x 10 minutes, Repeat in 1
week, Tx Partner as well. Petrolatum for
eyelash lice.
Order Diptera – Dz Associations
Muscidae – tsetse fly,
(trypanosomiasis), (myiasis)
Simulidae – black fly (onchocerciasis)
Psychodidae ,Phlebotomus, sandfly,
(leishmaniasis, verruga peruana)
Culicidae (mosquitoes), filariasis,
malaria, dengue, yellow fever, WNV.
Diptera – 3 main problems
Mosquito bites
Ked itch
Myiasis
Mosquito bites – Culicinae
Moisture, warmth, carbon dioxide,
estrogens and lactic acid in sweat attract
the mosquito
Pruritic wheal, urticarial reactions.
West Nile Virus vector, mosquitoes
acquire it from feeding on infected birds.
Avoid standing water, wear long sleeves.
TX: topical steroids, DEET.
Also vectors for filariasis, malaria,
dengue, yellow fever.
Ked itch
Sheep ked = Melophagus ovinus
Yet another bloodsucker.
Woolsorters and sheepherder’s
Pruritic often hemorrhagic papules,
nearly always with a central punctum
Deer keds attack people in a similar
way, MC hips and abdomen, last 12m
Myiasis
Invasion of tissues by fly larvae, eggs
hatch, burrow into skin. Wounds MC.
Furuncle with maggots in the center.
Cochliomyia hominivorax (Screw worm)
MC cause wound myiasis in USA
Phormia regina (Black Blowfly, USA)
Dermatobia hominis (botfly, New World)
Cordylobia anthropophaga (Tumbu Fly,
Africa)
TX: EXCISION OR
OCCLUSION W/
PETROLATUM
Blister Beetle Dermatitis
Meloidae, Oedemeridae release the
vesicating agent cantharidin
Staphylinidae releases pederin
Not biters, vesicant rubs off if beetles
brushed against, pressed or crushed on
the skin
Linear array of vesicle(s), bulla(e)
“Spanish Fly” or Lytta vesicatoria best
known for medicinal purposes
TX: I&D, Cold compresses, Top CS.
Spanish Fly – Rick Lin’s special
formula extracted during mating
Carpet Beetle Dermatitis
Anthrenus scrophulariae
Papulovesicular and urticarial
involves chest, neck and forearms.
Reddish brown, fusiform 6mm long
and covered by hairs
TX: Fumigate house with sulfuryl
fluoride
Carpet beetle – note hairs
Anthrenus scrophulariae
Bees and Wasps
Bees or APIDS – venom contains
histamine, mellitin, hyaluronidase, HMW
acid phosphatase, phospholipase A
Wasps or VESPIDS – venom contains
phospholipase, hyaluronidase and a
protein known as ANTIGEN 5.
Honeybee stinger stays in the skin and has
a sac you must scrape off, because if you
pick it up by the sac, you express more
venom into the tissues.
Bee and Wasp Stings
Symptoms vary from a small pruritic wheal
to anaphylactic shock.
Bee sting anaphylaxis may be first
symptom of mastocytosis.
Treatment with IL steroids and xylocaine is
highly effective.
ASA or meat tenderizer compresses.
Anaphylaxis 0.3cc epi 1:1,000 SQ
Susceptible persons should carry an
Ana-Kit with syringe, epinephrine and
Antihistamines
Yellow jacket – MCC of allergic
reaction to insect stings
Nest in the ground or in walls, interrupted by outdoor activity
Ants – Fireants most painful
Solenopsis saevissima, invicta, geminata,
xyloni
S. saevissima is ferocious and vicious:
multiple bites in seconds.
Intense pain, whealing and eventually
sterile pustule with erythematous base,
very characteristic lesion.
Seizures and mononeuropathy have been
reported.
Tx: IL steroids  oral steroids, SQ epi
“Hasta la vista, baby”. -- Arnold
Schwartzenegger, Terminator
Solenopsis saevissima
Pulicosis (Flea Bites)
Human – Pulex iritans
Cat – Ctenocephalides felis
Dog – Ctenocephalides canis
Extraordinary jumpers, no wings
Legs and waist MC sites
Hemorrhagic puncta surrounded by
urticarial patch. “zigzag lines” or grouped
Well’s syndrome may occur (eosinophilic
cellulitis
Pulex iritans (Human flea)
below….
Ctenocephalides felis
Cat flea on the right 
Fleas as Vectors of Disease
Xenopsylla cheopis and X. brazilensis
are vectors of plague and endemic
typhus
Squirrel flea, Diamanus montanus
transmits plague and tularemia
Flea Control
Malathion, Chlordane in kerosene,
Lindane dusts or sprays, again, may
be easiest to call the Orkin man.
Insect repellants OFF!, other DEET
and pyrethrum preparations.
Tungiasis
Tunga penetrans
Aka nigua, chigoe, sand flea, jigger.
Reddish brown flea 1mm long
Africa, Central & S. America, India,
Pakistan
Pregnant females burrow into skin of
ankles, soles, feet and toes.
Lesions become infected and painful
Tunga penetrans
Aaahhh-nold
TX: Sx, Abx,
Thiabendazole
Tick Bites & Disease Associations
Dermacentor andersoni – wood tick (USA)
& Amblyomma americanum – Lone Star
tick (Texas) both transmit Rocky Mountain
Spotted Fever, Tularemia & tickborne
encephalitis
Ixodes transmit Lyme dz in USA
Dermacentor variabilis (dog)  Tularemia
Rhipephalus sanguineus (dog) 
Rickettsia conorii (Boutonneuse fever)
Ticks also transmit Q fever, Babesiosis,
Ehrlichosis, Arbovirus, Viral encephalitis,
Hemorrhagic fevers.
Tick Bite Presentations
1) Urticarial wheal
2) Tick Bite Pyrexia – 7-12 days of fever,
chills, headache, abdom. pain & N/V.
3) “Tick Paralysis” – usually in children, 6
days after attachment, rare, MC head/neck.
Flaccid paralysis of legs, then arms, neck,
diaphragm, resembles Guillen-Barre
syndrome. Tick toxins block NMJ’s.
Tick removal causes rapid recovery, but
death may ensue if tick is not removed.
Other Tick Bite Diagnosis
Ornithodorus tholozani may be a
vector for Borrelia duttonii, African
endemic relapsing fever
Bite produces typical small
inflammatory nodule surrounded by a
zone of normal skin with a
circumferential brownish ring.
Scabies
Distribution:
Circle of Hebra
Imaginary circle
intersecting sites
of prediliction –
areolae, axillae,
elbow flexures,
wrists, finger
webs, umbilicus,
lower abdomen,
genitalia
Scabies
Papular and burrow-type lesions
Face and scalp spared in adults, but not in
infants or immunosuppressed.
Burrows may be barely visible
Dull red nodules persist in groin, called
nodular scabies, may persist after cure,
histo = pseudolymphoma
Norwegian – heavy crusting, scaling most
common in malnourished, immunosuppressed or pts with neurologic dz.
Sarcoptes scabiei
Mineral oil or AcryMount on a glass slide
with cover slip on top
Scybala
Scabies Treatment
Norwegian: Ivermectin 200mg/kg weekly x
3.
Permethrin 5% cream from head to toe at
night, rinse off in AM x 3. May repeat
weekly.
Lindane rarely neurotoxic to infants
Infants and Pregnant women 6-10%
precipitated sulfur in petrolatum applied
nightly x 3 nights
Treat family members
Animal Scabies
Milder course than human scabies
Dogs, cats, poultry, birds, camels or
horses
Self limited, no burrows or mites
found.
Cheyletiella Dermtitis
Non burrowing mites that are parasitic
on dogs, cats, rabbits
May bite humans leaving itchy
dermatitis resembling scabies
Mites easily seen on pets.
Treatment of pet by veterinarian is the
only necessary treatment
Demodex mites - Demodicidosis
MC adults > 30 yo inhabit sebaceous
glands of the nose, ala, forehead,
chin and scalp
Significant only if in large numbers.
Readily found in adults without
disease – pathogenicity controversial
Occasionally, recalcitrant rosacea
patients may benefit from permethrin
Papulonodular AIDS eruptions
Demodex folliculorum – found in
contents expressed from seb gland
Chigger Bite
Eutrombicula alfreddugesi
MC legs and belt line and other sites
where clothing causes constriction
Grass and bushes typically infested in
summer or fall  aka Mower’s mites
Pruritic hemorrhagic puncta surrounded
by red swellings
TX: TS, Prophylaxis: (DMP)
demethylphthalate solution
Gamasoidosis
Persons who handle canaries,
pigeons and poultry
MC arms & hands, papular, urticarial
Diagnosis of urticaria is usually made
Ornithonyssus and Dermanyssus
mites infest feathers, bite humans
Take about 1 week longer to resolve
than most bug bites, Tx: malathion
Grocer’s Itch
Pruritic dermatitis of forearms
Carpoglyphus passularum – dates,
prunes, figs.
Acarus siro and Tyrophagus longior –
handling cheese
Grain Itch
Pyemotes tritici
Lives in grain, attacks harvesters of
wheat, hay, barley, oats and other
cereals or other farmhands who work
around straw.
Urticaria papule with vesicle
hemorrhagic punctum
TX: malathion
Mite may not be demonstrable in skin.
Scorpion Sting
Hide during daytime in closets, shoes,
folded blankets, children’s sandboxes.
Any sting by a large scorpion should
be considered dangerous because
venom is hemolytic and neurotoxic
MC USA is Centruroides sculpturatus
Numbness, laryngeal edema, profuse
sweating & salivation, cyanosis,
nausea and paresthesia of the tongue
Tx: tourniquet, antivenin,
phentolamine, atropine, barbituates
MC USA: Centruroides sculpturatus
Latrodectism – Black Widow
Dark dry places under rocks, in
cellars, in wood piles.
Severe pain in minutes, spreads from
bite site to extremities and trunk,
severe GI distress, abdominal rigidity
delirium, paralysis. S/S last 2 days.
Abdominal pain so severe it may be
mistaken for appendicitis, colic or
food poisoning. Children may die.
Opiods, benzodiazepines, antivenin.
Lactrodectus mactans
13mm long, coal black with an
orange red hourglass on abdomen
Loxoscelism – Brown Recluse
2 types of reactions
Localized – Necrotic Cutaneous
- extensive gangrene, severe
edematous painful reaction within the
first 8 hours. Starts as bulla with
surrounding erythema and ischemia.
In one week central dark gangrenous
portion may become many cm wide
and lasting months before healing.
Diffuse – Viscerocutaneous - rare
Loxoscelism Therapy
1) Rest, Ice, Compression, Elevation
2) No hot packs or surgery
3) Dapsone 100mg BID
4) Aspirin
5) Surgery, if any should be delayed
4 to 6 weeks.
6) No benefit to surgical excision,
actually increases complications.
Sting Ray Injury
Unwitting victim steps on partially
buried stingray
Puncture wound that ulcerates.
Immediate sharp shooting pain with
edema and cyanosis, symptoms of
shock may occur
TX: Venom is detoxified by heat, so
soak affected foot in hot water x 1 hr.
Demerol for pain.
Snake Bite
Rattlesnake, Cottonmouth,
Copperhead
Venom = hydrolases, 30 enzymes,
anticoagulant, hemolytic, increased
capillary permeability
If treatment center cannot be reached
within 1 hour, tourniquet, incision and
suction in first 15 to 30 minutes,
antivenin, antibiotics, tetanus toxoid,
possibly surgical intervention
UR: Mocassin
LR: Copperhead
LL: Rattlesnake
Lizard Bite
Heloderma suspectum AZ, NM
Paralysis, Dyspnea, Convulsions
Death is rare, Tx= snakebite tx
The End….a special thanks to my
enthusiastic and attentive audience