Ectoparasites Flashcards
Biting insect saliva
Contains 20 proteins
- vasodilators
- anti clotting agents
- anti platelet agents
- anti microbials
- enz for sugar breakdown
Induce inflammatin by release of his by mast cells
Lesions/scratching can lead to secondary bac infection
Arthropod hair & feces can lead to allergic rxns (Type I hypersensitivity)
Mast cells
His release
increased endothelium perm
post capillary venule dilation
increased inflammation
nerve ending irritation
wheal & flare rxn
Lesions
pruritus- itching
erythema- redness of skin due to cap congestion
macule- flat, discolored surface of skin
welt/wheal- A of edema on body surface, often w/ severe itching
papule- small circumscribed, solid elevated lesion
nodule- small, circumscribed, solid, elevated lesion of skin deeper than papule
necrosis- dead skin
eschar- black, scab like protective layer
Lice/ pediculus humanus capitis
cause pruritus & skin irritation
direct life cycle
person to person or shared objects
Insect or eggs
1% lindane; pyrethrins & piperonyl butoxide mousse, 0.5% malathion lotion
Body lice/ peduculus humanus humanus
cooties, graybacks, mech dandfruff
pruritis
direct life cycle
on body during meals
person to person or shared clothes
insects or eggs
Lindane; pyrethrins & piperonyl butoxide mousse; 0.5% malathion lotion, regular laundry with hot water
Pubic lice/ pthirus pubis
Crab lice
intense pruritis
direct life cycle
sexually transmitted
insect or eggs
lindane; pyrethrins & piperonyl butoxide; 0.5% malathion lotion
Human flea/pulex irritans
pruritis & erythema
direct life cycle
Insect demonstration
Antipruritics & antihistamines
Scabies/ sarcoptes scabiei
Scabies
intense pruritus in interdigital folds & sides of ingers, popliteal folds, wrists, inguinal regions, buttocks, elbows & external genitalia
Direct life cycle
Transmission by person to person or things
Char lesions & mites in skin scrapings
Lindane; 5% permethrin cream
Human follicule mites/ Demodex spp.
acne, blackheads, blepharitis & truncal rashes
Papular folliculitis in people with immundef
D. folliculorum & D. brevis
Direct life cycle
Direct contact
Show mite from infested follicule
Lindane treatment
Chigger mites/ Eutrombicula spp. / Trombicula automnalis
Larvae intense pruritis & dermatisis w/ erythematous marks progressing to papules & nodules @ wrists, angles, armpits, groin & waistline
Direct life cycle
Grass & bushes
Demonstrate mite
Treat w/ antipruritics & antihist
Ticks
Minor erythematious papules but some can cause paralysis from toxin release found in tick saliva (D. andersoni, D. variablilis & A. americanus)
More often when tick attaches in opposition to CNS
Direct & indirect
Transmitted from grass/bushes
Demonstrate tick or ticket bite
Mechanical removal of tick!
Bed bugs/ Cimex lectularius
Small red lesions, pruritus, sleplessness, anemia
Direct life cycle
Nocturnal- hid out during the day & feed at night
Furniture, bedding etc.
Pattern & location of bites, demonstrate insect
Treat w/ antipruritics & antihis
Human bofly
Myiasis
parasitic maggots living in human tissues following deposition of eggs onto skin
Painful lesion @ site of entry
- insect leaves lesion upon pupation
- if larva dies prior to pupation, an abcess forms
Dermatobia hominis cause Torsalo
Blister Beetle
secrete cantharidin which causes skin irritation, thingling & burning
Progress to vesicular dermatitis w/ pruritus & oozing
Give palliative
Arachnids
Loxosceles reclusa
Cause loxoscelism
- intense local pain & small blister
- tissue damage due to venoum injected
- necrosis
- eschar formation
- rare systemic rxn
Give palliative
Arachnids
Black widow/ Latrodectus spp.
Latrodectism
- general pain
- nausea
- vomiting
- faintness
- severity correlated w/ venom injected
- painful abdom & leg cramps, profuse sweating, lacrymation& spasm of jaw
Give antivenom
Arachnids
Centrutroides spp. & Tityus spp.- dangerous scorpions
Depends on age of scorpion, amt of venom injected etc.
Radiating, burnign pain, hymollytic toxin so necrosis, chills, death etc.
Diagnose by signs & symptoms
Give antivenom w/in 1st hr
Swimmer’s itch/ Schistosomes
cause cercarial dermatisis & severe pruritus
Due to Trichobilharzia sp.
Ornithobilharzia sp.
Gigantobilharzia sp.
Microbilharzia sp.
Heterobilharzia sp.
