Parasitic Skin diseases, Arthropod Flashcards
Leishmaniasis Gen/Def: Cutaneous, Mucocutaneous, visceral
Flagellated, OBLIGATE, AMASTIGOTE
Transmitted: phlebotomus sand flies
-Visceral leishmaniasis: Causes FEVER, HEPATOSPLENOMEGLY, THROMBOCYTOPENIA,
Leishmaniasis Epidemiology
- Reservoir: man, dog, rodents
- Usually NEW HOST (people who haven’t lived in area are the ones who get affected)
- Transmitted by sand fly taking blood meal→ inject stages into blood stream→ concentrate in skin (cool areas of body)
- Promastigote in blood stream
- AMASTIGOTE IN SKIN
Leishmaniasis Diagnosis
- Ulcer at site of bite
- seen in macs on histo in skin ulcers
- AMASTIGOTE in giemsan-stained tissue
- Cutaneous and mucoid forms: No antibodies, so use PCR
- Visceral:systemic, so use serology
Leishmaniasis Treatment
Prevention: cover up skin with clothing
Larval Migrans: Hookworms (ancylostomas) General/Def
Lack enzymes to penetrate basement membrane of skin
Larval Migrans: Hookworms (ancylostomas) Epidemiology
Definitive host: Dogs and Cats
-human is dead-in host
Larval Migrans: Hookworms (ancylostomas) Clinical features/ transmission
INTENSLEY prurtic, last for months, serpiginous eruptions on feet, buttocks, abdomen
- penetrates skin on contact
- Tropical areas, travelers, walking barefoot on sand a dog pooped in
Larval Migrans: Hookworms (ancylostomas) Diagnosis
-Visualizations, No Serology
Larval Migrans: Hookworms (ancylostomas) treatment/prevention
Keep sandboxes covered, wear shoes
Cercarial Dermatitis: Schistosomes General/Def
Aka:Swimmers itch, caused by NON-HUMAN trematodes(flukes)
Cercarial Dermatitis: Schistosomes Epidemiology
BIRDS (ducks) are definitive host, humans are dead-end host.
-Contracted by swimming in contaminated water
Cercarial Dermatitis: Schistosomes Clinical
Red itchy looking sores on skin-can’t fully penetrate skin-so die–causes inflammatory reaction
Cercarial Dermatitis: Schistosomes Diagnosis
Clinical findings
Cercarial Dermatitis: Schistosomes Treatment
Aleviate itching: Cold compress, basking soda, topical corticosteroids
Pediculosis (lice) General/Def
- infestation of lice
- pediculosis capitis: “head lice”
- Classification:
- Pediculosis capitis: head lice
- Pediculosis corporis (Body lice): pediculosis vestimenti, Vagabond’s disease (thickening of skin from persistent infestation),
- Pediculosis pubis : crabs
Pediculosis Epidemiology
- more common in girls: prefer long, clean hair
- common in Brazil, S. America, Central America (no one even seaks medical attention here
- can happen in every socioeconomic group. UNRELATED to hygiene (head lice), body lice IS related to hygiene
- spread by close contact, shared combs, brushes, towels, etc.
Pediculosis Diagnosis
- most characteristic symptom: pruritis on head which intensifies 3-4 wks
- itching, excessive scratching can cause sores→ which can then be infected
- VECTOR: typhus, trench fever (Body lice- not head lice)
- Viewing of Nits=Lice eggs
Pediculosis Treatment
- number of cases has increased
- no one product can 100% eradicate after single tx
- Chemical tx, natural products, combs, shaving, hot air, silicone-based lotions
- QUELL shampoo, short haircut
Scabies General/Def
- contagious skin infection that occurs in humans and animals
- mite (Sarcoptes scabiei) BURROWS under skin (pencil marks), causing intense itching
- “Seven year itch”
- Mange in dogs/cats
- Nit: eggs, attached to hair
- Nymph: small adult
- Adult: look like tiny crabs
- Survive only a few days at room temp
Scabies Epidemiology
- all ages, races, socioeconomic classes, Hygiene is IRRELEVANT
- most often in crowded, unhygienic areas
- ancient disease
Scabies Diagnosis
-Definitive dx: finding scabies mites or their eggs and fecal pellets (biopsy, or dermoscopy)
Scabies Treatment
- Tx similar to lice (shave and meds below)
- Be clean
Scabies Clinical Manifestations
- Classic Scabies (immunocompetent): Itching, inflammation, weeping/crusty patches, WEB OF Fingers most common site of infection.
- Crusted (Norwegian) Scabies (immunocompromised): Scaly rash, thick crust, highly infectious, death from 2ndary bacterial infection,
- Atypical scabies (rare): Face, palms, scalp, soles of feet.
Scabies Incubation period
Initial: 3-6 w
Re-infesteation: 3d
Tungiasis (fleas) General/Def
- inflammatory skin disease caused by Tunga penetrans flea
- “sand flea”, “chigger”
- bury in skin→swell (see black hole, then subcutaneous mass)
Tungiasis (fleas) Epidemiology
- found in tropics, but has spread all across world
- Lives in sand
Tungiasis (fleas) Symptoms
Painless at first–itching develops–lesions–multiple lesions can make it hard to walk
Tungiasis (fleas) treatment
Not covered
Tungiasis (fleas) diagnosis
Identification of fleas/eggs
Human Cutaneous Myiasis (Bot Fly) Epidemiolgy
- Tropics/subtropics of Africa/Americas
- Flies deposit eggs on skin, wounds, or dead tissue–hatch–larvae cut into skin
- Involves a VECTOR (mosquito)- Flies deposit eggs on mosquito–develop within mosquito–mosquito takes blood meal from human
Human Cutaneous Myiasis (Bot Fly) Clinical Presentation
Painful boil-like lesions, odorous (sometimes)
Human Cutaneous Myiasis (Bot Fly) Treatment
-Self limited, manual removal of larva (like squeezing a pimple)
