5: Parasitic Infections of Skin - Bennett

Question 1

rocky mountain spotted fever transmitted by …

Answer 1

ixodid tick bite

Question 2

s/s rocky mountain spotted fever

Answer 2

• 3-14 days p tick bite
• HA, fever, chills, myalgias, arthralgia
• spotted rash day 1- day 6 appears beginning on *** wrists, forearms and ankles spreading to arms, thigh and trunk and finally face

Question 3

diagnosis rocky mountain spotted fever

Answer 3

immunofluorescent ab to anti-rickettsii ab

direct immunofluorescence of antigen w/i endothelial cells

Question 4

tx rocky mountain spotted fever

Answer 4

doxycycline 200 mg/day PO or IV in diviided doses

chloramphenicol 50-75 mg/kg/d in four divided doses

Question 5

ctenocephalides canis

Answer 5

dog flea

self-limiting

tx with topical antihistamine

Question 6

cimex lectularis

Answer 6

bed bug

Question 7

linear arrangement of papular urticaria

Answer 7

bed bug ( due to nocturnal feeding once a week)

tx with hydrocortisone or antihistamine

Question 8

pediculus humanus capitis

Answer 8

pediculosis (lice)

diagnose by discovery lice

tx with malathion in children

Question 9

pediculus humanus corporis

Answer 9

body louse

treat with good hygiene sometimes pyrethrin (kills lice and eggs) or malathion (kills lice and some eggs)

Question 10

areas affected by scabies in order of prevaence

Answer 10

- interdigital webs of hands
wrists
shaft of penis
antecubital crease
feet
genitalia
buttocks
axillae

Question 11

diagnosis scabies

Answer 11

finding burrow, drop mineral oil over burrow and scrape off to inspect

Question 12

tx scabies

Answer 12

permethrin (next choice lindane)

Question 13

most common cause cutaneous larva migrans in US

Answer 13

ancyclostoma brazilense (larvae of dog/cat hook worms)

Question 14

tx for cutaneous larval migrans

Answer 14

self-limiting but can use thiabendazole, ivermectin or albendazole topically if needed

Question 15

papulo-vesicular rash occurring only in regions covered by swimwear

Answer 15

seabather’s eruption

larvae of thimble jellyfish

lesions for about 2 wks, tx with topical steroid cream to reduce inflammation

Question 16

papule at site of sandfly bite

Answer 16

leishmaniasis

papules enlarge over several weeks and become dusky red purple color and eventually ulcerate and scar

diagnose by finding amastigotes and tx with pentostam

Question 17

tick for lyme disease

Answer 17

ixodid tick transmits borrelia burgdorferi

Question 18

stages and presentation of lyme disease (3)

Answer 18

I = erythema migrans : expanding annular lesion with distinct red broder and partially clearing center

2 = disseminated infection : fever, chills, myalgia, HA, weakness, photophobia, meningitis, carditis with heart block

3 = persisitent infection : fever, lymphadenopathy, arthritis, encephalopathy, polyneuropathy

Question 19

diagnose lyme disease

Answer 19

enzyme immunoassay of immunofluorescent assay followed by western immunoblot or cuture from skin biopsy

Question 20

tx lyme disease

Answer 20

doxycycline 100 mg BID for 10 d
20-30 d if stage 2
60 days in stage 3

Question 21

firm nodule, painful, maybe movement in tissue

Answer 21

bot fly! (uses intermediary host)