Derm Mycoses/Parasitic (lec 23)

Question 1

Microsporum and trichophyton (dermatophytes) secrete what?

Answer 1

keratinase -> allows inhabit of keratinized tissue

Question 2

Dermatophyte classifications? (3)

Answer 2

1) zoophilic (animal to people)
2) antrophophilic (p-to-p)
3) geophilic (soil to people)

Question 3

Dermatophyte infestation presents as what on tissue exam?

Answer 3

hyphae and arthoconidia

Question 4

Dermatophyte cx?

Other tests?

Answer 4

DTM -> 3 days turns red

Fluorescence (microsporums)
KOH (arthroconidium)

Question 5

Tests for Trichophytin?

Answer 5

Galactomannan peptide

Crude antigen

Question 6

Dermatophyte infective stages?

Answer 6

Arthroconidia (primarily)

Micro/macroconidia

Question 7

Dermatophyte epidemiology?

Answer 7

moist skin

HIV, DM
Cushing’s
contact sports
communal baths

Question 8

Dermatophyte infection presentation?

Answer 8

red/inflamm edges w/ central clearing

hairloss w/ itching

Question 9

Dermatophytid is?

Answer 9

allergic rxn to fungal antigens away from site of infection (i.e. tinea pedis)

Question 10

Tinea capitis etiology?

Answer 10

M. canis
(P) zoonotic
(U) childhood

Question 11

Tinea capitis presentation?

Answer 11

Infects endo/ectothrix of hair/scalp

(P) black dot ringworm
alopecia from broken hair
scarring -> permanent hair loss

Question 12

Tinea pedis caused by? //

Answer 12

E. floccosum, T. mentgrophytes, T. rubum

Question 13

Tinea corporis/cruris caused by? //

Answer 13

M. canis, E. floccosum, T. mentgrophytes, T. rubum

Question 14

Tinea corporis/cruris epidemiology?

Answer 14

(U) men
DM, obese, ↑↑ sweat

transmission via towels, bedding, clothing

Question 15

Tiinea unguium is? //

Caused by?

Answer 15

onychomycosis

E. floccosum, T. mentgrophytes, T. rubum
(U) w/ candida

Question 16

Tinea versicolor caused by?

Answer 16

Malassezia furfur

Question 17

Malassezia furfur microbe characteristics?

Answer 17

Spaghetti/meatballs (hyphae & spherical cells)
Lipophilic
Yeast-like colonies

Question 18

Tinea versicolor epidemiology?

Answer 18

(C) tropics

(U) young adults

Question 19

Tinea versicolor presentation?

Diagnostics?

Tx?

Answer 19

macular patch of depigmented or hyperpigmented skin

KOH

Selenium sulfide, miconazole

Question 20

Tinea nigra caused by?

Answer 20

Hortaea werneckii

Question 21

Hortaea werneckii microbe characteristics?

Answer 21

Dimorphic yeast/mold

Halophile

Question 22

Tinea nigra presentation?

Epidemiology?

Diagnositcs?

Tx?

Answer 22

brown lesions

Tropical

KOH/microscopy

Iodine, azole creams

Question 23

Sarcoptes scabiei microbe characteristics?

Answer 23

Burrowing mite
Small, short legs
MOST SERIOUS

Question 24

Sarcoptes scabiei life cycle?

Answer 24

Female:
Fertilized on skin -> burrow -> eggs -> larva in 4 days -> adult in 2 wks

Male:
Shallow, surface burrows

Causes ↑↑ itching eruption, worse in p.m.

Question 25

Crusted Scabies presentation?

Answer 25

Incubation 1 mo Crusted, scaling, ↑↑ itchy lesions ↑↑ mites per lesion (C) HIV

Question 26

Pediatric Scabies presentation?

Answer 26

Similar to Crusted, | Lesions (P) blood-filled

Question 27

Scabies epidemiology? Diagnostics? Tx?

Answer 27

Direct P-to-P spread (P) zoonotic Crowded conditions Mineral oil -> scrape -> microscope 5% permethrin crm

Question 28

Phthirus pubis is? Spread? Diagnositics? Tx?

Answer 28

Lice in pubic hair Nits (eggs) cemented to hair Bite/feed -> itching/irritation P-to-P or bedding ID by site permethrin

Question 29

Pediculosis is? Caused by?

Answer 29

Head lice Pediculus humanus

Question 30

Pediculus humanus lifecycle? Pathogenicity?

Answer 30

Nits cements to hair/fiber -> egg to egg cycle 3wks Bloodsucking irritation

Question 31

P. humanus is vector for what dz? What is Vagabond's Disease?

Answer 31

typhus long-term infestation -> dark, think skin