Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

msk-derm > Bugs, parasites, infections > Flashcards

Bugs, parasites, infections Flashcards

You may prefer our related Brainscape-certified flashcards:
Dermatology Board Prep flashcards
1
Q

What are possible reactions to arthropod bites?

A

excoriated pruritic papules, papular urticaria, pemphigoid vesicles and bullae, pseudolymphomatous nodules, anaphylaxis, secondary infections

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are some diseases transmitted by fleas?

A

Rickettsia typhi, yersinia pestis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are some diseases transmitted by ticks?

A

Lyme disease, rocky mountain spotted fever, ehrlichiosis, anaplasmosis, tularemia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the typical presentation of bedbug bites?

A

Erythematous pruritic nodules that often appear overnight in a linear or grouped arrangement (breakfast, lunch, and dinner bites)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Where are bedbugs found?

A

Crevices of floors and walls, beddings, furniture (can survive for a long time without feeding)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the vector for lyme disease?

A

Ixodes scapularis (deer tick)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are the three stages of lyme borreliosis?

A

Stage 1: localized

Stage 2: disseminated

Stage 3: persistent infection (months or years later)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the classic presentation of lyme disease?

A

Erythema migrans with an initial erythematous macule/papule that enlarges within days to form an expanding annular lesion with a distinct red border and partially clearing center (bull’s eye)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What organism causes scabies?

A

The mite sarcoptes scabiei

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How are scabies transmitted?

A

Skin to skin contact with another person with the parasitic infection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the life cycle of the organism that causes scabies?

A

The female scabies mite burrows into the top layers of skin where she lays up to 3 eggs per day for one to two months

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the clinical presentation of scabies in immunocompetent patients?

A

Pruritic papules, usually somewhat scaly or crusted, preferentially distributed in “warm” areas of the body (axillae, groin, ankles, etc)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the clinical presentation of scabies in immunocompromised patients?

A

“crusted” or norwegian scabies with thick scaly plaques over most of the body

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How is scabies diagnosed?

A

“scabies prep” - microscopic examination of skin scrapings that can reveal mites, eggs, or scybala (mite feces)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are different causes of pediculosis?

A

Pediculus humanis var. capitus (head), pediculus humanis var. humanus (body), pthirius pubis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the transmission of pediculosis?

A

Direct contact between individuals or indirect contact with bedding, brushes, or clothing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

How is head lice identified?

A

Nits or organisms in hair

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is the cause of tunga penetrans?

A

Sand flea infestation, classically along the toenail fold

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is the appearance of lesions in tunga penetrans?

A

Papule or vesicle with central back dot (from the flea), can have intralesional hemorrhage, eggs/feces/flea organs are extruded when lesions are squeezed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What locations are most likely sites for tunga penetrans lesions?

A

Feet, especially under toenails, between toes, and plantar aspects of feet

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is the agent that causes cutaneous larva migrans?

A

Nematode parasites (a variety)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What are the clinical manifestations of cutaneous larva migrans?

A

Erythematous, serpiginous, papular, or vesicular linear lesions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is the clinical presentation of myiasis?

A

A domed nodule that has a central pore through which the posterior end of botfly larva protrudes to respire

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

A patient complains of itchy finger webs and on examination has scaling between the fingers, a few scaly papules on the wrists, and edematous pink papules and a few nodules on the scrotum. Next step:

a) recommend testing for STDs
b) skin scraping for KOH to evaluate for tinea manuum
c) skin scraping for scabies preparation
d) treatment for psoriasis

A

c) skin scraping for scabies preparation

scrotal nodules are scabies until proven otherwise

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

A patient was hiking in upstate New York 2 weeks ago and got many bug bites. One in the groin has not gone away but rather grown into a large annular plaque which she fears is ringworm. On examination she has a 7 cm pink annular nonscaly plaque in the inguinal area. She feels otherwise well. You suspect:

a) bedbug bites from her hotel
b) tinea cruris
c) erythema marginatum
d) erythema migrans

A

d) erythema migrans

classic presentation of lyme borreliosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

A patient presents with several linearly arranged pruritis edematous excoriated 5 mm papules on both of her legs. These seem to come in crops. It is winter and she has no known exposure to mosquitoes. Her husband may have had a few similar lesions. You recommend:

a) use of DEET when she goes outdoors
b) treatment for shingles
c) professional extermination
d) she should get a new mattress

A

c) professional extermination

classic description for bedbugs, which requires extermination

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What is your diagnosis?

a) tinea versicolor
b) tinea corporis
c) tinea capitis
d) scabies
e) herpesvirus infection

A

b) tinea corporis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What is the most likely diagnosis?

A

Tinea corporis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What is the appearance of tinea corporis on KOH prep?

A

Fungi with hyphae that have septations

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What is the most likely diagnosis?

A

Tinea corporis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What is the most likely diagnosis?

a) tinea versicolor
b) tinea corporis
c) tinea capitus
d) scabies
e) herpesvirus infection

A

c) tinea capitus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

What is the histological presentation of tinea capitus?

A

Spores within and along hair shaft

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

What is the leading diagnosis?

A

Tinea capitus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

What is the leading diagnosis?

a) tinea versicolor
b) tinea corporis
c) tinea capitus
d) scabies
e) herpesvirus infection

A

a) tinea versicolor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

What is the appearance of tinea versicolor on histology?

A

Spaghetti and meatballs (yeast)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

What is the most likely diagnosis?

A

Tinea versicolor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

What is the most likely diagnosis?

A

Herpesvirus infection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

What is the most likely diagnosis?

A

Scabies

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

What is the most likely diagnosis?

A

Scabies

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

What is the most likely etiology of scrotal nodules?

A

Scabies

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

What is the most likely diagnosis?

A

Scabies

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

What is the most likely diagnosis?

A

Norwegian scabies (scabies in immunocompromsied patients)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

What organism is this? What disease might it transmit?

A

Louse - epidemic typhus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

What disease might this transmit?

A

Lyme disease (deer tick)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

What is the most likely diagnosis?

A

Lyme disease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

What type of organism is this?

A

Bedbugs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

What is the most likely diagnosis?

A

Bedbugs (breakfast, lunch, and dinner bites)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

What is the most likely diagnosis?

A

Tunga penetrans/tungiasis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

What is the most likely diagnosis?

A

Myiasis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

What are the clinical presentations of tinea capitis?

A

Seborrheic (scaling with minimal inflammation), black dot (hair shaft is brittle and breaks at scalp), kerion (inflammatory, boggy plaque with broken hairs and oozing purulence)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

What is the appearance of tinea capitis on Wood’s lamp?

A

Green fluorescence in hair above level of scalp due to pteridines from infection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

What types of infections cause tinea capitis?

A

Dermatophyte infection (microsporum, trichophyton, epidermophyton species)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

How should tinea capitis be evaluated?

A

With a KOH prep of the hair and/or fungal culture

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

What is the treatment for tinea capitis?

A

Oral antimycotic agents and selenium sulfide or ketoconazole shampoo

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

What is the clinical presentation of tinea corporis?

A

Dermatophyte infections of glabrous skin, pruritic lesions with central clearing that resemble a ring (“ring worm”), centrifugal spread after 1-3 weeks incubation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
56
Q

What is the clinical presentation of tinea facei?

A

A form of tinea with facial involvement that excludes beard and moustache areas

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
57
Q

What is the treatment for tinea corporis, cruris, facei, manuum, and pedis?

A

Topical or systemic -azole treatments

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
58
Q

What is the most common cause of superficial and systemic candidiasis?

A

Candida albicans

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
59
Q

What is the structure of candida albicans?

A

Yeast with pseudohyphae in the cold, germ tube formation in the warm

60
Q

What is the clinical presentation of cutaneous candidiasis?

A

Erythematous, macerated areas of skin with satellite vesicopustules, which can break and leave scale

61
Q

What is congenital candidiasis?

A

Candidiasis that is acquired in utero and presents within the first 24 hours of life as erythema and vesiculopustules with desquamation

62
Q

What is neonatal candidiasis?

A

A form of candidiasis that is acquired at birth and develops several days after as erythema and satellite pustules that resemble intertriginous candidiasis

63
Q

What is the treatment for cutaneous candidiasis?

A

Topical nystatin (localized), amphotericin B (systemic)

64
Q

What is pityriasis versicolor?

A

A malassezia infection of the skin that causes fine, scaly/dustlike hypo-pigmented or salmon-colored patches on trunk and proximal extremities, more common in hot/humid weather

65
Q

What is the finding of pityriasis versicolor on KOH prep?

A

Spaghetti and meatballs

66
Q

Where are sporotrichosis infections most common?

A

Temperate and tropical countries, in US present in midwestern river valleys

67
Q

What is the appearance of a sporotrichosis infection?

A

Dermal nodule that breaks down into a small ulcer, draining lymphatics that are inflamed and swollen, soft secondary nodules along the course of lymphatics

68
Q

What is mycetoma?

A

A chronic localized infection caused by different species of fungi or actinomycetes, causes abscesses that can drain into sinuses or adjacent bones

69
Q

Where are mycetoma infections most common?

A

Dry tropics with low annual rainfall

70
Q

What is the clinical presentation of chromoblastomycosis?

A

Chronic fungal infection of the skin where pigmented fungi are implanted into the skin causing inflammation

71
Q

Where is chromoblastomycosis most commonly found?

A

Mostly in tropical regions throughout central and south america

72
Q

What are the main types of endemic respiratory mycoses?

A

Histoplasmosis, blastomycosis, coccidiodomycosis, paracoccidiodomycosis

73
Q

What is the clinical presentation of systemic blastomycosis infection?

A

Lungs, skin, bones, CNS

74
Q

What geographic regions have endemic blastomycosis?

A

North America (great lakes region and southern US) and Canada

75
Q

What is the presentation of a skin lesion from disseminated blastomycosis?

A

Papule or nodule that may ulcerate and discharge pus

76
Q

What is the presentation of blastomycosis on KOH prep?

A

Rounded, refractile spherical cells with broad-based buds

77
Q

What is the most common cause of superficial pyodermas?

A

Staphylococcus aureus, group B strep (in babies)

78
Q

What are superficial pyodermas?

A

Infections in the epidermis, just below the stratum corneum (impetigo) or hair follicles (foliculitis)

79
Q

What is the clinical presentation of nonbullous impetigo?

A

Lesions that arise on the skin of the face (nares) or extremities after trauma. Initial lesion is a transient vescile or pustule that evolves into a honey-colored crust.

80
Q

What is the clinical presentation of bullous impetigo?

A

A condition caused by staph aureus where exfoliative toxins cause blistering by binding to desmoglein-1, causing bullae with yellow fluid that rupture and form honey-colored crusts

81
Q

What is the treatment for impetigo?

A

Bacterial culture to determine sensitivity. Treat with mupirocin ointment and oral antibiotic (specifically penicillin if group A strep)

82
Q

What is folliculitis?

A

Multiple small papules and pustules on an erythematous base that are pierced by a central hair (although hair may not always be visible)

83
Q

What is a furuncle?

A

Larger boil-like lesion that contains pus

84
Q

What are common types of folliculitis?

A

Staph aureus (most common), gram negatives (enterobacter, klebsiella, escherichia, serratia, proteus), pseudomonal (hot tub folliculitis)

85
Q

What is the main cause of erythrasma?

A

Corynebacterium minutissimum

86
Q

What is erythrasma?

A

Chronic superficial infection of the intertriginous areas of skin with brownish/red patches with fine scales along skin folds

87
Q

What factors predispose people to erythrasma?

A

Excessive sweating, delicate cutaneous barrier, obesity, DM2, warm climate, poor hygiene, advanced age

88
Q

What is the treatment for erythrasma?

A

Topical erythromycin

89
Q

What are the main causes of cellulitis?

A

Staph aureus/group a strep, MRSA

90
Q

What is cellulitis?

A

Deep, local infection with red hot swollen tender skin

91
Q

What is the treatment for cellulitis?

A

Systemic antibiotics

92
Q

What is the cause of toxic shock syndrome?

A

TSST-1 superantigen from staph aureus

93
Q

What is the cause of scalded skin syndrome?

A

Exfoliatin toxins A & B from staph aureus phage group 2 types 71 and 55

94
Q

How do exotoxins from staph aureus cause scalded skin syndrome?

A

The toxins bind to desmoglein-1 in the granular cell layer

95
Q

Who is most likely to experience scalded skins yndrome?

A

Patients < 5 (due to decreased renal function)

96
Q

What is the appearance of scalded skin syndrome?

A

Faint orange-red scarlitiniform eruption that become large, flaccid bullae. Begins with tissue paper-like wrinkling of epidermis followed by flaccid bullae in the axillae/groin that spreads over the body. The epidermis is then shed.

97
Q

What is the treatment for scalded skin syndrome?

A

Antibiotics, supportive care, fluid/electrolyte management

98
Q

What is the cause of scarlet fever

A

Streptococcal pyogenic exotoxins (SPE-A,B,C) from group A streptococcus in pharyngeal infection

99
Q

What type of skin reaction is scarlet fever?

A

Delayed-type skin reactivity to strep products (requires prior exposure)

100
Q

What are the constititutional symptoms of scarlet fever?

A

Pharyngitis, fever, headache, and chills with a rash after 1-2 days

101
Q

What are the enanthematous symptoms of scarlet fever?

A

Beefy-red pharynx and tonsilitis with submandibular lymphadenopathy, strawberry tongue (white first, then red), petechiae of the soft palate

102
Q

What are the exanthematous symptoms of scarlet fever?

A

First appears on the head/neck, spreads to whole body (except palms and soles) within 1-2 days, diffuse erythema with sandpaper quality, circumoral pallor, marked rash in skin folds, linear petechia in antecubital and axillary folds

103
Q

What is the treatment for scarlet fever?

A

Penicillin

104
Q

What is the cause of antrhax?

A

Bacillus anthracis (large, box-car shaped, gram-positive, non-motile, spore-forming rod)

105
Q

What are the three presentations of anthrax?

A

Inhalational, GI, cutaneous

106
Q

What is the appearance of cutaneous anthrax?

A

Painless papule that develops a central vesicle, ulcers, and forms a black eschar that can progress to bacteremia and death

107
Q

What causes black eschar in anthrax?

A

Lethal factor and edema factor from bacillus anthracis

108
Q

What is the presentation of pulmonary anthrax?

A

Flulike symptoms that rapidly progress to fever, pulmonary hemorrhage, mediastinitis, and shock

109
Q

What is the cause of secondary syphilis?

A

Untreated infection with treponema pallidum

110
Q

What is the clinical progression of syphilis?

A

Primary lesion: chancre (ulcer with raised borders and erythematous base)

Secondary: wide-spread papulosquamous skin lesions with diffuse scaly papules that can look like psoriasis and classically involve palms and soles with associated lymphadenopathy, “moth eaten” alopecia, and mucous patches

111
Q

What is the immunopathogenesis of secondary syphilis?

A

T cell reaction in the lesions of secondary syphilis

112
Q

What is the test for syphilis?

A

Serum RPR with prozone, treponemal tests

113
Q

What is the treatment for syphilis?

A

Penicillin

114
Q

What are the two most frequent skin forms of tuberculosis?

A

Lupus vulgaris and scrofuloderma

115
Q

What is lupus vulgaris?

A

A progressive form of cutaneous tuberculosis with nodular skin lesions on the face

116
Q

What is scrofuloderma?

A

Subcutaneous tuberculosis that leads to cold abscess formation and a breakdown of overlying skin that can be multibacillary or paucibacillary

117
Q

What are the risk factors for mycobacterium marinum?

A

History of trauma and water, fish/seafood related hobbies and occupations

118
Q

What is the presentation of mycobacterium marinum?

A

Violaceous papule at the site of trauma 2-3 weeks after inoculation that can lead to a nodule or psoriasiform or verrucous plaque that may ulcerate

119
Q

What is leprosy?

A

A chronic granulomatous infection caused by mycobacterium leprae that primarily affects skin and nerves

120
Q

How can the diagnosis of dermatophyte infection be confirmed?

a) Tzanck smear
b) KOH prep
c) mineral oil prep
d) punch biopsy

A

b) KOH prep

121
Q

Whenever possible, bacterial infections should have what test performed in order to confirm the diagnosis and guide management?

a) gram stain
b) bacterial culture
c) bacterial culture and sensitivity
d) KOH prep
e) Tzanck smear

A

c) bacterial culture and sensitivity

122
Q

What is the most likely diagnosis?

A

Tinea pedis

123
Q

What is the most likely diagnosis?

A

Onychomycosis

124
Q

What is the most likely diagnosis?

A

Tinea corporis

125
Q

What is the most likely diagnosis?

A

Tinea versicolor

126
Q

What is the most likely diagnosis?

A

Candidal intertrigo

127
Q

What is the most likely diagnosis?

A

Sporotrichosis

128
Q

What is the most likely diagnosis?

A

Blastomycosis

129
Q

What is the most likely diagnosis?

A

Bullous impetigo

130
Q

What is the most likely diagnosis?

A

Non-bullous impetigo

131
Q

What is the most likely diagnosis?

A

Staphylococcal scalded skin syndrome

132
Q

What is the most likely diagnosis?

A

Scarlet fever

133
Q

What is the most likely diagnosis?

A

Cellulitis

134
Q

What is the most likely definition?

A

Erysipelas

135
Q

What is the most likely diagnosis?

A

Abscess

136
Q

What is the most likely diagnosis?

A

Folliculitis

137
Q

What is the msot likely diagnosis?

A

Furunculosis

138
Q

What is the most likely diagnosis?

A

Carbunculosis

139
Q

What is the most likely diagnosis?

A

Cutaneous anthrax

140
Q

What is the most likely diagnosis (added HPI: lesions on palms and soles)?

A

Secondary syphilis

141
Q

What is the most likely diagnosis?

A

Lupus vulgaris

142
Q

What is the most likely diagnosis?

A

Scrofuloderma

143
Q

What is the most likely cause of this lesion on a pet shop employee?

A

Mycobacterium marinum

144
Q

What is the most likley diagnosis?

A

Mycobacterium leprae

145
Q
A

msk-derm (41 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions