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USMLE Step 3 MTB > Dermatology > Flashcards

Flashcards in Dermatology Deck (134)
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1
Q
  • 30-40 yoa
  • AI disease of unclear etiology
  • Abs produced against Ags in intercellular spaces of epidermal cells
  • possible causes are idiopathic, ACEI, penicillamine
  • bullae are relatively thin and fragile
  • POSITIVE Nikolsky’s sign
  • PAINFUL
  • not pruritic
  • fluid loss and risk of infection d/t loss of skin integrity
  • life-threatening
  • mouth involvement
A

pemphigus vulgaris

2
Q

MOST ACCURATE test for pemphigus vulgaris

A

skin biopsy

3
Q

treatment for pemphigus vulgaris

A

steroids

4
Q

treatment for pemphigus vulgaris if steroids are ineffective

A
  • azathioprine
  • mycophenolate
  • cyclophosphamide
5
Q
  • 70-80 yoa
  • can be sulfa drug-induced
  • deep blisters
  • thicker bullae much less likely to rupture
  • oral lesions are RARE
A

bullous pemphigoid

6
Q

test for bullous pemphigoid

A

skin biopsy w/ immunofluorescent Abs

7
Q

treatment for bullous pemphigoid

A

steroids

8
Q

alternative treatment to steroids for bullous pemphigoid

A
  • tetracycline

- erythromycin w/ nicotinamide

9
Q
  • associated w/ other AI diseases
  • can be drug-induced by ACEIs or NSAIDs
  • very superficial
  • NO oral lesions
A

pemphigus foliaceus

10
Q

diagnosis for pemphigus foliaceus

A

skin biopsy

11
Q

treatment for pemphigus foliaceus

A

steroids

12
Q
  • d/o of porphyrin metabolism
  • photosensitivity reaction to abnormally high accumulation of porphyrins
  • NONHEALING blisters on sun-exposed parts of body
  • hyperpigmentation of skin
  • hypertrichosis of face
A

porphyria cutanea tarda

13
Q

are associated w/ porphyria cutanea tarda

A
  • alcoholism
  • liver disease
  • chronic hepatitis C
  • OCPs
  • hemochromatosis
  • DM
14
Q

test for porphyria cutanea tarda

A

urinary uroporphyrins

15
Q

treatment for porphyria cutanea tarda

A
  • stop drinking alcohol
  • stop all estrogen use
  • barrier sun protection
  • phlebotomy/deferoxamine
  • chloroquine (increases porphyrin excretion)
16
Q
  • hypersensitivity reaction, most often mediated by IgE and mast cell activation
  • evanescent wheals and hives (onset w/i 30 minutes, and lasts
A

urticaria

17
Q

MCC of urticaria

A
  • medications
  • insect bites
  • foods
  • emotions
  • latex
18
Q

chronic urticaria is associated w/

A
  • pressure on skin
  • cold
  • vibration
19
Q

treatment for severe, acute urticaria

A
  • H1 antihistamines

- steroids if life-threatening

20
Q

treatment for chronic urticaria

A

H2 antihistamines

21
Q

treatment for urticaria when trigger cannot be avoided

A

desensitization

22
Q
  • milder version of hypersensitivity reaction than urticaria
  • “typical” drug reaction
  • rash resembles MEASLES (hence the name)
  • can appear days after exposure, and even after medication has been stopped
  • lymphocyte mediated
A

morbilliform rash

23
Q

treatment for morbilliform rash

A

antihistamines

24
Q

erythema multiforme causes

A
  • penicillins
  • phenytoin
  • NSAIDs
  • sulfa drugs
  • HSV, or mycoplasma infection
25
Q
  • target-like lesions especially on PALMS and SOLES

- can be described as “iris-like”

A

erythema multiforme

26
Q

treatment for erythema multiforme

A

antihistamines and treat underlying infection

27
Q
  • hypersensitivity response to medications (penicillins, sulfa drugs, NSAIDs, phenytoin, phenobarbital)
  • involves
A

Stevens-Johnson syndrome (SJS)

28
Q

treatment for Stevens-Johnson syndrome (SJS)

A
  • should be managed in burn unit

- IVIG, cyclophosphamide, cyclosporine, or thalidomide

29
Q
  • most serious version of cutaneous hypersensitivity reaction
  • 30-100% BSA involvement
  • positive Nikolsky’s sign
  • drug-induced
A

toxic epidermal necrolysis

30
Q

MCC of death in toxic epidermal necrolysis

A

sepsis

31
Q

are prophylactic systemic antibiotics indicated in toxic epidermal necrolysis?

A

NO

32
Q

causes of death in Stevens-Johnson syndrome (SJS)

A

infection, dehydration, and malnutrition

33
Q

diagnosis of toxic epidermal necrolysis

A

skin biopsy

34
Q

what effect do steroids have in toxic epidermal necrolysis?

A

decrease chances of survival

35
Q
  • LOCALIZED allergic drug reaction w/ repeated drug exposure

- round, sharply demarcated lesions that leave a hyperpigmented spot at the site after they resolve

A

fixed drug reaction

36
Q

treatment for fixed drug reaction

A

topical steroids

37
Q
  • painful, red, raised nodules on anterior surface of LE’s
  • nodules are TTP
  • do not ulcerate
  • ast about 6 weeks
  • 2/2 recent infections or inflammatory conditions
A

erythema nodosum

38
Q

inflammatory conditions associated w/ erythema nodosum

A
  • pregnancy
  • recent Streptococcal infection
  • coccidioidomycosis
  • histoplasmosis
  • sarcoidosis
  • IBD
  • syphilis
  • hepatitis
  • enteric infections
39
Q

treatment for erythema nodosum

A
  • analgesics and NSAIDs

- treat underlying cause

40
Q

best INITIAL test for:

  • tinea pedis
  • tinea cruris
  • tinea corporis
  • tinea versicolor
  • tinea capitis
  • onychomycosis
A

KOH test of skin

41
Q

MOST ACCURATE test for:

  • tinea pedis
  • tinea cruris
  • tinea corporis
  • tinea versicolor
  • tinea capitis
  • onychomycosis
A

fungal culture

42
Q
  • superficial bacterial infection
  • described as “weeping,” “oozing,” “honey-colored,” or “draining”
  • occurs in warm, humid conditions
  • more often caused by Staphylococcus, but sometimes Streptococcus pyogenes
A

impetigo

43
Q

complication of impetigo

A

glomerulonephritis

44
Q

treatment for impetigo

A
  • topical mupirocin

- PO antistaphylococcal abx if topical isn’t enough (dicloxacillin, cephalexin, or cefadroxil (PO))

45
Q
  • involves both dermis and epidermis
  • MCC by group A Streptococcus (pyogenes)
  • fever, chills, bacteremia
  • bright red, angry, swollen appearance to face
A

erysipelas

46
Q

treatment for erysipelas

A
  • dicloxacillin, cephalexin, or cefadroxil (PO)

- oxacillin, nafcillin, cefazolin (IV)

47
Q

if a pt is allergic to PCN w/ reaction being a RASH ONLY, can cephalosporins be used?

A

YES

48
Q

if a pt is allergic to PCN w/ reaction being ANAPHYLAXIS, can cephalosporins be used?

A

NO

49
Q

treatment for erysipelas if culture confirms Streptococcus

A

PCN G, or ampicillin (IV)

50
Q
  • involves dermis, and subcutaneous tissue
  • caused by Staphylococcus, or Streptococcus
  • +/- fever, hypotension, signs of sepsis
A

cellulitis

51
Q

empiric treatment for cellulitis

A

oxacillin, nafcillin, cefazolin (IV)

52
Q

treatment for mild cellulitis w/ MRSA

A

TMP/SMX, doxycycline, or clindamycin

53
Q
  • extremely severe, life-threatening skin infection
  • starts as cellulitis that dissects into fascial planes
  • Streptococcus and Clostridium are MC organisms
  • increased risk with DM pts
A

necrotizing fasciitis

54
Q

necrotizing fasciitis presentation:

A
  • very high fever
  • portal of entry into skin
  • pain out of proportion to superficial appearance
  • bullae
  • palpable crepitus
55
Q

diagnostic tests for necrotizing fasciitis

A
  • CPK

- XR, CT, or MRI to show air in tissue, or necrosis

56
Q

best way to confirm diagnosis and mainstay treatment for necrotizing fasciitis

A

surgical debridement

57
Q

antibiotic treatment for necrotizing fasciitis

A
  • ampicillin/sulbactam
  • ticarcillin/clavulanate
  • piperacillin/tazobactam
58
Q

treatment for necrotizing fasciitis if there is definite diagnosis of group A Streptococcus (pyogenes)

A

clindamycin and PCN

59
Q

mortality rate of necrotizing fasciitis w/o adequate treatment

A

80%

60
Q

infection loculated under skin surrounding a nail

A

paronychia

61
Q

treatment for paronychia

A
  • small incision to drain
  • antistaphylococcal abx
    (dicloxacillin, cephalexin, or cefadroxil (PO))
62
Q

multiple, painful vesicles of genitals

A

herpes simplex

63
Q

best INITIAL test for genital herpes simplex

A

Tzanck smear

64
Q

MOST ACCURATE test for genital herpes simplex

A

viral culture

65
Q

treatment for genital herpes simplex

A

PO acyclovir, famciclovir, or valacyclovir

66
Q

when should you treat a child for chickenpox?

A

if immunocompromised

same meds: PO acyclovir, famciclovir, or valacyclovir

67
Q

complications of varicella

A
  • PNA
  • hepatitis
  • dissemination
68
Q

treatment for severe pain in elderly pts w/ dermatomal herpes zoster

A

steroids

69
Q

best efficacy for decreasing risk of postherpetic neuralgia in dermatomal herpes zoster

A

acyclovir

70
Q

nonimmune adults exposed to chickenpox should receive what?

A

varicella zoster immune globulin w/i 96 hours of exposure

71
Q
  • warts (condylomata acuminata) [heaped up, translucent, white or flesh-colored lesions on mucous surfaces]
A

human papillomavirus (HPV)

72
Q

treatment for human papillomavirus (HPV)

A
  • mechanical removal

- imiquimod

73
Q
  • ulceration w/ heaped-up indurated edges

- painLESS

A

primary syphilis

74
Q

best INITIAL test for primary syphilis

A

darkfield microscopy

75
Q

treatment for primary syphilis

A

IM PCN single dose

76
Q

treatment for primary syphilis if PCN allergic

A

PO doxycycline x 2 weeks

77
Q
  • generalized copper-colored, maculopapular rash especially on PALMS and SOLES
  • mucous patch
  • alopecia areata
  • condylomata lata
A

secondary syphilis

78
Q

diagnostic tests for secondary syphilis

A

VDRL, or RPR (nearly 100% sensitive)

79
Q

treatment for secondary syphilis

A

IM PCN single dose

80
Q

treatment for secondary syphilis if PCN allergic

A

PO doxycycline x 2 weeks

81
Q
  • skin infection involving web spaces of hands and feet
  • can also cause pruritic lesions around penis and breast
  • burrows and excoriations around small pruritic vesicles
  • often spares the head
A

scabies

82
Q

scabies is confirmed by

A

scraping out organism after mineral oil is applied to burrow

83
Q

best INITIAL treatment for scabies

A

permethrin

84
Q

treatment for Norwegian scabies (severe crusting)

A

PO ivermectin

85
Q
  • includes the head
  • easily transmitted
  • extremely high rate of transmission
  • sometimes rust colored from ingestion of blood
A

pediculosis (lice and crabs)

86
Q

diagnosis of pediculosis (lice and crabs)

A

can be seen attached to hair-bearing areas

87
Q

treatment for pediculosis (lice and crabs)

A

permethrin

88
Q
  • target lesion (> 85%) = rash must be erythematous w/ central clearing and be at least 5cm in diameter
  • usually occurs 7-10 days after tick bite
A

lyme disease

89
Q

treatment for lyme disease

A

doxycycline, amoxicillin, or cefuroxime (PO)

90
Q
  • caused by Staphylococcus attached to a foreign body (nasal packing, retained sutures, surgical material retained in the body)
  • fever > 102
  • SBP
A

toxic shock syndrome (TSS)

91
Q

treatment for toxic shock syndrome (TSS)

A
  • vigorous fluid resuscitation
  • vasopressors
  • antistaphylococcal abx
    (oxacillin, nafcillin, cefazolin (IV))
92
Q

treatment for toxic shock syndrome (TSS) if MRSA

A

vancomycin, or linezolid

93
Q
  • mediated by toxin from Staphylococcus
  • loss of superficial layers of epidermis
  • Nikolsky’s sign
  • presents w/ NORMAL BP
  • NO involvement of liver, kidney, BM, or CNS
A

Staphylococcal scalded skin syndrome (SSSS)

94
Q

treatment for Staphylococcal scalded skin syndrome (SSSS)

A

IV oxacillin, or nafcillin

95
Q
  • cutaneous infection acquired from contact w/ infected livestock
  • occupational hazard of wool sorters
  • can be used for bioterrorism
  • papule w/ central necrosis (eschar)
  • 20% fatality if untreated
A

anthrax

Bacillus anthracis

96
Q

how is the diagnosis of anthrax confirmed?

A

gram stain and culutre

97
Q

treatment for anthrax

A

ciprofloxacin, or doxycycline

98
Q

MOST ACCURATE test for melanoma

A

full thickness biopsy of lesion

99
Q

most important prognostic factor for melanoma

A

tumor thickness

100
Q

treatment for melanoma

A

excision

101
Q

reduces recurrence rates of melanoma

A

interferon

102
Q
  • BENIGN

- hyperpigmented lesions in elderly pts (“stuck on” appearance)

A

seborrheic keratosis

103
Q
  • PRECANCEROUS (increases risk of SCC)
  • occur on sun-exposed areas in older pts
  • can be TTP
A

actinic keratosis

104
Q

treatment for actinic keratosis

A
  • cryotherapy
  • topical 5-FU
  • imiquimod
  • topical retinoic acid
  • curettage
105
Q
  • sun-exposed areas in elderly pts
  • commonly on the lip
  • ULCERATION is common
  • metastasis is rare
A

squamous cell carcinoma

106
Q

diagnosis of squamous cell carcinoma

A

biopsy

107
Q

treatment for squamous cell carcinoma

A

surgical removal

108
Q
  • shiny, or “pearly” appearance

- accounts for 65-80% of skin cancer

A

basal cell carcinoma

109
Q

how is diagnosis of basal cell carcinoma confirmed?

A

shave or punch biopsy

110
Q

treatment for basal cell carcinoma

A

surgical removal (Mohs microsurgery)

111
Q
  • purplish lesions

- HIV-positive w/ CD4 count

A

kaposi’s sarcoma

112
Q

treatment for kaposi’s sarcoma

A
  • ART to raise CD4 count

- liposomal doxorubicin and vinblastine if HIV-negative

113
Q
  • silvery scales on EXTENSOR surfaces
  • nail pitting
  • Koebner phenomenon (lesions that develop at site of epidermal injury)
A

psoriasis

114
Q

treatment for psoriasis

A
  • emollients (moisturizer)

- salicylic acid

115
Q

treatment for xerosis/asteatotic dermatitis

A

humidifiers and emollients

116
Q
  • high IgE levels

- red, itchy plaques on FLEXOR surfaces

A

atopic dermatitis

117
Q

preventive treatment for atopic dermatitis

A

emollients

118
Q

treatment for active disease of atopic dermatitis

A
  • AVOID SCRATCHING
  • topical steroids
  • antihistamines
119
Q
  • oversecretion of sebaceous material
  • hypersensitivity reaction to superficial fungal organism (Pityrosporum ovale)
  • scaly, greasy, flaky skin found on red base of scalp, eyebrows, and nasolabial fold
A

seborrheic dermatitis

120
Q

treatment for seborrheic dermatitis

A
  • topical steroids
  • topical antifungal
  • zinc pyrithione
121
Q
  • hyperpigmentation built up from hemosiderin

- occurs over long period from VENOUS incompetence of LE’s

A

stasis dermatitis

122
Q

prevention of stasis dermatitis

A

elevation of LE’s

123
Q
  • hypersensitivity reaction to soaps, detergents, latex, sunscreen, or neomycin
  • jewelry is a common cause
  • can present as linear streaked vesicles (especially when caused by poison ivy)
A

contact dermatitis

124
Q

definitive testing for contact dermatitis

A

patch testing

125
Q

treatment for contact dermatitis

A
  • identifying causative agent

- antihistamines and topical steroids

126
Q
  • pruritic eruption that begins w/ “herald patch”
  • erythematous and salmon colored
  • mild and self-limited, resolves in 8 weeks
A

pityriasis rosea

127
Q
  • pustules and cysts occur and rupture
  • caused by Propionibacterium acnes
  • discharge is odorless
A

acne

128
Q

treatment for acne: mild disease

A
  • topical antibiotics: clindamycin, erythromycin, or sulfacetamide
  • topical retinoids
129
Q

treatment for acne: moderate disease

A

benzoyl peroxide and retinoids

130
Q

treatment for acne: severe cystic acne

A
  • PO antibiotics

- PO retinoic acid derivatives

131
Q

definition of stage 1 pressure ulcer

A

nonblanchable erythema of INTACT skin

132
Q

definition of stage 2 pressure ulcer

A

superficial ulcers causing PARTIAL thickness loss of epidermis, dermis, or both

133
Q

definition of stage 3 pressure ulcer

A

deeper ulcers causing FULL thickness loss w/ damage to subcutaneous tissue that may extend to, but NOT through, any underlying fascia

134
Q

definition of stage 4 pressure ulcer

A

VERY deep ulcers causing FULL thickness loss w/ EXTENSIVE tissue destruction that may damage adjacent muscle, bone, or supporting structures