MTB 3 - Dermatology Flashcards

1
Q

How does pemphigus vulgaris present?

A

Painful bullae that are easily ruptured
Involvement of the mouth
Nikolsky’s sign

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2
Q

What’s the pathophysiology of pemphigus vulgaris?

A

IgG Antibodies against desmosomes.

Desmosomes allow cell-to-cell adhesion

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3
Q

What causes pemphigus vulgaris?

A

Idiopathic
ACE-I
Penicillamine

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4
Q

What 3 things can give Nikolsky’s sign?

A

Pemphigus vulgaris
SSSS
Toxic epidermal necrolysis

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5
Q

How to diagnose pemphigus vulgaris?

A

Biopsy of skin showing autoantibodies on immunofluorescent studies in a netlike pattern

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6
Q

Treatment of pemphigus vulgaris?

A

Prednisone
If inneffective, use azathioprine
Without treatment, this condition is fatal

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7
Q

Describe bullous pemphigoid:

A

Much milder disease than pemphigus vulgaris
Bullae stay intact so less fluid loss and infection
Mouth involvement is uncommon

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8
Q

Pathophysiology of bullous pemphigoid?

A

IgG antibodies against hemidesmosomes (basement membrane). Linear immunofluorescence.

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9
Q

How to diagnose bullous pemphigoid?

A

Skin biopsy showing linear immunofluorescence of IgG against the hemidesmosomes of the basement membrane

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10
Q

Treatment for bullous pemphigoid?

A

Prednisone

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11
Q

What ages does pemphigus vulgaris and bullous pemphigoid present?

A

Pemphigus vulgaris: 30’s and 40’s

  • Life-threatening
  • Thin and fragile bullae
  • Mouth involved
  • Nikolsky’s

Bullous pemphigoid: 70’s and 80’s

  • Thick and intact bullae
  • No mouth involvement
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12
Q

What is porphyria cutanea tarda (PCT)?

A

Disorder of porphyrin metabolism –>
High accumulation of porphyrins –>
Causes photosensitivity reaction

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13
Q

List 5 associations with PCT:

A
Alcoholism
Liver disease
 -Chronic Hep C
 -Hemochromatosis
OCP
Diabetes
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14
Q

How does PCT present?

A

Nonhealing blisters on sun-exposed part of body
Hyperpigmentation of skin
Hypertrichosis of face (excess hair)

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15
Q

How to test for PCT?

A

Urinary uroporphyrins will be 2-5x higher than coproporphyrins

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16
Q

How to manage PCT?

A

Stop alcohol
Stop estrogen use
Use sun protection
Phlebotomy to remove iron or deferoxamine
Chloroquine increases excretion of porphyrins

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17
Q

What is urticaria?

A

A localized, cutaneous anaphylaxis without hypotension or hemodynamic instability.
Caused by a hypersensitivity reaction by IgE and mast cell activation
Results in wheals and hives very pruritic

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18
Q

When is the onset of wheals and hives in urticaria? How long does it last?

A

Within 30 minutes of exposure. Lasts for

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19
Q

Most common medication causes of urticaria:

A
Aspirin
NSAIDs
Morphine
Codeine
Penicillin
Phenytoin 
Quinolones
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20
Q

Other common causes of urticaria besides medications:

A

Insect bites
Foods (peanuts, shellfish, tomatoes, strawberries)
Latex
Emotions (occasionally)

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21
Q

Chronic urticaria is associated with:

A

Pressure on skin
Cold
Vibration

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22
Q

How to treat urticaria?

A

Always: Antihistamines (diphenhydramine, hydroxyzine, cyproheptadine)

Life-threatening: Systemic steroids
Chronic therapy: Nonsedating antihistamines (loratadine, cetirizine)

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23
Q

When do you do desensitization for someone with urticaria?

A

When the trigger can’t be avoided (bee stings in a farmer).

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24
Q

What must you stop taking prior to desensitization?

A

Beta-blockers (cause you might need to use epinephrine which uses beta receptors)

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25
Q

What is a morbilliform rash?

A

Typical type of drug reaction to which the pt is allergic
Milder version of urticaria
Resembles measles
Generalized maculopapular eruption that blanches w/pressure

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26
Q

Treatment of morbilliform rash?

A

Antihistamines

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27
Q

How does erythema multiforme present?

A

Targetlike lesions on palms and soles

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28
Q

Erythema multiforme is caused by what things?

A
Penicillins
Phenytoin
NSAIDs
Sulfa drugs
HSV or mycoplasms infection
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29
Q

Treatment of erythema multiforme?

A

Antihistamines

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30
Q

Describe Stevens Johnson Syndrome:

A

Hypersensitivity reaction

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31
Q

Treatment of SJS?

A

IV immunoglobulin
Cyclophosphamide
Steroids don’t work

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32
Q

What things can cause SJS?

A

Penicillins
Phenytoin
NSAIDs
Sulfa drugs

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33
Q

Describe toxic epidermal necrolysis:

A
Most serious cutaneous hypersensitivity reaction
30-100% BSA
40-50% mortality
Nikoslky's sign
Sepsis most common cause of death
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34
Q

Should you give prophylactic antibiotics to pts with TEN?

A

No

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35
Q

How to diagnose TEN?

A

Skin biopsy

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36
Q

Treatment of TEN?

A

Doesn’t say

Don’t give steroids

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37
Q

What is a fixed drug reaction?

A

Localized allergic drug reaction at precisely the same location as drug exposure.

Round, sharply demarcated lesions that leave a hyperpigmented spot at site after they resolve

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38
Q

How to treat a fixed drug reaction?

A

Topical steroids

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39
Q

What does erythema nodosum look like?

A

Painful, red, raised nodules on shins

Nodules are tender, don’t ulcerate, and last 6 weeks

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40
Q

Name 9 conditions that cause erythema nodosum:

A
  1. Pregnancy
  2. Recent strep infection
  3. Coccidioidomycosis
  4. Hisoplasmosis
  5. Sarcoidosis
  6. IBD
  7. Syphilis
  8. Hepatitis
  9. Enteric infections (Yersinia)
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41
Q

Treatment of erythema nodosum?

A

Analgesics and NSAIDs

Treat underlying disease

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42
Q

Best initial test for cutaneous fungal infections:

A

KOH test of skin (dissolves everything but fungus)

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43
Q

Most accurate test for cutaneous fungal infections:

A

Culture the fungus

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44
Q

Treatment for oncyhomycosis (nails) or tinea capitis (hair)?

A

Oral terbinafine
Oral itraconazole
6 weeks for fingernails - 12 weeks for teonails

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45
Q

What is a problem with terbinafine and how do you watch out for it?

A

Hepatotoxicity

Check LFTs periodically

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46
Q

How does griseofulvin compare to terbinafine?

A

Not nearly as efficacious. Must use for 6-12 MONTHS

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47
Q

All other fungal infections that don’t involve hair or nails can be treated with topical medications. Name the meds:

A

Ketoconazole
Econazole
Clotrimazole
Miconazole

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48
Q

How does the efficacy of the topical antifungals compare?

A

No clear difference when used topically

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49
Q

If ketoconazole is given orally, what are some serious side-effects?

A

Hepatotoxicity and gynecomastia

-This is why it’s nto given for hair or nails

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50
Q

Describe impetigo:

A

Confined to epidermis
Weeping, oozing, honey-colored
Very contagious

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51
Q

What bugs cause impetigo?

A
Staph
Strep pyogenes (Group A)
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52
Q

Serious complication of impetigo?

A

Glomerulonephritis

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53
Q

Treatment of impetigo?

A

Topical mupirocen

If inneffective, use PO oxacillin/nafcillin

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54
Q

What layers does eryisepelas effect?

A

Epidermis and dermis

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55
Q

What bug causes erysepelas?

A

Strep pyogenes (group A)

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56
Q

Presentation of eryisepelas?

A

Fever, chills

Bright red, swollen appearance to the face

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57
Q

Treatment of erysipelas?

A

Systemic PO or IV:
Penicillin G or ampicillin if culture says it’s Strep

Otherwise:
Dicloxacilin
Cephalexin
Vanc if MRSA is suspected

58
Q

What layers does cellulitis effect?

A

Dermia and subcutaenous tissues

59
Q

Bugs causing cellulitis?

A

Staph

Strep

60
Q

What are folliculitis, furuncles, and carbuncles? What bug is responsible?

A

These are different degrees of severity of a staph infection around a hair follicle. Pseudomonas from hot tub can cause it, too.

Folliculitis

61
Q

Treatment of folliculitis?

A

Topical mupirocen

62
Q

Treatment of furuncles and carbuncles?

A

Drain carbuncles

Systemic dicloxacillin or cefadroxil for both

63
Q

Describe what necrotizing fasciitis is (not the sxs):

A

Extremely severe, life-threatening infection of skin

Begins as cellulitis and dissects into fascial planes of skin

64
Q

Symptoms of necrotizing fasciitis:

A
Very high fever
Pain out of proportion to appearance
Bullae
Palpable crepitus
Portal of entry in to skin
65
Q

What bugs cause necrotizing fasciitis?

A

Streptococcus

Clostridia

66
Q

What increases risk of necrotizing fasciitis?

A

DM

67
Q

How to diagnose necrotizing fasciitis?

A

Elevated CPK
X-ray, CT, or MRI showing air in tissue or necrosis
Surgical debridement (best way to confirm diagnosis)

68
Q

Treatment for necrotizing fasciitis?

A

Surgical debridement is mainstay
Zosyn

If there’s definite Strep pyogenes, tx is clindamycin and penicillin

69
Q

What is paronychia?

A

Infection in the skin surrounding a nail

70
Q

Treatment of paronychia?

A

Small incision for drainage +

Anti-staph drugs (nafcillin/oxacillin)

71
Q

HSV skin infection presentation:

A

Multiple, painful vesicles

72
Q

How to treat HSV infections?

A

ORAL Acyclovir, famciclovir, or valacyclovir if exam is obvious

Topical does nothing

73
Q

How to treat acyclovir-resistant herpes?

A

Foscarnet

74
Q

Best initial test for HSV?

A

Tzanck smear

75
Q

Most accurate test for HSV?

A

Viral culture (grows in 1-2 days)

76
Q

Complications of varicella in kids?

A

Pneumonia
Hepatitis
Dissemination

77
Q

Treatment of shingles?

A

Acyclovir to reduce risk of postherpetic pain
Steroids for elderly pts with severe pain

For postherpetic pain: Gabapentin

78
Q

How does HPV present?

A

White or flesh-colored, translucent heaped-up lesions

79
Q

Another term for HPV lesions?

A

Condylomata acuminata

80
Q

Diagnostic testing for Condylomata acuminata?

A

No form of testing is routinely necessary

81
Q

Treatment of Condylomata acuminata?

A
Take your pick from:
Cryotherapy w/liquid nitrogen
Laser
Trichloroacetic acid
Porodphyllin to melt them (avoid in pregnancy)
Imiquimod is local imunostimulant
82
Q

How does primary syphilis present:

A

Chancre = Ulceration with heaped-up indurated edges. Painless

83
Q

Best initial test for primary syphilis?

A

Darkfield exam (not VDRL/RPR due to 25% false neg rate)

84
Q

How to treat primary or secondary syphilis?

A

Single IM dose of penicillin

Doxycycline if allergic

85
Q

How does secondary syphilis present?

A

Generalized copper-colored, maculopapular rash, especially on palms and soles

86
Q

Best initial test for secondary syphilis?

A

VDRL and RPR (100% sensitivity)

87
Q

How does scabies present?

A

Very pruritic lesions in web spaces of hands and feet, penis, and breast.
May see burrows and excoriations around small vesicles

88
Q

Where does scabies spare?

A

Head

89
Q

How to test for scabies?

A

Scraping out organism after mineral oil is applied to a burrow

90
Q

Treatment of scabies?

A

Permethrin

91
Q

What is pediculosis?

A

Lice and crabs

92
Q

Where does pediculosis occur on the body?

A

Hairy places
Easily transmitted by hairbrushes and hats
Also through sexual contact (90% transmission from a single contact)

93
Q

How to diagnose pediculosis?

A

Viewing the organism on the hair under magnification

94
Q

Treatment of pediculosis?

A

Permethrin

95
Q

The rash of lyme disease occurs how long after the bite?

A

7-10 days

96
Q

What do you do if a rash looks erythematous with a central clearing and is at least 5cm in diameter?

A

It’s definitely Lyme disease, go directly to treatment

97
Q

How to treat Lyme disease?

A

PO Doxycycline or amoxicillin

98
Q

What will happen if you don’t treat lyme disease?

A

66% develop joint disease

Neurologic or cardiac disorders

99
Q

What causes toxic shock syndrome?

A

Staph infection from:

  • Nasal packing
  • Retained sutures
  • Tampons
100
Q

How to diagnose toxic shock syndrome?

A

Must have:

  • Fever >102
  • Systolic
101
Q

What can be found on labs with toxic shock syndrome?

A

High creatinine, CPK, LFTs
Low platelet count
CNS dysfunction (confusion)

102
Q

How to treat toxic shock syndrome?

A

Fluid resuscitation
Pressors (dopamine)
Oxacillin/nafcillin
Vanc or linezolid for MRSA

103
Q

How is SSSS different from TSS?

A

It has normal BP and doesn’t affect liver, CNS, etc

104
Q

Which layers of skin does SSSS affect?

A

Only the superficial granular layer

105
Q

Management of SSSS?

A

Admit to burn unit

Give oxacillin/nafcillin

106
Q

How is anthrax usually acquired?

A

From infected livestock

-Occupational hazard of wool sorters

107
Q

How does an anthrax infection present?

A

Cutaneous infection

-Inflamed papule that develops black central necrosis

108
Q

What does anthrax mean in Greek?

A

Coal

109
Q

Hwo to diagnose anthrax?

A

Gram stain and culture of lesion

110
Q

Treatment of anthrax?

A

Ciprofloxacin or doxycycline

111
Q

Describe melanoma

A
Malignant
Grow in size
Irregular borders
Uneven shape
Inconsistent coloring
112
Q

Most prognostic factor for skin cancer?

A

Tumor thickness

113
Q

Tx of melanoma?

A

Excision

114
Q

Describe seborrheic keratosis

A

Benign
Hyperpigmented lesions in elderly
Stuck-on appearance
Common on face, shoulders, chest, and back

115
Q

Treatment of seborrheic keratosis?

A

Liquid nitrogen OR curettage

This would only be done for cosmetic reasons as they are perfectly benign

116
Q

Describe actinic keratosis:

A

Precancerous
Sun-exposed area of body in older pts
May be tender

117
Q

Treatment of actinic keratosis?

A
Sunscreen to prevent progression/recurrenc
Removed with:
 -Cryotherapy
 -Topical 5FU
 -Imiquimod
118
Q

Describe squamous cell carcinoma

A

Sun-exposed skin surfaces in elderly
Common on lip (b/c of tobacco)
Ulceration
Metastases are rare (3-7% of pts)

119
Q

Desribe Basal cell carcinoma:

A

Most common skin cancer
Shiny, pearly appearance
Telangiectasias

120
Q

Dx of basal cell?

A

Shave or punch biopsy

121
Q

Tx of basal cell?

A
Surgical removal
Mohs microsurgery (instant frozen section and stop when margin is clean)
122
Q

Describe Kaposi’s sarcoma:

A

Purplish lesions on skin

Usually in HIV pts with CD4

123
Q

Tx of Kaposi’s?

A
  • Start antiretroviral therapy and raise CD4 count

- Adriamycin and vinblastine (both specific therapy for Kaposi’s)

124
Q

Describe psoriasis:

A

Silvery scales on extensor surfaces
Nail pitting
Can be extensive

125
Q

Treatment of psoriasis?

A

Emollients (Eucerin, lubriderm, vaseline, etc)
Topical vitamin A (Tazarotene)
Topical Vitamin D (Calcipotriene)
Methotrexate for severe, widespread disease

Newest therapies are etanercept, infliximab, efalizumab

126
Q

Describe atopic dermatitis

A

Red, itchy plaques
Flexor surfaces
High IgE levels

127
Q

Treatment of atopic dermatitis:

A

Preventive - emollients and avoid hot water/drying soaps

Active disease - Topical steroids, antihistamines, phototherapy, avoid scratching

128
Q

Describe seborrheic dermatitis

A
  • Oversecretion of sebaceous material from a hypersensitivity reaction to superficial fungal organism, pityrosporum ovale
  • Dandruff
  • Scaly, greasy flaky skin on a red base on scalp, eyebrows, and nasolabial fold
  • Cradle cap in infants
129
Q

Treatment for seborrheic dermatitis:

A
  • Topical hydrocortisone
  • Topical ketoconazole or selenium sulfide
  • Zinc pyrithione as a shampoo
130
Q

What is stasis dermatitis?

A
  • Hyperpigmentation from built-up hemosiderin
  • Occurs from chronic LE-venous insufficiency
  • Irreversible
131
Q

Tx of stasis dermatitis?

A

Prevent progression with elevation of legs + compression

132
Q

Describe contact dermatitis:

A
  • Hypersensitivity to soaps, detergents, latex, jewelry

- Linear streaked vesicles (esp when from poison ivy)

133
Q

How to definitively diagnose contact dermatitis?

A

Patch testing

134
Q

Treatment of contact dermatitis?

A

Antihistamines and topical steroids

135
Q

Describe pityriasis rosea:

A

Pruritic eruption that begins with herald patch (75% of the time)
Erythematous, salmon-colored
Looks like secondary syphilis (spares palms and soles though)

136
Q

Tx of pityriasis rosea?

A

Self-limited
Will resolve in 8 weeks
Caused by HSV 6 and 7 (same that cause roseola)

137
Q

Treatment of mild acne:

A

Topical clindamycin, erythromycin

Topical retinoids

138
Q

Treatment of moderate acne:

A

Benzoyl peroxide + retinoids (tazarotene, tretinoin)

139
Q

Tx of severe, cystic acne:

A

Oral minocycline, tetracycline, clindamycin, isotretinoin

140
Q

What to do before starting an oral retinoic acid derivative?

A

Pregnancy test

Make sure pts are on OCPs if female of childbearing age