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USMLE Step 2 CK > Dermatology > Flashcards

Dermatology Flashcards

Know Dermatology

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USMLE® Step 1 flashcards
1
Q

Skin has 3 layers, what are they?

A

Epidermis
Dermis
Subcutaneous Tissue

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2
Q

Atopic Dermatitis

Eczema

A

Relapsing inflammatory skin disorder

ITCH THAT RASHES

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3
Q

Atopic Dermatitis characterized by?

A

Pruritus that leads to lichenification

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4
Q

Atopic Dermatitis Hx/Pe

A

Associated with:

Asthma
Allergic Rhinitis

Risk of bacterial and viral infections

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5
Q

Atopic Dermatitis Triggers

A 
Climate
Food
Allergens
Physical / Chemical irritants
Emotional Factors
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6
Q

Macule

A

Flat lesions that differers in colour from surrounding skin

<1 cm diameter

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7
Q

Papule

A

Elevated solid lesion <5mm

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8
Q

Patch

A

Small circumscribed area differing in colour from surrounding surface >1cm

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9
Q

Plaque

A

Elevated solid lesion >5mm

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10
Q

Cyst

A

Epithelial lines sac containing fluid

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11
Q

Vesicle

A

Fluid filling, very small <.5mm elevated lesion

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12
Q

Bulla

A

Large vesicle >5mm

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13
Q

Wheal (hive)

A

Area of localized edema that follows vascular leakage and usually disappears within hours

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14
Q

Lichenification

A

Thickening of the epidermis

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15
Q

Scar

A

Healing defect of the dermis

The Epidermis alone heals without a scar

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16
Q

Hypersensitivity Reaction

Type I

A

Anaphylactic or Atopic

  • Antigen cross-links IgE on PREsensitized mast cells and basophils

Triggers release of vasoactive amines (Histamine)

First and Fast

Examples- Anaphylaxis

           - Asthma
           - Wheals

Types I, II and III are all antibody or B-cell mediated

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17
Q

Hypersensitivity Reaction

Type II

A

Cytotoxic

  • IgM and IgG bind to antigen on “enemy cell” leading to Lysis (by compliment) or phagocytosis.

Examples- Autoimmune Hemolytic Anemia

           - Rh Disease
           - GoodPastures
           - Rheumatic Fever

CY-2-Toxic

Antibody and complement lead to MAC

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18
Q

Hypersensitivity Reaction

Type III

A

Immune Complex

Antigen-Antibody complex activate complement which attracts Neutrophils. Neutrophils release lysosomal enzymes

Examples:  Polyarteritis nodosa
                  SLE
                  Rheumatoid Arthritis
                  Serum Sickness (Blood)
                  Arthus Reaction (Vaccines)
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19
Q

Hypersensitivity Reaction

IV

A

Delayed (Cell Mediated)

Sensitized T lymphocytes encounter antigen and then release lymphokines (macrophage activation).

Examples: TB skin test
Transplant rejection
Contact dematitis

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20
Q

Atopic Dermatitis Dx

A

Made clinically

Mild eosinophilia
Increase IgE

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21
Q

Atopic Dermatitis Tx

A

Prophylactic measures

  • non-drying soap
  • Apply Moisturizers

Treat with topical steroids (don’t use longer than 3 weeks)

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22
Q

Contact Dermatitis

A

Type IV hypersensitivity Reaction

Results from contact with allergen which the pt has had previously been exposed and sensitized too

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23
Q

Contact Dermatitis Hx / PE

A

rash and pruritus

Allergens frequently include:

  • poison ivy
  • poison Oak
  • Nickel
  • Soaps
  • Detergents
  • Cosmetics
  • Rubber Latex

Occurs where allergen touches

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24
Q

Contact Dermatitis Tx

A

Prophylaxis consists of Avoidance

Give- Topical or systemic steroids as needed
- wet, cool compresses to relieve and debride the skin

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25
Q

Seborrheic Dermatitis

A

Caused by Pityrosporum Ovale

A harmless yeast found in sebum and hair collicles

Predilection for areas with Oily skin such as
(Scalp, eyebrows, nasolabial folds and mid chest)

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26
Q

Seborrheic Dermatitis Hx/PE

A

Rash varies with Age

Infants- Red diaper rash

      - Yellow scale
      - thick crust (cradle Cap)

Children / Adults- Red, Scaly Patches
- ears, brows, scalp, chest

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27
Q

Seborrheic Dermatitis Dx

A

Clinical impression

Rule out Contact dermatitis and psoriasis

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28
Q

Seborrheic Dermatitis Tx

A

Selenium Sulfide
or
Zinc Pyrithione shampoo

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29
Q

Psoriasis

A

T-cell mediated inflammatory dermatosis

Character:

  • Erthematous patches
  • Silvery Scales
  • 5% have seronegative arthritis
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30
Q

Psoriasis Hx / PE

A

Lesions

  • Round, sharp boardered
  • Erthematous patch with silvery scales
  • Found on Extensor surface
    - elbows
    - knees
    - scalp

Other causing Reasons

  • BB
  • Lithium
  • ACE-I
  • Strep infection
  • Trauma

Psoriatic Arthritis

  • Begins with hands “sausage digits”
  • HLA- 27 for spinal involvement
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31
Q

Psoriasis Dx

A
  • Clinical impression
  • Auspitz sign (bleeding when scale is scraped)
  • Histo shows thickend Epidermis and infiltrate in stratum corneum
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32
Q

Psoriasis Tx

A

Topical steroids combined with Keratolytic agents and UV therapy

Methotrexate for severe cases
Retinoids may also be used

Arthritis treated with NSAIDs

AVOID Systemic steroids

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33
Q

Urticaria (Hives)

A

Superficial, Intense Edema in a localized area

Usually acute

Type I Hypersensitivity

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34
Q

Urticaria (Hives) Hx / PE

A

Range in severity

  • few itch bumps
  • life threatening anaphylaxis

Lesion

  • Elevated papule or plaque
  • Reddish or white

Severe Rx

  • swelling of tongue
  • AngioEdema
  • Asthma
  • Fever
  • GI Issues
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35
Q

Urticaria (Hives) Dx

A

Clinical impression

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36
Q

Urticaria Tx

A

Systemic Antihistamines

Topical medications have NO Benifit

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37
Q

Drug Eruption

A

Eruptions like rashes, SLE like symptom

Happens after 7-14 days of starting new drug

If happens <7 days probably not drug

Tx- Antihistamines

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38
Q

Erythema Multiforme

A

Classic targetoid lesions

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39
Q

Erythema Multiforme Hx / PE

A

Lesion has Target Appearance

Occurs on Mucus Membrane where erosions are seen

Palms and soles also affected

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40
Q

Erythema Multiforme Dx and Tx

A

Clinical impression

History of recurrent labial herpes

Tx- symptomatic tx ONLY

HSV- suppressive acyclovir may decrease the rash

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41
Q

Stevens-Johnson Syndrome (SJS)

Toxic Epidermal Necrolysis (TEN)

A

SJS & TEN constitute two different points on the spectrum of life threatening

SJS = 30% of BSA

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42
Q

SJS and TEN Hx

A 
Preceded by Erythema Multiforme
Painful mouth rash
Maculopapular drug rash
    - Penicilin
    - Sulfonamides
    - Seizure meds

Exam reveals

  • Mucosal erosions
  • Cutaneous Macules
  • Atypical Targetoid Leions

+ Nikolsky’s Sign = Epidermal detachment

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43
Q

SJS & TEN Diagnosis

A

SJS= Biopsy shows Degeneration of basal layer of epidermis

TEN= Biopsy shows full-thickness eosinophilic epidermal necrosis

SSSS- ONLY is SUPERFICIAL damage

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44
Q

SJS & TEN Treatment

A

Same complications as burn victims
Thermoregularory difficulties
Electrolyte disturbances

TX- skin coverage
- maintain fluid and electrolyte balance

High risk of mortality

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45
Q

Erythema Nodosum

A

Panniculitis whose triggers include

  • Infections
  • Drug Reactions
  • Chronic inflammatory disease
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46
Q

Erythema Nodosum Hx

A

Painful erythematous nodules on lower legs

Spread slowly

turns brown or gray

Fever and joint pain

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47
Q

Erythema Nodosum Dx and Tx

A

Clinical impression

Workup

  • ASO
  • PPD
  • CXR to rule out carcoid
  • Small Bowl (rule out IBD)

Tx- Remove trigger factors
- NSAIDs

48
Q

Pemphigus Vulgaris

A

LIfe Threatening Autoimmune Disease

Intraepidermal Blister Leading to Widespread Painful erosisons

Antibodies directed at DESMOGLEIN molecules

Usually 40 - 60 years old

49
Q

Pemphius Vulgaris Hx / PE

A

Mucous Membrane involvement (mouth ulcers) with progress to skin

Gets crust and weeping and 2 infection

50
Q

Pemphius Vulgaris Dx

A

+ Nikolsky’s Sign (ability to produce a blister by rubbing skin adjacent to natural blister)

Skin Biopsy with immunofluorescence confirms

Biopsy shows acantholysis (intraepidermal split with free-floating keratinocyctes in blisters)

51
Q

Pemphius Vulgaris Tx

A

Long term needed

  • Steroids at high doses
52
Q

Bullous Pemphigoid

A

Acquired blistering disease

Seperation of epidermal basement membrane

Seen 60 - 80 year olds

Pathology is antibodies by the basement membranes

53
Q

Bullous Pemphigoid Hx / PE

A

Nikolsky’s Sign -

Blisters form crusts and erosions

No mouth ulcers

Leaves Mucous Membranes alone

54
Q

Bullous Pemphigoid Tx

A

Systemic Steroids

Topical Steroids can prevent blisters if started early

55
Q

Bullous Pephigoid Diagnosis

A

Dermal-Epidermal junction

56
Q

Herpes Simplex Virus Dx

A

Multinucleated Giant Cells on Tzanck Smears

VZV has same appearance on Tancks so Direct Fluorescent antibody staining needed for definitive diagnosis

57
Q

HSV Tx

A

Oral or IV Acyclovir reduct severity or recurrences

Acyclovir ointment reduces duration of cirual shedding but not recurrence

58
Q

Varicella-Zoster Virus (VZV)

2 Diseases associated?

Transmits how?

Incubation period?
Contagious for how long?

A

Causes 2 different diseases

Varicella (Chicken Pox)
Herpes Zoster (Shingles)

Transmit via respiratory droplet or direct contact

VZV incubation - 10 - 20 days
Contagious 24 hr before eruption and lasts until lesions crusted

59
Q

Molluscum Contagisum

A

Pox Virus in young children and in AIDS pt.

Rash is composed of tiny waxy papules with central umbilication

Kids- Found on face, trunk

Adults- on Genitalia and perineal region

60
Q

Molluscum Contagiusm DX & Tx

A

Clinical picture

Local Destructive method- curetting, freezing or trichloracetic acid to lesion

Lesions resolve spontaneously over months to years and left untreated in children

61
Q

Verrucae (Warts)

Which cause cancer and what type?

how spread?

A

Subtypes of HPV 16 and 18 lead to squamous malignancies

Spread by direct contact

62
Q

warts and Genital Warts Tx

A

WARTS:
Curettage
Cryotherapy
Acid Keratolytics

Gential
- Podophyllin
Ticholoacetic acid
Imiquimod
5-FU
Genital
63
Q

Impetigo

What bacteria?
How transmitted?
2 types?

A

Group A strep and Staph

Transmitted by direct contact

Types:

  • Common
  • Bullous
64
Q

Impetigo Hx / PE

A

Common- pustules and honey coloured crusts usually on face

Bullous- Acral, large stable blisters (always caused by S. Aureus)

65
Q

Scarlet Fever

what it look like?

Caused by?

Tx?

A

“Sunburn with goosebumps”

Strawberry tongue

Caused by S. Pyogenes

Tx- PCN

66
Q

Cellulitis

A

Deep, local infection involving connective tissue, subQ tissue or muscle and skin

67
Q

Cellulitis caused by what organisms (2)

Risk factors?

A

Staph

Group A Strep

Risk factors:

  • DM
  • IV drug use
  • Venous Stasis
  • Immune compromise
68
Q

Cellulitis

Tx:

A

7 - 10 days oral antibiotics (Mild cases)

IV Antibiotics (systemic toxicity or comorbid conditions, orbital or hand involvement)

69
Q

Acne Vulgaris

Cause?

A

Endogenous skin disease in adolescents

Hormonal activation of sebaceous glands

develops comedo or plugged sebaceous follicle

70
Q

Acne Vulgaris

HX / PE

A

Comedo (Open- Blackheads) or (Closed- whiteheads), large numbers but no inflammation

Inflammatory- Comedo ruptures creating pustule thats large and nodular

Scar- inflammtion heals and scars

71
Q

Acne Vulgaris Tx

A

Comedones- Topical TRETINOIN (Retin-A) and Benzoyl Peroxide

Inflammatory- Topical antibiotics (erythromycin, clindamycin) or
- Systemic Agents- Tetracycline or erythromycin

72
Q

Pilonidal Cysts

How does it start then what microbe happens

A

Abscess in sacrococcygeal region, near top of natal cleft

Repetitive trauma plays a role

Starts as folliculitis and abscess from perineal microbe- bacteroides

Occurs 20 - 40 year old

73
Q

Pilonidal Cyts Tx

A

Incision and Drainage ( I & C ) under local anesthesia then

Steile Packing of wound

Abcesses should be healed by 2nd Intention

No Antibiotics since abcess are anerobic

74
Q

Tinea Versicolor

What bacteria causes it?
Why does it go out of control?

A

Caused by Malassezia Furfur (yeast of normal skin)

Hot, humid and oily skin causes it to overgrow

75
Q

Tinea Versicolor HX / PE

A

Small, scaly patches of varying color on chest or back

Lesions hypopigmented as a result of interference with melanin production

Hyperpigmented due to thickened scale

76
Q

Tinea Versicolor Dx

A

Clinical Impression

Confirmed by Potassium hydroxide (KOH) preparation of scale “Speghetti and meatball pattern”

77
Q

Tinea Versicolor Tx

A

Topical Selenium Sulfide daily for 1 week

Then applicaiton once weekly for prophylaxis

78
Q

Dermatophyte Infections

Live where?

Organisms?

Risk factor?

A

Live only in tissue with keratin (Skin, nails, hair)

Organisms
- Microsporum, Trichophyton, Epidermophyton

Risk Factors

  • Pets reservoir for Microsporum
  • DM
79
Q

Dermatophyte Infections

HX / PE

Tinea Corporis
Tinea Pedis / Manuum

Tinea Curis
Tinea Capital

A

Tinea Corporis

  • scaly
  • Pruritic eruption
  • Sharp, irregular boarder with central clearing

Tinea Pedis / Manuum

  • interdigital scaling
  • Erosions between toes
  • Tick scaly skin on soles
  • Asymmetric involvement of hands

Tinea Cruris

  • Jock Itch
  • Sparms scrotum

Tinea Capitis

  • Ringworm
  • Scaly scalp eruption
80
Q

Lice

Head
Body
Pubic

How spread?

A

Live off Blood

Head louse

  • lives on scalp
  • lays eggs “Nits” attached to hair

Body Louse
- Lives in clothing and bites ONLY body

Public Louse

  • Lives on pubic hair
  • “Crabs”

Spread through body contact or sharing bedclothes and garments

Secrete toxin that creates pruritis

81
Q

Lice HX / PE

A

Crabs- contain anticoagulant in Saliva so bites turn blue

Body Lice- from inadequate hygene or crowded living

82
Q

Lice Tx

A

Head- OTC Pyrethrin and mechanical removal of nits

Body- Wash body, clothes and bedding
- body gets permethrin or Pyrethrin (RID)

Pubic- Treat with Pyrethin (RID)

83
Q

Scabies

Organism

Spreads?

What causes pruritis

A

Organism- Sarcoptes Scabiei

Mates on skin after which the female digs passage into Stratum Corneum and lays eggs

Burrowing leads to pruritus

Spead by close contact

84
Q

Scabies Hx / PE

A

Intense pruritus at night or hot showers

Affected- Hands, axillae and genitals and Creases in skin

85
Q

Scabies Tx

A

1 - 2 applications of 5% Permethrin from neck down

Oral Ivermectin also effective

Itching lasts 2 weeks after treatment

86
Q

Lichen Planus

What is it?

A

Chronic inflammatory dermatosis involving the skin and mucous membranes

Extremely Pruritic

87
Q

Lichen Planus Hx / PE

A

Presents with:

  • Violaceous, flat opped, polygonal papules
  • White stripes
  • Initial lesions appear on the genitalia- ulcerated
88
Q

Lichen Planus Dx

A

Histology reveals Lichenoid pattern

- band of T-lymphocytes at the epidermal junction with damage to the basal layer

89
Q

Lichen Planus Tx

A

Resolves in 12 months

Mild cases- topical steroids

Severe- Systemic steroids

90
Q

Pityriasis Rosea

what is it?

A

Acute dermatitis that is pink and scaly

Occurs in young adults

91
Q

Pityriasis Rosea

Hx / PE

A

Initial lesion is herald patch that is several cm.

  • Days / weeks later, got a christmas tree pattern on patients back
  • usually asymptomatic
92
Q

Pityriasis Rosea

Dx and Tx

A

clinical impression

confirmed by KOH exam to rule out fungus

Tx- no treatment, heals in 2-3 weeks

93
Q

Vitiligo

A

Depigmentation pathogenesis is unknown

94
Q

Vitiligo Hx / PE

A

develop small, sharply demaracted depigmented macules or patches on normal skin.

usually chronic and progressive

Many have serum markers of autoimmune disease (thyroid, dm, pernicious anemia)

95
Q

Vitiligo

DX & Tx

A

History and clinical

Tx- topical or systemic Psoralens
- exposure to light

96
Q

Seborrheic Keratosis

A

Skin tumor, in all people after 40 y/o

Lesions have NO malignant potential

97
Q

Seborrheic Keratosis

Hx / PE

A

Exophytic
Waxy brown papules and plaques
“stuck on appearance”
usually comes in bunches

98
Q

Seborrheic Keratosis

Dx & Tx

A

Clinical

Histology shows Hyperplasia of benign, basaloid epidermal cells with horn pseudocyts.

Tx- Cryotherapy or curettage curative

99
Q

Actinic Keratosis

A

Precursor of SCC in Situ

Lesions caused by exposure to sunlight

100
Q

Actinic Keratosis

HX / PE

A

Appear on sun-exposed area (face and arms)

Affect older pt.

Rare to have solitary lesion

101
Q

Actinic Keratosis

Dx & Tx

A

Clinical

Biopsy- intraepidermal atypia over sun damaged dermis

Tx- Cryosurgery
Topical 5-FU

Use Sun Protection

102
Q

Squamous Cell Carcinoma (SCC)

A

Second most common skin tumor

Locally destructive effects and potential for metastasis and death

UV Light most common cause

103
Q

SCC

Hx / PE

A

Arises from Actinic Keratoses rarely metastasize

Those around lips are more liekly to do so.

SCC occurs on the lip more commonly than BCC

104
Q

SCC Dx & Tx

A

Biopsy confirms

Histology- Intraepidermal atypical keratinocytes with penetration of basement membrane by malignant epidermal cells growing into dermis

TX- Surgical excision

105
Q

Basal Cell Carcinoma (BCC)

A

Most common malignant skin tumor

Slow growing
Locally destructive
NO Metastatic potential

Chronic UV light is risk factor

Most appear on face

106
Q

BCC

Hx / PE & Tx

A

Isalnds of proliferating epithelium resembling the basal layer of the epidermis

Pearly papule

Tx- Excision

107
Q

Melanoma

A

Most common life threatening dermatologic disease

Risks- Short intense burts of sun exposure

108
Q

Melanoma

Hx / PE

A

Malignant melanoms usually begin in Epidermal Basal layer where melanocytes found

1st growth- horizontal intraepidermal

Presents with lesion that is flat but increase diamter

2nd growth- vertical with dermal invasion

109
Q

Melanoma

ABCDE

A 
Asymmetric
irregular Boarder
irregular Colour
Diameter > 6mm
Evolution- change or new lesion
110
Q

Melanoma

DX

A

Adutls should be examined for lesions

Onset of puritis is also an early sign of malignant change

Excisional biopsy should be done on any suspicious lesions

Stage

111
Q

Melanoma Stage

A

Breslow’s Thickness (depth of invasion in mm)

TNM Staging
1- 1st skin melanoma 70% survival 5 years
2- local or regional 30% survival 5 years
3- Distant Metastisis 0 % survival 5 years

112
Q

Melanoma Tx

A

Potential to relapse after several years

Early melanoma are low risk for relapse but high risk for subsequent melanoms

Pt Surveillance is essential

Chemo and Radiation aren’t likely to be successful

113
Q

Mycosis Fungoides

Cutaneous T-cell Lymphoma

A

NOT A FUNGUS

Slow, progressive neoplastic proliferation of T-cells

Industrial exposure increases risk

Chronic disease

114
Q

Mycosis Fungoides

Hx / PE

A

Early lesion is non-specific

Psoriatic appearing plaque that is palpable and prutiric

115
Q

Mycosis Fungoides

DX / Tx

A

Clincial

Tx-
Stage 1 - Topical Steroids
II- Systemically with netinoids

Photopheresis is mainstay of treatment

USMLE Step 2 CK (5 decks)

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