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USMLE STEP 1 > Derm > Flashcards

Derm Flashcards

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USMLE® Step 1 flashcards
1
Q

Layers of the Epidermis

A 
"Californians Like Girls in String Bikinis"
Stratum Corneum (keratin)
Stratum Lucidum
Stratum Granulosum
Stratum Spinosum (spines = desmosomes)
Stratum Basale (stem cell site)
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2
Q

Sebaceous gland
What kind of gland?
What does it secrete?
What is it associated with?

A

Holocrine (cell rupture) secretion of sebum associated with hair follicle

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3
Q

Eccrine gland
What does it secrete?
Where are they located?

A

Secret sweat

Found Everywhere

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4
Q 
Apocrine gland
What does it secrete?
Where are they located?
When does it begin functioning?
How are they different from eccrine glands sensory-wise? Why?
A

Secretes milky viscous fluid
Found in axillae, genitalia, and areolae
Does not become functional until puberty
Malodorous because of bacterial action

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5
Q

Tight Junctions
Name
Function
Composition

A

Zona Occludens
Prevents paracellular movement of solutes
Claudins and Occludins

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6
Q 
Adherens Junctions 
Name
Location
What does it form?
Composition
Association with disease?
A

Zona Adherens
Below tight junctions
Forms belt connection actin cytoskeletons of adjacent cells
CADherins (Ca dependent ADhesion proteins)
Loss of E cadherin promotes metastasis

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7
Q 
Desmosomes 
Name
Function
Composition
Disease involving them?
A

Macula Adherens
Structural support
Desmoplakin and Keratin
Autoantibodies –> pemphigus vulgaris

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8
Q

Gap Junctions
Composition
Function

A

Connexons (channel proteins)

Permit electrical and chemical communication

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9
Q

Hemidesmosomes
Function
Composition
Disease involving them?

A

Connect keratin in basal cells to underlying basement membrane
Integrins in cell bind Laminin in BM
Autoantibodies –> Bullous Pemphigoid

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10
Q

SLE
Epidemiology
Presentation
Common cause of death?

A

90% are female 14-45. Most common and severe in blacks
Fever, Fatigue, Wt Loss, Libman-Sacks Endocarditis, Hilar adenopathy, Raynaud Phenomenon
Nephritis is common cause of death
Nephritic: DPGN, Nephrotic: Membranous

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11
Q

Libman-Sacks Endocarditis

A

Verrucous wart-like sterile vegetations on both sides of valve

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12
Q

Lab results in SLE

A

False + on Syphilis test (RPR/VDRL) due to antiphospholipid Abs which cross react with cardiolipin used in test
ANA (sensitive but not specific)
Anti dsDNA (specific, poor prognosis)
Anti Smith Ab (specific, not prognostic)
Anti Histone Ab (sensitive for drug induced lupus)

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13
Q

Presentation of SLE

A

“I’m DAMN SHARP”
Immunoglobins (dsDNA, Smith, Phospholipids)
Malar Rash
Discoid Rash, ANA, Mucositis (oropharyngeal ulcers), Neurological disorder
Serositis (pleuritis, pericarditis), Hematologic disorders, Arthritis, Renal disorders, Photosensitivity

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14
Q 
Sarcoidosis 
Epidemiology  
Findings 
Labs
Histo
A

Black females
Enlarged bilateral hilar adenopathy or reticular opacities on CXR
↑ ACE levels, ↑ Ca (elevated 1α hydroxylase mediated VitD activation in epithelioid Macs)
Noncaseating Granulomas

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15
Q

Sarcoidosis
Symptoms
Associated with what disease?
Treatment

A

“A Red BUG”
Often asymptomatic. Erythema Nodosum, Bell’s Palsey, Epithelial Granulomas containing microscopic Schaumann and Asteroid Bodies, Uveitis
Associated with Restrictive Lung disease (interstitial fibrosis)
Steroids

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16
Q 
Scleroderma 
Characterization
Presentation 
Other organ systems involved?
Epidemiology 
Types
A

Excessive fibrosis and collagen deposition throughout body
Commonly sclerosis of skin manifesting as puffy and taut skin w/o wrinkles
Sclerosis of Renal, Pulmonary (most common cause of death), CV, GI systems
75% females
Diffuse vs CREST

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17
Q

Diffuse Scleroderma
Presentation
Progressive
Labs

A

Widespread skin involvement
Rapid progression with early visceral involvement
Anti Scl70 Ab (anti DNA topoisomerase I)

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18
Q 
CREST Syndrome 
Name
Areas involved 
Prognosis
Labs
A

Calcinosis, Raynaud’s phenomenon, Esophageal dismotility (b/c of fibrous replacement of muscularis), Sclerodactyly, Telangiectasia
Limited skin involvement (Fingers and Face)
Benign clinical course
Anti Centromere Ab

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19
Q

Macule

A

Flat lesion w/ well circumscribed change in skin color

<5mm

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20
Q

Patch

A

Macule >5mm

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21
Q

Papule

A

Elevated solid skin lesion <5mm

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22
Q

Plaque

A

Papule >5mm

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23
Q

Vesicle

A

Small fluid containing blister <5mm

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24
Q

Bulla

A

Large fluid containing blister >5mm

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25
Q

Pustule

A

Vesicle containing pus

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26
Q

Wheal

A

Transient smooth papule or plaque (Hives)

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27
Q

Scale

A

Flaking off of stratum corneum

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28
Q

Crust

A

Dry exudate

29
Q

Hyperkeratosis

A

Thickening of stratum corneum

30
Q

Parakeratosis

A

Hyperkeratosis with retention of nuclei in stratum corneum

31
Q

Acantholysis

A

Separation of epidermal cells

32
Q

Acanthosis

A

Epidermal hyperplasia (↑ spinosum)

33
Q

Dermatitis

A

Inflammation of the skin

34
Q

Albinism
What is it?
Causes

A

Normal melanocyte # with ↓ melanin production

↓ Tyrosinase activity or failure of neural crest cell migration during development

35
Q

Melasma (Chloasma)

A

Hyperpigmentation associated with pregnancy or OCP use

36
Q

Vitiligo

A

irregular areas of complete depigmentation caused by ↓ in melanocytes

37
Q 
Verrucae 
What is it?
Causes by
Description 
PathoPhys
If on genitals
A

Warts
HPV
Soft, tan colored, cauliflower-like papules
Epidermal hyperplasia, Hyperkeratosis, Koilocytosis
Condyloma Acuminatum on genitals

38
Q

Melanocytic nevus
What is it?
Malignant?
Location and description?

A

Common mole
Benign but melanoma can arise in congenital or atypical moles
Intradermal nevi are papular. Junctional nevi are flat macules

39
Q

Urticaria
What is it?
PathoPhys

A

Hive

Pruritic wheal that forms after mast cell degranulation

40
Q

Ephelis
What is it?
Physiology

A

Freckle

Normal # of melanocytes with ↑ melanin pigment

41
Q 
Atopic Dermatitis 
What is it?
Common location 
Associated with what other diseases
Course
A

Eczema. Pruritic eruptions
Commonly on skin flexures
Associated with other atopic disease (asthma, allergic rhinitis)
Usually starts on the face during infancy and often appears in the antecubital fossae thereafter

42
Q

Allergic Contact Dermatitis
Type of Rxn
Location

A

Type IV hypersensitivity reaction following exposure to allergen
Lesions occur at site of contact

43
Q 
Psoriasis 
What is it?
Where is it?
Histo
Physical Exam findings 
Associations
A

Papules and Plaques with silvery scaling
Knees and Elbows
Acanthosis with parakeratotic scaling (nuclei still in stratum corneum).
↑ Stratum spinosum, ↓ Stratum granulosum
Auspitz sign (pinpoint bleeding spots from exposed dermal papillae when sclaes are scraped off)
Associated with nail pitting and psoriatic arthritis

44
Q 
Seborrheic Keratosis
What is it?
Appearance
Location
Malignant
Age of pt?
A 
Flat, Greasy, Pigmented Squamous Epithelial Proliferation with keratin filled cysts (horn cysts)
Looks stuck on
Head, trunk, extremities 
Benign neoplasm 
Older persons
45
Q

Leser Trelat Sign

A

Sudden appearance of multiple seborrheic keratoses indicating an underlying malignancy (GI, lymphoid)

46
Q

Pemphigus Vulgaris
PathoPhys
If
Presentation

A

IgG Abs against desmoglein 1 +/or 3 (part of desmosome)
If reveals Abs around epidermal cells in reticular or netlike pattern
Acantholysis - Intraepidermal bullae causing flaccid blister involving skin and oral mucosa. + Nikolsky Sign

47
Q

Nikolsky Sign

A

Separating of epidermis upon manual stroking of skin

Means that the lesion is intraepidermal

48
Q 
Bullous Pemphigoid 
PathoPhys
If
Histo
Presentation
A 
IgG Abs against hemidesmosomes 
Linear If
Eosinophils within tense border
Affects skin but not oral mucosa
- Nikolsky sign
49
Q

Dermatitis Herpetiformis
What is it?
PathoPhys
Associated with what disease?

A

Pruritic papules, vesicles, and bullae
Deposits of IgA at tips of dermal papillae
Associated w/ celiac disease

50
Q

Erythema Multiforme
What causes it
Presentation

A

Infections (Mycoplasma pneumoniae, HSV), Drugs (sulfa, β lactams, phenytoin), Cancer, Autoimmune
Presents with macules, papules, vesicles, target lesions (targets with multiple rings and dusky center showing multiple epithelial disruption)

51
Q 
Stevens-Johnson Syndrome 
Presentation 
Danger
Description of lesions
Caused by
Severe form
A

Fever, Bulla, Necrosis, Sloughing off of skin
High mortality rate
Typically 2 mucus membranes are involved. Lesions may appear like targets as seen in erythema multiforme
Adverse drug reaction
More severe form is toxic epidermal necrolysis

52
Q 
Acanthosis Nigricans 
PathoPhys
Description 
Location
Diseases associated with it?
A

Epidermal hyperplasia causing symmetrical hyperpigmented, velvety thickening of skin
Neck and axilla
Hyperinsulinemia (diabetes, obesity, Cushing’s) and visceral cancer

53
Q 
Actinic Keratosis
Malignant?
What causes it?
Description 
Risk of...
A

Premalignant lesion caused by sun exposure
Small, rough, scaley erythematous or brownish papules or plaques
Risk of squamous cell carcinoma proportional to degree of epithelial dysplasia

54
Q

Erythema Nodosum
PathoPhys
Location
Associated with what disorders?

A

Inflammatory lesions of subcutaneous fat
Anterior shins
Sarcoidosis, Coccidioidomycosis, Histoplasmosis, TB, Streptococcal infection, Leprosy, Crohn’s Disease

55
Q

Lichen Planus
Description
Histo
Associated with what other diseases?

A

Pruritic, Purple, Polygonal, Planar, Papules and Plaques
Sawtooth infiltrate of lymphocytes at dermal-epidermal junction
HCV

56
Q

Pityriasis Rosea
Course
Description

A

Herald Patch followed days later by Christmas tree distribution. Self-resolving in 6-8 weeks
Multiple plaques with collarette scales

57
Q

Sunburn
PathoPhys
Kind of UV light
What can in lead to?

A

UV irradiation causes DNA mutations inducing apoptosis of keratinocytes
UVA is dominant in tanning and photoaging
UVB is dominant in sunburn
Can lead to impetigo and skin cancers (basal cell carcinoma, squamous cell carcinoma, and melanoma)

58
Q 
Impetigo
What is it?
What causes it?
Epidemiology 
Presentation
A

Very superficial skin infection
S aureus or S pyogenes
Highly contagious
Honey colored crusting

59
Q

Bullous Impetigo

A

Bullae caused by S aureus

60
Q 
Cellulitis 
What is it?
Presentation 
Caused by?
Course
A

Spreading infection of dermis and subcutaneous tissues
Acute and painful
S pyogenes or S aureus
Often starts with break in skin from trauma or another infection

61
Q

Necrotizing fasciitis
What is it?
What causes it?
Presentation

A

Deeper tissue injury
Anaerobic bacteria or S pyogenes. “Flesh eating bacteria”
Crepitus from methane and CO2 production
Bullae and purple colored skin

62
Q

Staphylococcal scalded skin syndrome (SSSS)
PathoPhys
Presentation
Classic Pt?

A

Exotoxin destroys keratinocyte attachment in the stratum granulosum only
Fever and generalized erythematous rash with sloughing of the upper layers of the epidermis that heals completely
Newborns and children

63
Q

Toxic Epidermal Necrolysis

A

Exotoxin destroys epidermal-dermal junction

64
Q

Hairy Leukoplakia
What is it?
What causes it?
What kind of pt gets it?

A

White, painless, plaques on the tongue that cannot be scraped off
EBV
HIV+ pt

65
Q 
Basal Cell Carcinoma 
Frequency 
Location
Invasion? Metastatic?
Presentation 
Secondary presentation?
Histo
A

Most common skin cancer
Sun exposed areas
Locally invasive but almost never metastasizes
Pink, Pearly nodules commonly w/ telangiectasias, rolled border, central crusting or ulceration
Also appears as nonhealing ulcer with infiltrating growth or a scaling plaque
Palisading nuclei

66
Q 
Squamous Cell Carcinoma 
Frequency 
What causes it?
Location
Invasion? Metastatic?
Presentation 
Associated w/
Histo
A

2nd most common skin cancer
Sun exposure, immunosuppression, arsenic exposure
Face, lower lip, ears, hands
Locally invasive but may spread to lymph nodes and will rarely metastasize
Ulcerative red lesions with frequent scales
Associated with chronic draining sinuses
Keratin pearls

67
Q

Keratoacanthoma

A

Variant of Actinic Keratosis that grows rapidly (4-6 weeks) and may regress spontaneously over months

68
Q 
Melanoma 
Metastatic?
Marker?
Risk factors?
Presentation
A

Depth of tumor correlates with metastasis
S-100
Sunlight exposure. Fair skinned persons
Asymmetry, Border irregularity, Color variation, Diameter > 6mm, Evolution over time

69
Q

Melanoma
Genetics
Treatment

A

BRAF kinase mutation. BRAF V600E is metastatic and unresectable.
Excision with appropriately wide margins. BRAF V600E: use Vemurafenib or BRAF kinase inhibitors

USMLE STEP 1 (25 decks)

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