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USMLE Step 2 CK > Dermatology > Flashcards

Dermatology Flashcards

Know Dermatology

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
Seborrheic Dermatitis
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)
26
Seborrheic Dermatitis Hx/PE
Rash varies with Age Infants- Red diaper rash - Yellow scale - thick crust (cradle Cap) Children / Adults- Red, Scaly Patches - ears, brows, scalp, chest
27
Seborrheic Dermatitis Dx
Clinical impression Rule out Contact dermatitis and psoriasis
28
Seborrheic Dermatitis Tx
Selenium Sulfide or Zinc Pyrithione shampoo
29
Psoriasis
T-cell mediated inflammatory dermatosis Character: - Erthematous patches - Silvery Scales - 5% have seronegative arthritis
30
Psoriasis Hx / PE
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
31
Psoriasis Dx
- Clinical impression - Auspitz sign (bleeding when scale is scraped) - Histo shows thickend Epidermis and infiltrate in stratum corneum
32
Psoriasis Tx
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
33
Urticaria (Hives)
Superficial, Intense Edema in a localized area Usually acute Type I Hypersensitivity
34
Urticaria (Hives) Hx / PE
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
35
Urticaria (Hives) Dx
Clinical impression
36
Urticaria Tx
Systemic Antihistamines Topical medications have NO Benifit
37
Drug Eruption
Eruptions like rashes, SLE like symptom Happens after 7-14 days of starting new drug If happens <7 days probably not drug Tx- Antihistamines
38
Erythema Multiforme
Classic targetoid lesions
39
Erythema Multiforme Hx / PE
Lesion has Target Appearance Occurs on Mucus Membrane where erosions are seen Palms and soles also affected
40
Erythema Multiforme Dx and Tx
Clinical impression History of recurrent labial herpes Tx- symptomatic tx ONLY HSV- suppressive acyclovir may decrease the rash
41
Stevens-Johnson Syndrome (SJS) Toxic Epidermal Necrolysis (TEN)
SJS & TEN constitute two different points on the spectrum of life threatening SJS = 30% of BSA
42
SJS and TEN Hx
``` 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
43
SJS & TEN Diagnosis
SJS= Biopsy shows Degeneration of basal layer of epidermis TEN= Biopsy shows full-thickness eosinophilic epidermal necrosis SSSS- ONLY is SUPERFICIAL damage
44
SJS & TEN Treatment
Same complications as burn victims Thermoregularory difficulties Electrolyte disturbances TX- skin coverage - maintain fluid and electrolyte balance High risk of mortality
45
Erythema Nodosum
Panniculitis whose triggers include - Infections - Drug Reactions - Chronic inflammatory disease
46
Erythema Nodosum Hx
Painful erythematous nodules on lower legs Spread slowly turns brown or gray Fever and joint pain
47
Erythema Nodosum Dx and Tx
Clinical impression Workup - ASO - PPD - CXR to rule out carcoid - Small Bowl (rule out IBD) Tx- Remove trigger factors - NSAIDs
48
Pemphigus Vulgaris
LIfe Threatening Autoimmune Disease Intraepidermal Blister Leading to Widespread Painful erosisons Antibodies directed at DESMOGLEIN molecules Usually 40 - 60 years old
49
Pemphius Vulgaris Hx / PE
Mucous Membrane involvement (mouth ulcers) with progress to skin Gets crust and weeping and 2 infection
50
Pemphius Vulgaris Dx
+ 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
Pemphius Vulgaris Tx
Long term needed - Steroids at high doses
52
Bullous Pemphigoid
Acquired blistering disease Seperation of epidermal basement membrane Seen 60 - 80 year olds Pathology is antibodies by the basement membranes
53
Bullous Pemphigoid Hx / PE
Nikolsky's Sign - Blisters form crusts and erosions No mouth ulcers Leaves Mucous Membranes alone
54
Bullous Pemphigoid Tx
Systemic Steroids Topical Steroids can prevent blisters if started early
55
Bullous Pephigoid Diagnosis
Dermal-Epidermal junction
56
Herpes Simplex Virus Dx
Multinucleated Giant Cells on Tzanck Smears VZV has same appearance on Tancks so Direct Fluorescent antibody staining needed for definitive diagnosis
57
HSV Tx
Oral or IV Acyclovir reduct severity or recurrences Acyclovir ointment reduces duration of cirual shedding but not recurrence
58
Varicella-Zoster Virus (VZV) 2 Diseases associated? Transmits how? Incubation period? Contagious for how long?
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
Molluscum Contagisum
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
Molluscum Contagiusm DX & Tx
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
Verrucae (Warts) Which cause cancer and what type? how spread?
Subtypes of HPV 16 and 18 lead to squamous malignancies Spread by direct contact
62
warts and Genital Warts Tx
WARTS: Curettage Cryotherapy Acid Keratolytics ``` Gential - Podophyllin Ticholoacetic acid Imiquimod 5-FU Genital ```
63
Impetigo What bacteria? How transmitted? 2 types?
Group A strep and Staph Transmitted by direct contact Types: - Common - Bullous
64
Impetigo Hx / PE
Common- pustules and honey coloured crusts usually on face Bullous- Acral, large stable blisters (always caused by S. Aureus)
65
Scarlet Fever what it look like? Caused by? Tx?
"Sunburn with goosebumps" Strawberry tongue Caused by S. Pyogenes Tx- PCN
66
Cellulitis
Deep, local infection involving connective tissue, subQ tissue or muscle and skin
67
Cellulitis caused by what organisms (2) Risk factors?
Staph Group A Strep Risk factors: - DM - IV drug use - Venous Stasis - Immune compromise
68
Cellulitis Tx:
7 - 10 days oral antibiotics (Mild cases) IV Antibiotics (systemic toxicity or comorbid conditions, orbital or hand involvement)
69
Acne Vulgaris Cause?
Endogenous skin disease in adolescents Hormonal activation of sebaceous glands develops comedo or plugged sebaceous follicle
70
Acne Vulgaris HX / PE
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
Acne Vulgaris Tx
Comedones- Topical TRETINOIN (Retin-A) and Benzoyl Peroxide Inflammatory- Topical antibiotics (erythromycin, clindamycin) or - Systemic Agents- Tetracycline or erythromycin
72
Pilonidal Cysts How does it start then what microbe happens
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
Pilonidal Cyts Tx
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
Tinea Versicolor What bacteria causes it? Why does it go out of control?
Caused by Malassezia Furfur (yeast of normal skin) Hot, humid and oily skin causes it to overgrow
75
Tinea Versicolor HX / PE
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
Tinea Versicolor Dx
Clinical Impression Confirmed by Potassium hydroxide (KOH) preparation of scale "Speghetti and meatball pattern"
77
Tinea Versicolor Tx
Topical Selenium Sulfide daily for 1 week Then applicaiton once weekly for prophylaxis
78
Dermatophyte Infections Live where? Organisms? Risk factor?
Live only in tissue with keratin (Skin, nails, hair) Organisms - Microsporum, Trichophyton, Epidermophyton Risk Factors - Pets reservoir for Microsporum - DM
79
Dermatophyte Infections HX / PE Tinea Corporis Tinea Pedis / Manuum Tinea Curis Tinea Capital
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
Lice Head Body Pubic How spread?
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
Lice HX / PE
Crabs- contain anticoagulant in Saliva so bites turn blue Body Lice- from inadequate hygene or crowded living
82
Lice Tx
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
Scabies Organism Spreads? What causes pruritis
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
Scabies Hx / PE
Intense pruritus at night or hot showers Affected- Hands, axillae and genitals and Creases in skin
85
Scabies Tx
1 - 2 applications of 5% Permethrin from neck down Oral Ivermectin also effective Itching lasts 2 weeks after treatment
86
Lichen Planus What is it?
Chronic inflammatory dermatosis involving the skin and mucous membranes Extremely Pruritic
87
Lichen Planus Hx / PE
Presents with: - Violaceous, flat opped, polygonal papules - White stripes - Initial lesions appear on the genitalia- ulcerated
88
Lichen Planus Dx
Histology reveals Lichenoid pattern | - band of T-lymphocytes at the epidermal junction with damage to the basal layer
89
Lichen Planus Tx
Resolves in 12 months Mild cases- topical steroids Severe- Systemic steroids
90
Pityriasis Rosea what is it?
Acute dermatitis that is pink and scaly Occurs in young adults
91
Pityriasis Rosea Hx / PE
Initial lesion is herald patch that is several cm. - Days / weeks later, got a christmas tree pattern on patients back - usually asymptomatic
92
Pityriasis Rosea Dx and Tx
clinical impression confirmed by KOH exam to rule out fungus Tx- no treatment, heals in 2-3 weeks
93
Vitiligo
Depigmentation pathogenesis is unknown
94
Vitiligo Hx / PE
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
Vitiligo DX & Tx
History and clinical Tx- topical or systemic Psoralens - exposure to light
96
Seborrheic Keratosis
Skin tumor, in all people after 40 y/o Lesions have NO malignant potential
97
Seborrheic Keratosis Hx / PE
Exophytic Waxy brown papules and plaques "stuck on appearance" usually comes in bunches
98
Seborrheic Keratosis Dx & Tx
Clinical Histology shows Hyperplasia of benign, basaloid epidermal cells with horn pseudocyts. Tx- Cryotherapy or curettage curative
99
Actinic Keratosis
Precursor of SCC in Situ Lesions caused by exposure to sunlight
100
Actinic Keratosis HX / PE
Appear on sun-exposed area (face and arms) Affect older pt. Rare to have solitary lesion
101
Actinic Keratosis Dx & Tx
Clinical Biopsy- intraepidermal atypia over sun damaged dermis Tx- Cryosurgery Topical 5-FU Use Sun Protection
102
Squamous Cell Carcinoma (SCC)
Second most common skin tumor Locally destructive effects and potential for metastasis and death UV Light most common cause
103
SCC Hx / PE
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
SCC Dx & Tx
Biopsy confirms Histology- Intraepidermal atypical keratinocytes with penetration of basement membrane by malignant epidermal cells growing into dermis TX- Surgical excision
105
Basal Cell Carcinoma (BCC)
Most common malignant skin tumor Slow growing Locally destructive NO Metastatic potential Chronic UV light is risk factor Most appear on face
106
BCC Hx / PE & Tx
Isalnds of proliferating epithelium resembling the basal layer of the epidermis Pearly papule Tx- Excision
107
Melanoma
Most common life threatening dermatologic disease Risks- Short intense burts of sun exposure
108
Melanoma Hx / PE
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
Melanoma ABCDE
``` Asymmetric irregular Boarder irregular Colour Diameter > 6mm Evolution- change or new lesion ```
110
Melanoma DX
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
Melanoma Stage
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
Melanoma Tx
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
Mycosis Fungoides | Cutaneous T-cell Lymphoma
NOT A FUNGUS Slow, progressive neoplastic proliferation of T-cells Industrial exposure increases risk Chronic disease
114
Mycosis Fungoides Hx / PE
Early lesion is non-specific | Psoriatic appearing plaque that is palpable and prutiric
115
Mycosis Fungoides DX / Tx
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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