Fitzgerald - Dermatology Flashcards

1
Q

Derm assessment questions

A

Is the patient otherwise well? = localized skin infection (acne, rosacea, kp, seborrheic derm)

Is patient miserable but not systemically ill? = uncomfortable with itch, burning, pain (severe psoriasis, Norwegian scabies, herpes zoster)

Is patient systemically ill? = Systemic disease (varicella, transepidermal necrosis, SJS/erythema multiforme, Lyme disease)

Are there primary/secondary lesions? = Where is the oldest lesion and when did it occur? Where is the newest lesion and when did it occur?

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2
Q

Primary Lesions vs Secondary

A

PRIMARY

Result from disease process. No alteration from outside manipulation/tx/natural course of disease. Eg. vesicle

SECONDARY

Lesions altered by outside manipulation/tx/course of disease. Eg. crust

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3
Q

Auspitz sign

A

Psoriasis

Pinpoint bleeding when scale is scraped off.

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4
Q

Vitiligo

A

Autoimmune against melanocytes

Common w/ other autoimmune diseases (thyroid)

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5
Q

Palpable Purpura

A

NEVER BENIGN

“blueberry muffin” appearance

e.g. Meninigitis rash

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6
Q

Macule

A

flat, nonpalpable discoloration

e.g.

Freckle

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7
Q

Papule

A

Solid elevation

e.g.

raised nevus

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8
Q

Umbilicated and example

A

Papule with indented center

e.g.

Molluscum contagiosum

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9
Q

Pustule

A

Vesicle-like lesion with purulent content

e.g.

Impetigo

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10
Q

Patch and example

A

> 1 cm

flat, nonpalpable discoloration

e.g.

Vitiligo

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11
Q

Plaque

A

> 1 cm

Raised lesion, same or different color of surrounding skin, can result from coalescence of papules

e.g.

Psoriasis

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12
Q

Bulla

A

> 1 cm

Fluid filled (bigger than vesicle)

e.g.

Necrotizing fasciitis

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13
Q

Cyst

A

Any size

Raised, enxapsulated, fluid-filled lesion

Always benign

e.g.

Intradermal cyst

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14
Q

Wheal

A

Any sized

Circumscribed area of skin edema

e.g.

Hives

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15
Q

Purpura

A

Purpura > 1 cm

Petechiae

Flat red-purple discoloration caused by RBCs lodged in the skin

Do NOT blanch

(vascular lesion = blanches)

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16
Q

Excoriation

A

Linear, raised, often covered with crust.

e.g.

scratch marks over pruritic areas

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17
Q

Crust

A

Raised lesions produced by dried serum and blood remnants

e.g.

scab

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18
Q

Lichenification

A

Skin thickening usually found over pruritic or friction areas

e.g.

Callus

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19
Q

Scales

A

Raised superficial lesiosn that flake with ease

e.g.

Dandruff

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20
Q

Erosion

A

Loss of epidermis

e.g.

area under vesicle

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21
Q

Ulcer

A

Loss of epidermis AND dermis

e.g

arterial ulcer

Chancre

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22
Q

Fissure

A

Narrow linear crack into epidermis, exposing dermis

e.g.

athletes foot

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23
Q

Annular lesion

A

In a RING

e.g.

Erythema migrans (“bull’s eye”) in Lyme disease

24
Q

Scattered lesion

A

Generalized over body w/o specific pattern or distribution

e.g.

maculopapular rash in rubella

25
Q

Confluent/coalescent lesions

A

Multiple lesions bleding together

26
Q

Clustered lesions

A

Occurring ina group with pattern

e.g.

Acne-form drug induced rash

seen with lithium, phenytoin, and iodine use = anticipated adverse effect

27
Q

Linear lesions

A

In streaks

e.g.

Contact dermatitis poison ivy

28
Q

Reticular lesions

A

Appearing in a net-like cluster

e.g.

Erythema infectiosum (Fifth Disease/slapped cheek)

29
Q

Dermatomal or zosteriform lesion

A

Limited to boundaries of a single or multiple dermatomes

e.g.

Shingles

NOTE:

If suspected, start on high-dose acyclovir and come back in 24 hours to confirm dx

Pain occurs 1-2 days before lesions erupt

Suspect in acute shoulder/back pain, skin is “sore”

Skin could also itch severely

30
Q

Varicella

A

Infants vulnerable - vaccine is given at year

2-3 mm vesicles that start on trunk, appear on limbs 2-3 days later

Nonclustered lesions at a variety of stages

Mild to moderately ill

Miserably itchy, risk for bacterial suprainfection of lesions

Tx:

Acyclovir within 24-48 hours of eruption

Prevention:

Varicella vaccine = 80% lifetime immunity first dose, 99% lifetime immunity second dose

31
Q

Zoster (shingles)

A

Typically 50 years or older

Possible in anyone with history of varicella

Vesicles in a unilateral dermatomal pattern, slowly resolving with crusting

Usually not systemically ill but quite miserable with pain and itch. Complications include postherpetic neuralgia, ophthalmologic involvement, and superimposed bacterial infection.

Tx:

High-dose acyclovir within 72 hours of eruption helps minimize duration and severity of illness

Prevention:

Zoster vaccine

32
Q

Actinic Keratoses (AK)

A

Predominantly on sun-exposed skin

Size ranges

On skin surface - red, brown, scaly, often tender but usually minimally symptomatic

Occassional flesh-colored - more easily felt than seen

Most common precancerous lesion though possibly represent early-stage SCC

1 in 100 will progress to SCC

Tx:

Topical 5-FU, 5% imiquimod cream, topical diclofenac gel or photodynamic therapy with topical delta-aminolevulinic acid

Cryosurgery w/ liquid nitrogen, laser resurfacing, chemical peel

33
Q

Basal cell carcinoma

A

More common than SCC
Sun-exposed area

Arises de novo (of new)

Papule, nodule w/ or w/o central erosion

Pearly or waxy appearance, usually relatively distinct borders w/ or w/o telengiectasia

Metastatic risk low

34
Q

Squamous cell carcinoma

A

Less common than BCC

Sun-exposed areas

Can arise from AK or de novo

Red, conical hard lesions w/ or w/o ulceration

Less distinct borders

Metastatic risk greater (3-7%)

Greatest metastatic risk = lesion on lip, oral cavity, genitalia

35
Q

ABCDE

Malignant Melanoma

A

A - Asymmetric

B - Irregular borders

C - Color not uniform

D - Diameter usually 6mm or >

E - Evolving (new) lesion or change in a longstanding lesion, particularly in a nevus or other pigmented lesion

E - Elevated (not consistently present)

* Majority of melanoma are de novo

36
Q

Psoriasis vulgaris tx

A

medium-potency topical corticosteroid

37
Q

Rosacea tx

A

Topical metronidazole

38
Q

Pityriasis rosea

A

Acute, self-limited, erythematous skin disease

Most likely viral

Herald patch

X-mas tree pattern

Prodrome might occur but typically asymptomatic aside from itching

Most cases do not require tx, may use medium-potency topical corticosteroid for itching

Acyclovir may be useful in severe disease in shortening length of disease

39
Q

Acanthosis nigricans

A

cutaneous manifestation of hyperinsulinemia

puberty = worsenign insulin resistance

can regress w/ control of disease

e.g. after gastric bypass

40
Q

Erysipelas

A

Infection of upper dermis, superficial lymphatics

Streptococcus pyogenes (aka GABHS)

41
Q

Cellulitis

A

Infection of dermis and subcutaneous fat

Streptococcus pyogenes, less commonly MSSA beta-lactamase producing, MRSA (resistance via altered protein-binding sites)

42
Q

Cutaneous abscess, furuncle

A

Skin infection involving hair follicle and surrounding tissue

Carbuncles = cluster of furuncles connected subcutaneously, causing deeper suppuration and scarring

Staph aureus (MSSA, MRSA)

43
Q

Nonpurulent skin infection

A

Necrotizing infection/Cellulitis/Erysipelas

Moderate = inpatient for IV PCN or Ceftriaxone, Cefazolin, or Clindamycin

Mild = Oral Rx of PCN VK or Cephalosporin or Dicloxacillin or Clindamycin

Dicloxacillin = PCN stable in beta-lactamase

Clindamycin = most common abx assoc. w/ c-diff; take with probiotic

44
Q

Purulent skin infection

A

Furuncle/Carbuncle/Abscess

Mild = I & D

Moderate = I & D and C & S

Empiric therapy with Bactrim, Doxy

Defined Rx

MRSA = Bactrim

MSSA = Dicloxacillin or Cephalexin

*Keflex = First gen $4

45
Q

Brown Recluse Spider Bite

A

“Red, white, and blue”

Central blistering with surrounding gray to purple discoloration at bite site

Surrounded by ring of blanched skin surrounded by large area of redness

46
Q

Most common cause of new onset ulcerating skin lesion across North America

A

MRSA

47
Q

Nafcillin

A

Narrow spectrum

Beta-lactamase resistant PCN

Use of not risk factors for MRSA

48
Q

Rocky mountain spotted fever

s/sx and dx

A

Tick-borne

Most cases occur in spring or early summer

Early in disease: fever, malaise, arthralgias, headache, nausea w/ or w/o vomiting; children might present w/ abd pain

Rash between day 3 and 5 of illness

Early disease = empiric tx based on clinical judgment and epidemiological likelihood

Later disease = dx via skin bx or serological testing

49
Q

Rocky mountain spotted fever

Tx

A

Start within 5 days of symptom onset

Doxycycline 200 mg/day in two divided doses

Tx should continue until 3 days of patient being afebrile

Doxy: risk of dental staining in children

Doxy typically tolerated well except for N&V, give antiemetics/antimotility agents as needed

Doxy assoc. w/ photosensitivity = counsel about skin protection

Pregnancy: use chloramphenicol if available

50
Q

Lyme disease

A

Erythema migrans (central erythema, ring remains flat, blanches, does not desquamate)

Tx:

Doxy 100 mg BID x 10-21 days

Amox 500 mg every 6-8 hours for 21 to 30 days

Cefuroxime 500 mg BID x 20 days

Use Amox/Ceftin for children

Prophylaxis:

Within 72 hours of tick removal: Doxy 200 mg x 1 dose

51
Q

CA-MRSA tx

A

Bactrim DS = 2 tablets x 5-10 days

Rifampin can be added - use w/ caution CYP450 inducer

If can’t have sulfa (bactrim), use:

Doxy

Minocycline

To cover staph and strep use Bactrim with a beta-lactam (cephalosporin)

52
Q

Babies

A

Avoid sun exposure

Lightweight long pants, long-sleeved shirts, brimmed hats

May apply sunscreen 15 spf or > minimal amt

If sunburned - apply cold compresses to affected area

53
Q

Sun safety

Children > 6 months and adults

A

Hat w/ 3 inch brim or bill facing forward

Sunglasses that block 99 to 100% of UV, cotton clothing w/ tight weave

Stay in shade

limit sun exposure during peak intensity hours 10 and 4

Use SPF 15 or > on both sunny and cloudy days

Protect against UVB and UVA rays

Apply enough sunscreen 1 oz (30 mL) per sitting for older child and adult

Reapply every 2 hours or after swimming/sweating

Extra caution near water, sand, snow (reflects UV rays)

54
Q

Topical medication

amount:

for hands, face, anogential region

one arm, anterior or posterior trunk

one leg

entire body

A

2 g

3 g

6 g

30-60 g

55
Q

Topical medication Absorption

Which parts of the body have the greatest absorption?

What parts of the body have the least absorption

Relationship between medication viscosity and absorption?

A

face, axillae, genitals

palms and hands and soles of the feet

cutaneous absorption is inversely proportion to the thickness of the stratum corneum

Thicker/more viscous = greater absorption

56
Q

Topical Corticosteroids

Uses

potency determined by?

techniques to enhance delivery/potency?

Examples of low potency (class 5-7)

midrange potency (3-4)

high potency (2)

super-high potency (1)

A

inflammatory and allergy derm disorders

potency is based on vasoconstrictive effects

techniques to enhance delivery/potency?

cover with an occlusive dressing.

low potency (class 5-7):

  • hydrocortizone (all strengths and types)
  • triamcinolone
  • fluocinolone 0.01%; 0.025%

midrange potency (3-4)

  • betamethasone
  • mometasone

high potency (2)

  • fluocinolone 0.2%
  • fluocinonide 0.05%
  • betamethasone 0.05%

super-high potency (1)

  • Clobetasol
  • halobetasol
57
Q

Antihistamines

MOA?

Symptoms controlled?

Compare 1st and 2nd generation antihistamines

Examples of 1st gen

Examples of 2nd gen

A

MOA: Blocking histamine-1 receptor site (antagonist) in the respiratory tract, blood vessels & GI smooth muscle

Symptoms controlled: itching and allergy (runny nose) also antiemetic.

SE: anticholinergic and sedation (mainly 1st gen)

Compare 1st & 2nd gen antihistamines: 1st gen crosses the blood-brain barrier - more sedation and cognitive effects.

Examples of 1st gen

  • diphenhydramine – Benedryl
  • chlorpheniramine – Chlortrimetron (cranky cousin)

Examples of 2nd gen

  • loratadine – Claritin
  • desloratadine – Clarinex
  • cetirizine – Zyrtec
  • fexofenadine. – Allegra
  • levocetirizine – Xyzal