Fitzgerald - Dermatology Flashcards
Derm assessment questions
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?
Primary Lesions vs Secondary
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
Auspitz sign
Psoriasis
Pinpoint bleeding when scale is scraped off.
Vitiligo
Autoimmune against melanocytes
Common w/ other autoimmune diseases (thyroid)
Palpable Purpura
NEVER BENIGN
“blueberry muffin” appearance
e.g. Meninigitis rash
Macule
flat, nonpalpable discoloration
e.g.
Freckle
Papule
Solid elevation
e.g.
raised nevus
Umbilicated and example
Papule with indented center
e.g.
Molluscum contagiosum
Pustule
Vesicle-like lesion with purulent content
e.g.
Impetigo
Patch and example
> 1 cm
flat, nonpalpable discoloration
e.g.
Vitiligo
Plaque
> 1 cm
Raised lesion, same or different color of surrounding skin, can result from coalescence of papules
e.g.
Psoriasis
Bulla
> 1 cm
Fluid filled (bigger than vesicle)
e.g.
Necrotizing fasciitis
Cyst
Any size
Raised, enxapsulated, fluid-filled lesion
Always benign
e.g.
Intradermal cyst
Wheal
Any sized
Circumscribed area of skin edema
e.g.
Hives
Purpura
Purpura > 1 cm
Petechiae
Flat red-purple discoloration caused by RBCs lodged in the skin
Do NOT blanch
(vascular lesion = blanches)
Excoriation
Linear, raised, often covered with crust.
e.g.
scratch marks over pruritic areas
Crust
Raised lesions produced by dried serum and blood remnants
e.g.
scab
Lichenification
Skin thickening usually found over pruritic or friction areas
e.g.
Callus
Scales
Raised superficial lesiosn that flake with ease
e.g.
Dandruff
Erosion
Loss of epidermis
e.g.
area under vesicle
Ulcer
Loss of epidermis AND dermis
e.g
arterial ulcer
Chancre
Fissure
Narrow linear crack into epidermis, exposing dermis
e.g.
athletes foot
Annular lesion
In a RING
e.g.
Erythema migrans (“bull’s eye”) in Lyme disease
Scattered lesion
Generalized over body w/o specific pattern or distribution
e.g.
maculopapular rash in rubella
Confluent/coalescent lesions
Multiple lesions bleding together
Clustered lesions
Occurring ina group with pattern
e.g.
Acne-form drug induced rash
seen with lithium, phenytoin, and iodine use = anticipated adverse effect
Linear lesions
In streaks
e.g.
Contact dermatitis poison ivy
Reticular lesions
Appearing in a net-like cluster
e.g.
Erythema infectiosum (Fifth Disease/slapped cheek)
Dermatomal or zosteriform lesion
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
Varicella
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
Zoster (shingles)
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
Actinic Keratoses (AK)
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
Basal cell carcinoma
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
Squamous cell carcinoma
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
ABCDE
Malignant Melanoma
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
Psoriasis vulgaris tx
medium-potency topical corticosteroid
Rosacea tx
Topical metronidazole
Pityriasis rosea
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
Acanthosis nigricans
cutaneous manifestation of hyperinsulinemia
puberty = worsenign insulin resistance
can regress w/ control of disease
e.g. after gastric bypass
Erysipelas
Infection of upper dermis, superficial lymphatics
Streptococcus pyogenes (aka GABHS)
Cellulitis
Infection of dermis and subcutaneous fat
Streptococcus pyogenes, less commonly MSSA beta-lactamase producing, MRSA (resistance via altered protein-binding sites)
Cutaneous abscess, furuncle
Skin infection involving hair follicle and surrounding tissue
Carbuncles = cluster of furuncles connected subcutaneously, causing deeper suppuration and scarring
Staph aureus (MSSA, MRSA)
Nonpurulent skin infection
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
Purulent skin infection
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
Brown Recluse Spider Bite
“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
Most common cause of new onset ulcerating skin lesion across North America
MRSA
Nafcillin
Narrow spectrum
Beta-lactamase resistant PCN
Use of not risk factors for MRSA
Rocky mountain spotted fever
s/sx and dx
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
Rocky mountain spotted fever
Tx
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
Lyme disease
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
CA-MRSA tx
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)
Babies
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
Sun safety
Children > 6 months and adults
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)
Topical medication
amount:
for hands, face, anogential region
one arm, anterior or posterior trunk
one leg
entire body
2 g
3 g
6 g
30-60 g
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?
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
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)
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
Antihistamines
MOA?
Symptoms controlled?
Compare 1st and 2nd generation antihistamines
Examples of 1st gen
Examples of 2nd gen
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
