Dermatology

Question 1

Treatment of CA-MRSA

Answer 1

Bactrim
Doxy/minocycline
Clindamycin (lower coverage on staph, but also covers strep)

Question 2

Treatment of Group A strep skin infection

Answer 2

Bactrim PLUS beta lactam (PCN, amoxicillin, Keflex)
Doxy/minocycline PLUS beta lactam
or Clindamycin

Question 3

Treatment for subungal hematoma

Answer 3

Trephination: drill a hole to release the pressure (heated instrument)

Question 4

Tinea capitis

Answer 4

Selenium sulfide 2.5 percent shampoo

Oral for severe cases (terbinafine, itraconazole, griseofulvin- check LFTs!)

Question 5

Tinea pedis, tinea manuum

Answer 5

topicals, aluminum subacetate soaks

Question 6

Onychomycosis

Answer 6

oral antifungals (itraconazole, terbinafine)

Question 7

Tinea versicolor

Answer 7

Selenium sulfide 2.5% shampoo, topical antifungals

Question 8

Candida intertrigo, tinea corporis, candida balanitis, tinea cruris

Answer 8

Topical antifungals or oral for severe cases

Question 9

Herpes Zoster (shingles)

Answer 9

Dermatomal distribution (doesn’t cross midline, unlike varicella)
Tx: acyclovir, famciclovir, valacyclovir; REFER if suspected ocular involvement
Tx post herpetic neuralgia: Gabapentin, pregabalin

Question 10

Actinic keratosis

Answer 10

rough (dry, scab-like), flesh-colored, hyperpigmented
pre-malignant (to squamous cell carcinoma)
tx: liquid nitrogen

Question 11

Squamous cell carcinoma (SCC)

Answer 11

arise out of actinic keratosis
firm, irregular papule or nodule under dry patch
prolonged sun exposed areas
Tx: biopsy, surgical excision (Mohs)

Question 12

Seborrheic keratosis

Answer 12

benign, nonpainful
beige, brown, black plaque
"stuck on" appearance
(melanoma may hide in patches of these)
Tx: none, or liquid nitrogen, refer to derm for eval of multiple

Question 13

Basal cell carcinoma

Answer 13

most common skin cancer
"waxy, pearly" skiny red
volcano-like- edges cave in
"I pick it off and it keeps coming back"
Tx: refer to derm for biopsy/excision

Question 14

malignant melanoma

Answer 14

highest mortality rate
median age at diagnosis: 40
moles with: Asymmetry, Border irregularity, Color variation, Diameter >6mm, Elevation, Enlargement
Tx: biopsy and surgical excision

Question 15

Eczema

Answer 15

Intense pruritis
red, shiny, thick patches; later dry leathery lichenification
topical steroids, rubbed in well

Question 16

Allergic contact dermatitis

Answer 16

often LINEAR in nature
red, pruritis, scabbing, sharply defined borders
topical steroids

Question 17

Psoriasis

Answer 17

benign hyperproliferative inflammation of the skin (acute or chronic)
may present as first sign of HIV infection
itchy, red, “precisely defined plaques with silvery scales”
Auspitz’ sign
Tx: topicals for scalp (tar/salicyclic acid shampoo), topical steroids, UVB light exposure

Question 18

Pityriasis rosea

Answer 18

females > males, often in spring and fall
pruritis rash on trunk and proximal extremities
Initial lesion 2-10cm: herald patch, then generalized rash within 1-2 weeks (Christmas tree pattern)
Not contagious; rash lasts 4- 8 weeks
Tx: rule out syphilis!, oral antihistamines, topical antipruritic, topical steroids, UVB light, oral erythromycin

Question 19

Xanthelasma

Answer 19

yellow plaques as the result of fat buildup under the skin, usually near the inner canthus (hyperlipidemia is underlying cause)

Question 20

Lyme disease

Answer 20

24 to 48 hours of tick feeding to transmit Borrelia burgdorferi to host
Bull’s eye rash: erythema migrans in 50 percent of cases
Flu-like symptoms in 50 percent of cases
Dx: ELISA to screen, western blot to confirm
Tx: doxycycline, amoxicillin, Refer (report to health dept as well)

Question 21

Rocky Mountain Spotted Fever

Answer 21

tick bite, Rickettsiae
maculopapular or petechial rash, abdominal pain, joint pain, flu sx
Dx: PCR, immunohistochemical (IHC) staining, indirect immunofluorescence assay (IFA) with R. rickettsii antigen
Tx: doxycycline, refer (and report to health dept)

Question 22

Small pox

Answer 22

caused by virus; localizes in blood vessels of the skin, mouth, throat
S/sx: Sudden onset of flu-like symptoms; rash appears as flat red spots/lesions and within 2 days lesions turn into small blisters filled with fluid and later pus; scabs lead to deep pitted scars; Excruciating pain
Distribution of lesions is hallmark: first on oral mucosa/palate, then face or forearms; centrifugal distribution with greatest concentration on face and distal extremities
No cure once infected; supportive therapy; isolate person to prevent transmission

Question 23

Anthrax

Answer 23

bacteria Bacillus anthracis (often referred to as “spores” though)
Cutaneous: most common: exposed areas on arms and hands followed by face and neck; pruritic papule leading to ulcer surrounded by vesicles; develops into black necrotic central eschar with edema; leaves permanent scar
Inhaled: flu like symptoms, leading to fever, diaphoresis, and septic shock
Vaccine exists for those at risk; tx with PCN, cipro, doxy
not contagious

Question 24

Warts

Answer 24

common- flesh colored papule with rough surface
filiform- finger-like appearance with various projections
flat- pink or light yellow
plantar- rough surface, slightly raised, may be painful
genital- pale pink with several projections and broad base (cauliflower)

Question 25

How do you treat frost bite?

Answer 25

Assess for hypothermia
Soak in water at 100F
Treat for pain

Question 26

How do you treat insect bites?

Answer 26

remove stinger
topical steroids
topical anesthetics

Question 27

Bacterial infections and their causative organisms: Folliculitis, Furuncle, Carbuncle, Cellulitis, Erisypelas, Hidradenitis suppurativa, impetigo, paronychia

Answer 27

Folliculitis, furuncle, and carbuncle: staph
Cellulitis: strep, staph is less likely
Erysipelas: strep
Hidradenitis, Impetigo, Paronychia: staph