Dermatology Flashcards
Treatment of CA-MRSA
Bactrim
Doxy/minocycline
Clindamycin (lower coverage on staph, but also covers strep)
Treatment of Group A strep skin infection
Bactrim PLUS beta lactam (PCN, amoxicillin, Keflex)
Doxy/minocycline PLUS beta lactam
or Clindamycin
Treatment for subungal hematoma
Trephination: drill a hole to release the pressure (heated instrument)
Tinea capitis
Selenium sulfide 2.5 percent shampoo
Oral for severe cases (terbinafine, itraconazole, griseofulvin- check LFTs!)
Tinea pedis, tinea manuum
topicals, aluminum subacetate soaks
Onychomycosis
oral antifungals (itraconazole, terbinafine)
Tinea versicolor
Selenium sulfide 2.5% shampoo, topical antifungals
Candida intertrigo, tinea corporis, candida balanitis, tinea cruris
Topical antifungals or oral for severe cases
Herpes Zoster (shingles)
Dermatomal distribution (doesn’t cross midline, unlike varicella)
Tx: acyclovir, famciclovir, valacyclovir; REFER if suspected ocular involvement
Tx post herpetic neuralgia: Gabapentin, pregabalin
Actinic keratosis
rough (dry, scab-like), flesh-colored, hyperpigmented
pre-malignant (to squamous cell carcinoma)
tx: liquid nitrogen
Squamous cell carcinoma (SCC)
arise out of actinic keratosis
firm, irregular papule or nodule under dry patch
prolonged sun exposed areas
Tx: biopsy, surgical excision (Mohs)
Seborrheic keratosis
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
Basal cell carcinoma
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
malignant melanoma
highest mortality rate
median age at diagnosis: 40
moles with: Asymmetry, Border irregularity, Color variation, Diameter >6mm, Elevation, Enlargement
Tx: biopsy and surgical excision
Eczema
Intense pruritis
red, shiny, thick patches; later dry leathery lichenification
topical steroids, rubbed in well
Allergic contact dermatitis
often LINEAR in nature
red, pruritis, scabbing, sharply defined borders
topical steroids
Psoriasis
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
Pityriasis rosea
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
Xanthelasma
yellow plaques as the result of fat buildup under the skin, usually near the inner canthus (hyperlipidemia is underlying cause)
Lyme disease
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)
Rocky Mountain Spotted Fever
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)
Small pox
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
Anthrax
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
Warts
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)
How do you treat frost bite?
Assess for hypothermia
Soak in water at 100F
Treat for pain
How do you treat insect bites?
remove stinger
topical steroids
topical anesthetics
Bacterial infections and their causative organisms: Folliculitis, Furuncle, Carbuncle, Cellulitis, Erisypelas, Hidradenitis suppurativa, impetigo, paronychia
Folliculitis, furuncle, and carbuncle: staph
Cellulitis: strep, staph is less likely
Erysipelas: strep
Hidradenitis, Impetigo, Paronychia: staph
