skin conditions Flashcards
risk factors for melanoma
> 65 yo
fair-skinned
many atypical moles
50 moles
if diagnosed with BCC
40% will be diagnosed with 2nd BCC in 3 years
history taking for skin condition
look at skin, feel (infectious: scabies, HSV, syphillis), distribution and then ask questions
scaly rash
precancerous lesion of seborrheic keratosis
actinic keratosis
scattered lesions (bloodborne) vs along sensory dermatome
chickenpox vs HSV
nail pitting
psoriasis
hand eruption: autosensitzation to
fungal infection on feet
white patches on buccal mucosa
lichen planus
hereditary skin conditions
psoriasis acne atopic dermatitis skin cancer dysplastic nevi neurofibromatosis tuberous sclerosis
fungal infection lab preparation
KOH slide: see hyphae of dermatophytes or psuedohyphae of yeast of candida or pityrosporum
diagnosis of tinea capitis
wood’s light: green fluourescence
-caused by microsporum
diagnosis of erythrasma
wood’s light: red fluorescence
medical treatment of skin conditions
topical steroids: antiinflammatory, anti-mitotic effect, SE: skin atrophy (reversible) - capillaries dilate, hypopigmentation, striae (irreversible), systemic SE: if young, thinner skin
PO steroids
antibiotics
antifungal/antiviral
diagnostic + surgical treatment of skin conditions
shave: raised
punch, ellipitcal: flat
scissor
choosing topical steroid
chronic disease: higher potency
thicker: higher potency (psoriatic plaque)
thin: face, GU, skin folds - low potency
infant/children: higher SA, increased absorption - low potency
type of vehicle of topical steroid affects
potency - determines rate at which steroid is absorbed
bacterial skin infections
s. aureus - most common MSSA abx: cephalexin, dicloxacillin, clindamycin MRSA abx: trimethorpim-sulfamethoaxazole (bactrim) rifampin clindamycin tetracycline
honey crusts around nose + mouth
impetigo
impetigo tx
s. aureus, MRSA (bullous impetigo) and s. pyogenes:
7-10 days Abx:
cephalexin
dicloxacillin
severe variation of bullous impetigo
bullae caused by exfoliating toxin
systemically ill
SSSS:
IV Abx, fluids
infection of dermis + subq tissues
- break in skin from trauma, bite, dermatosis (tinea pedis)
- usually extremities
cellulitis
cellulitis tx
B hemolytic strep or s. aureus
need MRSA coverage (IV or PO)
infection of dermis with lymphatic involvement - usually extremities (lesions raised above skin, clear demarcation)
erysipelas
erysipelas
B hemolytic strep
need MRSA coverage(IV or PO)
infection of superficial portion of hair follicle
perifollicular erythema, papules, pustules
S. aureus, yeast, other bacteria
hot tub folliculitis
psuedomonas
folliculitis with tight fitting clothing
pityrosporum yeast
abscess that starts in hair follicle or sweat gland
furuncle or boil
furuncle extends into subq tissue
carbuncle
cause of skin abscess
s. aureas, MRSA
I&D, po antibiotics if surrounding cellulitis
infection of subq tissue + fascia diffuse swelling → bullae skin necrosis/echymosis (bruising) edema beyond area of erythema pain out of proportion systemic: fever, tachycardia, delerium, renal failure, rapid spread during antibiotic therapy
necrotizing fasciitis
treatment of NF
s. pyogenes: after VZV, scratch, insect bite
bowel flora
need surgical debridement + IV abx
cause of warts
HPV
hands: verruca vulgaris
feet: plantar warts
face/legs: flat warts
cauliflower appearance
transmitted sexually
genital warts - HPV 6 (condyloma acuminata)
causes cervical intraepithelial neoplasia and cervical cancer and throat cancer
HPV 16, 18
virus in dorsal root ganglia - recurrence
vesicular, surrounding erythema, crusts over weeks
HSV and VZV
primary herpes gingivostomatitis (cold sore) and labialis (lips)
primary: whole mouth, fever, chills, maliase
recurrent episodes are labialis (lips): viral shedding, asymptomatic
herpetic lesion on but, genital, anus
HSV
HSV can be spread when asymptomatic (between active episodes)
can shed virus asymptomatically
if active ulcer + HIV +
more likely to acquire HIV
vesicles on red base
trunk → extremities
fever + respiratory symptoms
initial infection of VZV (chickenpox)
complications of HSV or VZV
encephalitis
disseminated infection
esp if infant or IC
postherpatic neuralgia: chronic pain in dermatome previously infected with herpes zoster (shingles)
HSV tx: acyclovir, famiciclovir, valacyclovir
prophylactic oral antiviral to prevent or reduce recurrences
VZV tx: acyclovir (only one approved for chickenpox), famiciclovir, valacyclovir
early antiviral to prevent postherpatic nueralgia
causes of fungal skin infections
dermatophytes: tinea infections (ringworm)
candida
pityrosporum
annular appearance with central clearing, redness, scale on perimeter
tinea corporis
inflammatory reaction to pityrosporum (malassezia furfur)
tinea versicolor
thrush
balanitis
vaginitis
rashes in groin, breast
candida
hair loss with broken hairs + scaling
tinea capitis: hair shaft + follicle involved
red, scaling
no central clearing
in groin
tinea cruris (vs candida infection: redder, satellite lesion vs erythasma: pink/brown, red flouresnce)
scaly, itchy, symmetric
hx or family hx of asthma, allergic rhinitis
infant: face → FLEXURAL: antecubital fossa, popliteal
atopic dermatitis
linear, vesicular
response to poision ivy, nickel, deodarants
allergic contact dermatitis
treatment of dermatitis/eczema
avoid skin irritants/hot water: dry skin
emollients: add moisture
topical steroid: inflammation
occurs in areas with most pilosebaceous units producing sebum inflammatory hypersensitivty to yeast: pityrosporum worsens with stress, cold erythema, scaling of scalp + face over sternum axillae umbilicus groin gluteal creaes
seborrhea
treatment of seborrhea: not curative
antifungal
topical steroid
epidermal proliferation and inflammation
well-demarcated red, scaling plaques
white thickened scales
EXTENSOR surface, sacral region, genitalia, scalp
nail changes: pitting, subungual keratosis
psoriasis
treatment of psoriasis
emollients
topical steroids - high potency (most common)
topical tar
types of BCC
nodular: pearly papules, telangiectasias, central ulcer - lesion bleeds or itchy, grows
superficial: red, pink,flat, scaling (like SCC)
sclerosing: scarlike
SCC
hyperkeratotic
scaly, ulcerate, bleed easily
irregular shaped plaques or nodules with raised borders
higher risk of metastasis vs BCC
actinic keratosis
bowen disease (SCC in situ)
HPV
are precursors to
SCC
ABCDs of malignant skin cancer
Assymetric Border Color Diameter: >6 mm Evolution (bleeding, enlarged), elevated (raised)
biopsy skin lesion if
think premalignant or malignant only
2-3 mm margin around lesion for complete excision
if pathology says malignant - need 5 mm margins
if lesion to large - ensure excision is full-thickness of most suspicious part
risk factors: UV radiation for all skin cancers (#1), family history or personal hx of skin cancer, fair skin, burn easily, chemical exposure, suppressed immune system
bulla
blister >0.5 cm
macule
not raised or depressed
nodule
elevated lesion
> 1 cm in diameter
papule
elevated lesion
vesicle
blister
plaque
plateu like, raised
most common type of melanoma in both sexes
raised, brown with pink, white, gray, blue
spreads along top before penetrating into deep layers (dermis and beyond)
radial growth slower than vertical phase
men: upper torso
women: legs
superficial spreading melanoma
most common in 60-70 yo
brown/tan with irregular borders
chronic sun-damaged skin: face, ear, arm, upper trunk
lentigo maligna
most common type in AA and asians
under nails, sole of foot, palm of hand
flat, irregular, brown/black
acral lentiginous melanoma
unique feature: invasive at time of diagnosis
most aggressive
brown/black
nodular melanoma
shave biopsy
raised lesion
punch biopsy/elliptical excision
flat lesions
prognostic feature of melanoma
thickness
treatment of localized reaction to bug bite (venom releases histamine-like substance):
red, warm, swollen
tender, itches
occur immediately, last few hours
no antibiotics
pain: NSAID or acetaminophen
antihistamine, ice: itching
Td booster if not up-to-date
immediately remove stinger by scraping or brushing stinger off (credit card preferred) because
causes continued injection of venom
treatment of LARGE local reaction (IgE mediated to venom) >10 cm diameter red, warm occurs over 24-48 hrs 50% risk of similar reaction in future NO increased risk of anaphylaxis
oral steroids initiated early after sting
Td booster if not-up-to-date
treatment of systemic anaphylaxis reaction to sting:
gradient: nausea, urticaria, angioedema to hypotension, shock, airway edema, death
occurs within minutes
50% risk of anaphylaxis with future stings
ABC
IV access
fluid resuscitation to 10-20 mg/kg asap
suq or IM epinephrine asap (repeat q 10-15 min PRN)
+/- antihistamines, steroids, bronchodilators
Td booster if not-up-to-date
hospitalized for 12-24 hrs since symptoms may reoccur
densensitization tx: can reduce risk by 50%
animal and human bite management
ABC
clean with soap + water, irrigate with saline, debride devitazlied tissue asap
vaccination status of animal: rabies (bat, skunk, dog, fox -NOT rodents/rabbits)
antibiotic prophylaxis
Td vaccine up-to-date
bite wounds with increased risk of infection
large, deep
hand
host chronic illness, immune suppression
cat or human bite
dog and cat bite organisms
staph
strep
anaerobes
pasteurella
human bite organisms
staph strep haemophilus eikenella: most common in closed fist injury anaerobes
closure of bite wounds
treatment of bite wounds
especially if on hand, late presentation, dog/cat/human bite
antibiotic prophylaxis for 5-7 days if mod-severe wound
amoxicillin-clavulanate (augmentin PO)
if cellulitis (erythema around site) also present: 7-14 days PO
hospitalization/surgery: osteomyleitis, joint infection
