107. Dermatology Flashcards
Epidermis: what is this layer and what is in it?
stratified squamous
keratinocytes rpgoressing basal to superficial layer
5 layers of epidermis
stratum basele
spinosum
granulosum
lucidum
corneum (superf)
Epidermis also includes L___ cells and m___
langerhans
melanocytes
Does epidermis have direct blood supply?
no
gets nutrients by diffusion through dermal epidermal junction
What important features does the dermis consistent of?
ct
blood vessels
lymphatic vessels
n endings
immune cells
Subcutaneous layer components
ct
adipose tissue
Physiologic functions of skin
- barrier
- homeostasis of temp
- absorption of UV rays and production of vitamin D
- sendation
- immunologic
Key hx factors in derm questions
onset
duration
exposure to allergens
changes
progression/regression
pain/itch/fever/sex hx/occupation/hobbies
pmhx
What are 5 main categories of rash
- Malignancy
- Immune
- Vaculitic
- Allergic
- Infectious
Nicholsky sign +
gentle rub of skin = slough of epidermis
Primary vs secondary lesions
primary - disease itself
secondary - factors like scratching, treatment, healing, complicating infection
When might tests be a good idea for rash? (general nonsevere illness)
- secondary syphilis
- mono (monospot)
- Throat swab (rapid) and Culture for GAS
-KOH prep
-gram stain - ESR
-bx
For pt with severe systemic illness, blood tests to do?
severe systemic illness
cbc
blood cultures
Macule
flat circumscribed pigmented area <0.5cm in diameter
Patch
flat circumscribed pigmented >0.5cm in diameter
Papule
elevated solid palpable lesion, variable color <.5cm in diameter
Plaque
elevated solid palpable lesion, variable color >0.5cm in diameter
Nodule
solid, palpable, subcutaneous lesion <0.5cm in diameter
Abscess
erythematous, fluctant, tneder fluid filled nodule of any size
tumor
solid palpable subcutaneous lesion >0.5cm in size (basically big nodule)
Vesicle
elevated thin walled, circumscribed clear fluid filled lesion <0.5cm in diameter
Bulla
elevated thin walled, circumscibed lesion >0.5cm in diameter
Pustule
elevated circumscribed, puruplent fluid filled lesion of any size
Petechiae
flat erythematous or violaceous nonblanching lesions <0.5cm in daimeter
Purpura
flat erythematous or violaceous nonblanching lesions, may be palpable <0.5cm in diameter
Scale
thickened area of keratinized epithelium
Crust
dried area of plasma pro resulting from inflamm
fissures
deep crackes in skin surface extending into dermis
Erosions
disruption of surface epithelium, usually linear, traumatic
Ulcer
deep erosion extending into dermis
Scar
dense collection of collagen a result of healing after trauma or procedures
Excoriation
linear erosions typically secondary to scratching or rubbing
infections
bacterial viral fungal or protozoal causing breaks in dermal-epidermal junction often erythematous
Hyperpigmentation
incr in melanin containing epidermal cells
lichenification
abnormally dense layer of keratinized epidermal cells
Atopic dermatitis infantile and atopic eczema adult areas affected?
face scalp flexor surface of extremities
Dermatomyositis area affected?
dorsal mcp joint
periorbital area
disseminated gonorrhea area effeced
distal extremities, near joints
erythema nodosum: where present?
anterior shins, ulnar surfaces
Herpes zoster where present?
dermatomal distribution, particularly trunk
Lichen planus: where present?
wrists
ankles
flexor surfaces
Nummular eczema where present?
distal extremities
Neurotic excoriations
extremities
face
upper back
neck
Pityriasis rosea where present?
trunk
extremities
in xmas tree pattern
Prophyria cutanea tarda where present?
sun exposed areas, hands, forearms, feet
Psoriasis where present?
extensor surfaces of extremities
sacral area
Sarcoidosis where present?
face
extremities
back
sebhorrheic dermatitis where present?
chest
nasolabial folds
secondary syphilis where present?
torso
palms
soles
SLE where present?
nose and cheeks
head and neck
photosens
alopecia
tinea versiciolor where present?
upper back and chest
Impetigo: 2 pain bugs
staph aureus
GAS
Impetigo: typical lesion description
single pustule and later to multiple lesions, often with golden yellow crust
Impetigo: itchy or painful?
itchy
What is a complication of strep impetigo?
postpyodermal acute GN
Staph vs strep Impetigo: differences?
staph is more superficial with less surrounding erythema
Impetigo: ddx
hsv
inflammatory fungal infections
Bullous Impetigo: caused by toxin of what bug?
staph
Bullous impetigo: initial skin lesion/presentation of lesions?
thin walled
1-2cm bullae
rupture leaving thin serous crust and collarette like remnant
face/neck/extremities often affected
Bullous impetigo: ddx
contact dermatitis
HSV infection
superficial fungal infections
pemphigus vulgaris
Impetigo: abx tx if mild?
bacitracin or mupirocin
Impetigo: abx tx if more severe (not MRSA)?
oral abx
docloxacillin or cephalexin
Impetigo: abx tx if more severe (MRSA)?
doxy
clinadmycin
septra
Tx of bullous impetigo:
dicloxacillin or erythromycin or azithromycin
Even without tx, impetigo usually resolves within…
3-6 weeks
Folliculitis defn
inflamm of hair follicle
Folliculitis appearance
pustules with central hair in sites such as buttocks, thigh, beard or scalp
Folliculitis: itchy or painful
mild pain
Folliculitis ddx
acne
keratosis pilaris
fungal infection
What kind of folliculitis can occur after hot tub use or swimming pools, or in inds on antibiotics for acne?
gram negative pseudomonas
Folliculitis treatment local
antiseptic cleanser to area like povidone-iodine/chlorhexadine
Folliculitis treatment - extensive
antiseptic cleanser to area like povidone-iodine/chlorhexadine
and
doxy or dicloxacillin
Cellulitis: defn
localized erythema, swelling and pain of ST
Erysipelas: defn
strep infection of skin and subcut tissue, typically erythematous appearance with well demarcated border
often fever malaise and myalgias
___ may be a useful tool to differentiate a cellulitis from a abscess
ultrasound
Mild case of cellulitis: tx
cephalosporin or dicloxacillin or clinda
IV abx for treatment of cellulitis?
penicillin
ceftr
cefazolin
clindamycin
severe = piptazo
Abscess defn
accumulation of pus within body tissues
What is a furuncle?
skin abscess caused by staph infection involving hair follicles and surrounding tissue
Abscess: findings?
localized soft tissue swelling erythema and fluctuance
What will you see that is consistent with abscess on ultrasound?
fluid filled cavity from cellulitis: cobblestoning with fine reticular (net like) areas of hypoechoic stranding
Carbuncles: defn
large abscess that develop in the thick, inelastic skin on back of neck, back or thights involving multiple hair follices
can cause sepsis!!
Abscess treatment - mild?
I+D + septra or clinda
Mod and severe abscesses - treatment?
I+D
culture and sn
IV abx - vanco, dapto, linezolid
Hidradentitis suppurativa - defn?
sweat gland current abscess formation in axilla, groin resembling a furuncle
Hidradentitis suppurativa - when to tx?
fluctuant, painful and large for drainage
topical clinda for 3mo or if severe: oral cinda with rifampin 3-6mo +/- antiandrogen therapy if cont
recurrent - surgical management
Oral agents effective against MRSA
septra
doxy
clindamycin
minocycline
IV agents effective against MRSA
meropenem/ertapenem
clinda
linezolid
dapto
vanco
Ertyhema migans: cause?
Borelia burgdorferi from lyme disease
Erythema migrans: clinical stages - how many?
3
Lyme disease: stage I
early
malaise, headache, fever, LN incr, arthalgias
60-80% erythema migrans
Lyme disease: stage 1 resolves within?
4 weeks
Erythema migrans: what does this look like?
erythematous annular nonscaling lesion with a central clearing
Lyme disease: stage II
secondary annular lesion
fever
LN incr
neuro maingestations
cardiac conduction abn
last weeks to months
Lyme disease: stage III
chronic arthritis
dermatitis
CNS disease
Lyme disease: diagnostic tests
elevated ESR
serologic tests - two tiered system of ELISA and reflexive immuno blotting
Lyme disease: management
doxy or amox for 10-21d
Lyme disease: abx options
doxy
amox
clarithromycin
cefuroxime
erythromycin
azithromycin
Necrotizing fasciitis: what is this?
polymicrobial or monomicrobial (GAS, CA-MRSA) severe toxicity infection
Necrotizing fasciitis: radiographic test findings?
air
Necrotizing fasciitis: abx?
pip tazo or carbapenem
with vanco or linezolid
with clinda to kill active toxin first!!
Cutaneous findings with meningococcal infection?
macules
papules
vesicles
petechiae and purpura
10% of pt may present with Waterhouse-Friderichsen syndrome: what is this?
meningits AND shock with intracutaneous hemorrhage
Scarlet fever: bug cause?
GAS
Scarlet fever: distinct rash?
begins on chest - rough sandpaper like texure due to multitude of tiny papules
spreads rapidly within 24 hours
circumoral pallor
+ may have erythamtous lesions on palate of pharynx
in 10% of scarlet fever cases what kind of annular, erythematous lesions may you see that transient and reappear over days, weeks or months?
erythema marginatum
Treatment of scarlet fever and sandpaper rash?
oral pen VK 250mg PO BID or TID x 10d
adol-adults QID dosing orb 500mg BID x10d
or IM benzathine penivillin 600 000 units if <27kg vs >/= 1.2 millon units 1x dose
Scalet fever pt allergic to penicillin, treatment ?
erythromycin
macrolide
cephalosporin
Syphilis primary lesion
chancre singel or multiple at site of inoculation
papule –:> ulcer approx 1c diameter with central base and raised borders
PAINLESS unless secondary infection
has PAINLESS lymphadenopathy
Secondary syphilis lesions
erythematous or pink maucles or papules in a symmetric distribution
pigmented macules/papules on palms and soles
moist/flat/verrucous condyloma lata in genital area
Primary and secondary syphilis, early latent treatment
benzathine pen B 2.4 milion units IM
vs doxy and azithro if ++ allergic
Late latent and tertiary tx of syphilis?
benzathine pen B 3 x 2.4 million units IM at weekly intervals for a total of 7.2 million units
Jarisch Herxheimer reaction
symtpoms of fever, headache and malaise after tx of syphilis
Disseminated gonococcal infection: lesions
periarticular regions of distal extremities starting as erythematous or hemorrhagic papules, into pustules and vesicles with erythematous halo
tender
gray necrotic or hemorrhagic centre
crusty after 4-5 days
Disseminated gonococcal infection: tx
culture from wound
ceftr 1g IVq24h
Staphylococcal scalded skin syndrome (SSSS): typically occurs in children of what age?
</=6
Staphylococcal scalded skin syndrome (SSSS): what is it caused by?
exotoxin producing staphylococci
Staphylococcal scalded skin syndrome (SSSS): illness begins with what findings?
progression of findings?
erythema and crusting around mouth
then spreads down body, followed by bulla formation and desquamation
desquamation
lesions dry up and clinically resolve 3-7d
Staphylococcal scalded skin syndrome (SSSS): what is typically spared?
mucous membranes
Staphylococcal scalded skin syndrome (SSSS): treatment
vancomycin
nafcillin
oxacillin
vs allergy: clarithromycin or cefuroxime
Toxic shock syndrome: what is this?
acute febrile illness characterized by diffuse desquamating erythroderma
fever, hypotension, constitutional symptoms and multiorgan involvement
Toxic shock syndrome (TSS): bug?
exotoxin producing staph aureus
or GAS
Toxic shock syndrome (TSS): causes
mentruation/tampon use
burns/post op
postpartum
OM
arthritis
empyema
fasciitis
septic abortion
pharyngitis
peritonsillar abscess
sinusitis
subcutaneous abscess
Toxic shock syndrome (TSS): diagnosis requires which 4 criteria?
- temp of at least 38.9
- hypotension (SBP 90 or less)
- rash
- involvement of at least 3 organ systems
Toxic shock syndrome (TSS): typical rash?
diffuse
blanching
macular erythroderma
nonexudative mucous membrane involvement is common
Toxic shock syndrome (TSS): when does rash fade?
within 3d
Toxic shock syndrome (TSS): once rash fades, where does desquamation occur?
hands and feet
Toxic shock syndrome (TSS): initial treatment
IV fluid
ventilatory support
pressors PRN
abx - clinda, vanco, linezolid, imipenem, mero, pip tazo are all options
Rocky Mountain spotted fever: bug?
ricketsia rickettsii
by tick saliva
Rocky Mountain spotted fever: onset of illness abrupt with what sx?
headache
n/v
myalgias
chills
fever
Rocky Mountain spotted fever: may last 3 weeks: what are the predominant organ systems involved?
cns
cardiac
pulmonary
GI
renal
DIC
shock
Rocky Mountain spotted fever: when does a rash develop (ie what day?)
2-6th day
Rocky Mountain spotted fever: rash appearance?
erythematous macules that blanch on pressure
first seen on wrist and ankles
then up extremities to trunk and face which becomes petechial or hemorrhagic
*have lesions on palms and soles
Rocky Mountain spotted fever: dx typically?
clinical
Rocky Mountain spotted fever: tx?
doxy
children <9 - chloramphenicol
Rocky Mountain spotted fever: what abx makes this worse?
sulfa drugs
Rocky Mountain spotted fever: what disease looks similar to this but is also treated with doxycylcine?
ehrlichiosis
HSV characteristics of lesions
painful grouped vesicles on an erythematous base
clustered, nondermatomal region
MC HSV1 area?
mouth
HSV: what is this called when on hand?
herpetic whitlow - distal phalanx typically
HSV: 1 typically heals within how many days (unless bacterial infection)
7-14d
HSV: 2 - presentation in men
either single or multiple vesicles or erosions on penile sahft/glans
+ regional adenopathy, fever, malaise