126 Skin and soft tissue infection Flashcards
What important cells live in the epidermis?
keratinocyte
langerhands cell
melanocytes
sweat glands
Disruption of the dermis results in what skin changes?
vesicles
bullae
What important cells are in the subcutaneous tissue
lymphatic drainage
Linear erythema tracking along vascular pathway ddx 2
phlebitis
lymphangitis
Pruritic snakelike lesions not particular tender ddx?
parasite - scabies, hookeworm, stronglyoides
What are janeway lesions?
painless red purple or brown spots on hands or feet from septic embolic from IE
Painless discoloration of the palsm and soles ddx 2 important?
secondary syphilis
RMSfever
DDX petechiae and purpura
sepsis
mengingococcemia
kawasaki
gpa
What is cellulitis?
inflamm cond of skin and subcut tissue caused by bacteria
Cardinal feature of cellulits?
inflamm with incr local blood flow
Cellulitis with signs of lymphangitis - commonly seen in what bug?
pasteurella multocida
Erysipelas is often caused by ?
GAS
MC bugs in acute diabetic foot infections?
S aureus
Streptococci
Human bite mc infection?
polymicrobial - eikenella, fusobacterium, GAS, S aureus
Cat bite common bug concern?
pasteurella
When do even dog bites need prophylactic abx?
face
hands
genitals
areas of poor perfusion
immunocomp pt
First line treatment and bug: uncomplicated abscess
MRSA
I+D, abx
First line treatment and bug: nonpurulent bacterial skin infection
strep, staph aureus
keflex or clinda, adjuncts
First line treatment and bug: purulent cellulitis and wound infections
mrsa, strep
septra, doxy
First line treatment and bug: DFU
mixed gram neg pos and anaerobes
amox clav and septra
First line treatment and bug: cat bite or infected dog bite?
amox clav
pasteurella
First line treatment and bug: human bite
oral anaerobes etc
amox clav
First line treatment and bug: erythema migranes
borrelia burgdoferi
doxy
First line treatment and bug: puncture would through sole of shoe
pseudmonas
levo
First line treatment and bug: buccal cellulitis
hinlfu
ceftr or amp sulbactam
First line treatment and bug: balantis
candida albicans or GAS
fluconazole and pen/amox + test for db
First line treatment and bug: Liposuction
peptostreptococcus, gas
amp-clav acid and septra
First line treatment and bug: saltwater exposure
vibrio vulnificus
doxy
First line treatment and bug: freshwater
aeromonas sp
ciprofloxacin
First line treatment and bug: butcher, clam handler or vet
erysipelothrix rhusiopathiae
amoxicillin
First line treatment and bug: black necrotic eschar with rasied border and severe edema?
bacillus anthracis (anthrax)
cipro
Who is particularly at risk from vibrio of salt water?
liver disease pt
Pseudocellulitis ddx
venous stasis derm
burns
viral infection
fixed drug eruption
lymphedema
VTE
gout
contact dermatitis
ALT-70 to differentiate cellulits from pseudo - what does this entail?
Asymm
Leukocytosis
tachycardia
age >/=70
If necrotizing infection is thought ,what imaging can be helpful?
ct
but should really call prs/service in charge
How long to tx bites for?
3-5d
Bite infection - pen allergic (severe) alternative?
clinadymin
What is an abscess?
bacteria multiplication below the epidermis
Carbuncle defn
multiple furuncles with loculation and connecting sinus, often mult sites of drainage
Furuncle defn
Boil - abscess of the hair follicle
Carbuncle place mc and disease RF?
neck
diabetes
Bartholin gland cyst - what to test for?
STBBI
Pilonidal abscess - where is this?
superior aspect of gluteal cleft between buttocks
–> surgical excision referral by surg
Concerning signs for necrotizing fasc?
- systemic toxicity - pain out of proportion, abnormal vitals, AMS
- crepitance
- skip lesions/radid progression
- hemorrhage, sloughing, blisterin
Ultrasound findings of an abscess
hypoechoic areas with posterior acoustic enhancement
Oral options for MRSA
clinda
septra
doxy
linezolid
What is an epidermoid cyst?
benign cystic tymor for accumulation of kertainecous material
-can be painful, rupt spontaneously
-can tx abx and nsaid
How to I+D an abscess?
analgesia
incise
blunt dissect
irrigate
pack
How to tx a Bartholin Abscess?
small incision around 3mm on site, cavity drained
word catheter insertion and inflated with 4ml of saline
leave in place 4-6 weeks so sinus tract can form
sitz bath
When to consider other tx for a barhtolin gland cyst?
marsupialization if recurrent (but no usually acute)
Abx post abscess?
simple, no risk mrsa - risk/benefit discussion with pt
abx if limited f/u, assocv cellulitis, mult infection sites, systemic illness, assoc comribdities and immunosuppression, extreme of age, abscess in area difficult to drain (hands, genitalia, feet), septic phlebitis, poor response to I+D alone
Impetigo two forms?
bullous and non
What does impetigo look like?
thin walled vesicles progressing to pustules, honey crusted lesions on face or extremity
often have lymphadenopathy
Bullous impetigo bug
S aureus, MRSA
toxin procudes bullae from dermal epidermal junction release (0.5-3cm)
Deep impetigo - what does this look like?
ulcers, punched out appearance, rasied red margins covered. with thick crust
typically LE
Nonbullous impetigo tx
topical mupirocin
multiple lesions/extensive tx with MRSA
Bullous impetigo tx
abx against MRSA and strep
keflex + septra
Folliculitis defn
superficial inflamm of hair follicle limited to epidermis
What does folliculitis look like?
small 2-5mm raised erythematous, painful, tender lesions typically itchy
ex beard, hot tub
Folliculitis tx
if regular - topical mupirocin, avoid trigger
if candida concern (immunocomp) - tx antifungals, r/o immunocomp
hot tub (pseudomonas)- cproflox and antihist
Hidraenitis suppurativa - what is this?
acne inversa - painful usually in axilla or inner area
aceniform disorder with follicular occlusion rather than infection of sweat glands
Hidradenitits suppurativa tx
incision of painful nondraining lesions for sx release
systemic abx for symptomatic lesions and should cover mrsa
LT immunomod, hormones and en bloc resection (derm vs PRS)
pain control key
RF nec fasc
db
vascular insuff
immunosuppression
penetrat taruma
recent surg
varicella inection
IVDU
burns
childbirth
What bugs cause nec fasc?
MC poly:
GAS
s aureus
enterococci
enterobacteriaceae
anaerobes: bacteriodes, clostridium
2 types of nec fasc
1: polymicrobial: aerobe and anaerobes
2. single organism: GAS, MRSA
“Gas gangrene” - medical term
clostridial myonecrosis
MC cause of traumatic myosistis/myonecrosis?
clos perfringins
exotoxins causing shock –> IV hemolysis + DIC
Anaerobic streptococcal myositis: bug? general course?
peptostreptococus, or GAS or S aureus
insidious but still resembles clostridial myonecrosis
Pyomyositis defn
deep abscess within striated m resulting from hematogenous spread of bacteria in setting of m injury
-S Aureus
Phlegmasia cerulea dolens - what is this?
iliofemoralvein thrombosis - may look like nec fasc
Nec fasc tx
clinda
pip tazo
vanco
surg asap
3 main types of toxic shock syndromes
-staph
-strep
-staphyloccla scalded skin syndrome
Stretococcal toxic shock syndrome: can occur in ?
prior healthy people
Invasive GAS: how do toxins work?
exotoxin A and B act as superAg and cause overactivation of T cells with massive release CK
- flu likefirst, then septic shock
GAS toxic shock syndrome: complications
DIC
renal failure
ARDS
Streptococcal TSS: organism and toxin
GAS, pyogenic exotoxion
Streptococcal TSS: source
nec infection
Streptococcal TSS: rash
erythematous rash only in 10%
oftne have signs of nec infection and exfoliation weeks later
Streptococcal TSS: mortality %
30-80
Streptococcal TSS: tx
resus
op debridement
Staph TSS: toxin and organism
tss type 1: enterotoxin A, B, C
staph aureus
Staph TSS: pt type
prior healthy
Staph TSS: source
nasal wound or packing
tampon
infection may also not be clear
Staph TSS: rash
initially diffuse erythroderma exfoliation after 1-2wk, mucosal hyperemia
Staph TSS: systemic illness findings compared to strep
similar: hypotension, shock: multiorgan failure more likely in GAS > staph
Staph TSS: tx
resus
Staph ScaledSS: bug and toxin?
staph aureus
epidermolytic toxin A or B
Staph ScaledSS: pt?
infant
Staph ScaledSS: source
skin flora
Staph ScaledSS: rash
tender erythematous rash
localized blister
extensive exfoliation if have no abx to toxin
mucosa spread
Staph ScaledSS: sx
fever, irritability ( as particularly infant)
Staph ScaledSS: mortality
<5%
Staph ScaledSS: tx
wound care
hydration
Staph TSS: mortality %
<5
What toxin is most associated with Staph TSS in menstrual causes?
TSST-1
SSSS: where does toxin target?
act as proteases - target protein desmoglein 1 on stratum granulosum layer or epidemrus
Staph ScaledSS: nikolsky?
+
Trend of rash in RMS fever?
wrists and spreads everywhere including palsm and soles
macular –> petechial and then dusky
Anthrax rash presentation
incubation 1 week –> vesicle
ruptures leaing shallow based ulcer with raised border
painless necrosis and escar, surrounding edema
Tularemia: from?
exposure to rodents, rabbits hairs
Tularemia: skin presentation and other sx?
flu like
ulceroglandular form
lesion itself is raised vs border only in anthrax
Cutaneous leishmaniasis lesions:
face - painless, ulcerative, dysfiguring
papules - wory about myiasis botfly!
What type of skin rash in kids can lead to PSGN?
impetigo
How to treat eosinoophilic folliculitis?
isotretinoin
SSSS - key: spares what?
mucous membranes
