Skin and Soft Tissue Infections Part 1

Question 1

Skin and soft tissue infections are one of the most common infections where??

Answer 1

in BOTH the community and in hospital settings

Question 2

which layers of the skin may be involved in skin and soft tissue infections

Answer 2

may involve any or all layers

including epidermis, dermis, hypodermis, fascia, and muscle

Question 3

true or false

skin and soft tissue infections are not a big clinical concern because they stay localized

Answer 3

FALSE

they can spread and lead to more severe complications like endocarditis and gram negative sepsis

Question 4

the MAJORITY of skin and soft tissue infections are caused by what organisms (in general)

Answer 4

gram positive organisms that are on the skin

Question 5

differentiate between the normal flora ABOVE THE WAIST and the normal flora BELOW THE WAIST

Answer 5

above the waist - primarily gram positive - ie: coagulase negative staph, corynebacterum, MRSA, mssa, strep pyogenes

below the waist - all gram positive present above AND gram negative (enterobacterales, enterococcus)

Question 6

name 2 NOSOCOMIAL pathogens

Answer 6

pseudomonas aeruginosa
MRSA

Question 7

true or false

MRSA cannot be community-asssociated

Answer 7

FALSE

it can - there is community-associated MRSA (CA-MRSA)

Question 8

in general, what are risk factors for skin and soft tissue infections

Answer 8

anything that affects the skin integrity

for example – trauma, inflammation, obesity, breaks in skin, venous insufficiency, etc

Question 9

what are 2 broad categorizations of SSTIS

Answer 9

purulent (cause pus formation)
and nonpurulent (no pus formation)

Question 10

name 4 purulent skin and soft tissue infections

Answer 10

folliculitis
furuncle
carbuncle
ascess

Question 11

name 4 non-purulent SSTIS

Answer 11

impetigo
erysipelas
cellulitis
necrotizing fasciiitis

Question 12

typically, purulent skin and soft tissue infections are caused by which bacteria?

Answer 12

staph aureus

SO, must cover for MRSA in empiric coverage

Question 13

another name for a boil

is it purulent or non-purulent SSTI

Answer 13

furuncle

purulent

Question 14

define folliculitis

where is the pus?

Answer 14

very superficial purulent infection of the hair follicles

the pus is only in the EPIDERMIS

Question 15

differentiate between a furuncle and a carbuncle

Answer 15

a furuncle has a single sinus tract. is an inflammatory, draining nodule that involves a hair follicle (purulent)

a carbuncle is when adjacent furuncles (boils) come together to form a single painful area – forms DEEP masses tha open into MULTIPLE sinus tracts

Question 16

what is an abscess

Answer 16

collection of PUS (purulent) within the dermis and the deeper skin tissue

Question 17

treatment for folliculitis

Answer 17

resolves on its own
use warm, moist compress

if however it does NOT resolve on its own, use mupirocin twice a day for 5 days, or even bacitracin

Question 18

furuncle, carbuncle, and abscess treatment (mild vs moderate vs severe)

Answer 18

mild - incision and drainage. ALWAYS done regardless of severity + adjunctive antibiotic if the abscess is greater than 5 cm

moderate - incision and drainage + culture and sensitivity + empiric PO AB’s against MRSA

severe - incision and drainage + culture and sensitivity + empiric IVVVV antibiotics against MRSA

Question 19

as a reminder, name 12 AB’s that cover MRSA

Answer 19

bactrim
doxycycline
tigecycline
vancomycin
daptomycin
linezolid
clindamycin

televancin
oritavancin
dalbavancin

delafloxacin
ceftaroline (5th gen ceph)

Question 20

differentiate between when a purulent infection (aside from folliculitis - so a furuncle, carbuncle, or an absess) can be considered mild vs moderate vs severe when determining treatment

Answer 20

mild - no systemic symptoms

moderate - 1 systemic symptom (ie- fever, white count, hypotension, rapid breathing)

severe - 2 or more systemic or severe signs of the infection. OR failed incision and drainage AND PO antibiotics

Question 21

true or false

in a mild purulent SSTI, there is no antibiotic therapy used

Answer 21

TRUE bc not recommended by IDSA guideleine

HOWEVER, new literature suggests there may be a benefit of using antibiotics against MRSA
-shows lower risk of treatment failure, lower risk of ascess recurrence, and lower risk of hospitalization and surgical procuedure

THEREFORE – if the infection size of the mild SSTI is GREATER THAN 5 CM, we recommend oral antibiotics like doxy or bactrim

Question 22

EMPIRIC antibiotic treatment for MODERATE SSTI

Answer 22

PO bactrim or doxycycline
(want to cover MRSA!!)

Question 23

empiric treatment for SEVERE SSTI

Answer 23

IV antibiotics that cover MRSA -

vanco, dapto, linezolid, telavancin, or ceftaroline

Question 24

DEFINED treatment for moderate SSTI for:

MRSA vs MSSA

Answer 24

MRSA - bactrim

MSSA - dicloxacillin or cephalexin

Question 25

DEFINED treatment for SEVERE SSTI for: MRSA vs MSSA

Answer 25

MRSA - same as empiric (vanco, dapto, linezolid, televancin, ceftaroline) MSSA - nafcillin or cefazolin (1st gen) or clindamycin (if resistance less than 10-15%)

Question 26

what to monitor when doing incision and drainage/adjunctive antibiotic for a mild SSTI

Answer 26

watch for signs that the infection is improving

Question 27

as mentioned, either bactrim or doxy is recommended as empiric treatment for moderate SSTI what are the dosings and monitoring parameters of each

Answer 27

bactrim - 1 ds tab q12 doxy - 100mg q12 monitoring: bactrim - SJS (rash), hyperkalemia, renal function (crystalluria - drink water!!), photosensitivity, hematologic toxicity (monitor CBC if on long time) doxy - photosensitivty, NVD, avoid less than 8 and in pregnant pts

Question 28

important counseling point for patients on bactrim

Answer 28

photosensitive - stay out sun STAY HYDRATED to prevent crystalluria bc affects renal function

Question 29

Vanco dosing for severe SSTI

Answer 29

15mg/kg q12hours

Question 30

what to monitor when administering vanco for a severe SSTI

Answer 30

therapeutic drug monitoring infusion reactions (given IV) renal function

Question 31

what to monitor when administering daptomycin for a severe SSTI

Answer 31

CPK (can cause increased creatinine phosphokinase) myopathy/rhabdomyolysis

Question 32

what to monitor when giving linezolid for a severe SSTI

Answer 32

myelosuppression thrombocytopenia optic neuropathy peripheral neuropathy serotonin syndrome

Question 33

which of the drugs given only for SEVERE SSTI as empiric therapy can cause thrombocytopenia?

Answer 33

LINEZOLID happens around day 7-10 of therapy - very common in older peopl

Question 34

which of the empiric antibiotics given for SEVERE SSTI is not usually combined with serotenergic meds bc of risk of serotonin syndrome

Answer 34

linezolid

Question 35

in purulent SSTIS, ______should be streamlined based on ______

Answer 35

empiric therapy should be streamlined based on CULTURE AND SENSITIVTY RESULTS

Question 36

daptomycin dosing for severe SSTI

Answer 36

4-6mg/kg q24

Question 37

linezolid dosing for severe SSTI

Answer 37

600mgIV (or PO) q12 hours

Question 38

ceftaroline dosing for severe SSTI

Answer 38

400mg IV Q12H

Question 39

typically, the treatment for purulent skin and soft tissue infections lasts....

Answer 39

7-14 days, but it depends on the clinical improvement

Question 40

true or false for purulent skin and soft tissue infections, the antibiotics need to be completed for the full 7-14 days, even if clinical improvement has been noted

Answer 40

FALSE once you see clinical improvement, you can stop them. the lesions do not need to FULLY RESOLVE to stop the antibiotics

Question 41

what should patients with skin and soft tissue infections (purulent) be educated on?

Answer 41

appropriate wound care to avoid recurrent infections

Question 42

25 year old female presents with 7cm abscess of right axilla. no systemic signs of infection and NKA what is the most appropriate treatment for her LATER her I&D was sent for culture and came back as METHICILLIN RESISTANT what is appropriate therapy now? counseling points?

Answer 42

incision and drainage plus bactrim could also be doxy, but bactrim is best CONTINUE BACTRIM!!! COVERS MRSA apply spf, stay hydrated (renal), report any signs of rash, watch for muscle cramping bc sign of hyperkalemia

Question 43

pt in previous example (on bactrim for MRSA mild SSTI) now complains of a rash since starting bactrim now what is the best therapy?

Answer 43

doxycycline - its the other first line for mild SSTI and also covers MRSA

Question 44

define impetigo

Answer 44

contagious SUPERFICIAL infection of the skin, most commonly seen in children

Question 45

2 broad categorizations of impetigo

Answer 45

bullous vs nonbullous

Question 46

difference in the cause (bacteria) of bullous vs nonbullous impetigo

Answer 46

bullous - caused by toxin-producing staph aureus nonbullous - caused by beta hemolytic streptococci and/or staph aureus

Question 47

which is the most common form of impetigo - bullous or nonbullous?

Answer 47

nonbullous

Question 48

differentiate between the physical features of bullous impetigo vs nonbullous

Answer 48

nonbullous - small, fluid-filled vesicles that are like pustules that can rupture. has golden yellow crust bullous - bullae have clear yellow fluid that reptures and is characterized by a thin, light brown crust -- associated with ENLARGED LYMPH NODES

Question 49

treatment for MILD impetigo (just 1 or 2 spots)

Answer 49

topical mupirocin (or even bacitracin) BID for 5 days

Question 50

treatment for impetigo in which there are multiple lesions OR involving the face

Answer 50

PO antibiotics for 7 days

Question 51

as mentioned, when there are multiple impetigo lesions or involving the face, use PO antibiotics for 7 days in general, the agents chose should be active against what?? be specific

Answer 51

STAPH AUREUS for MRSA - give clindamycin, doxy, or bactrim for MSSA - give dicloxacillin or cephalexin or augmentin dependent on RISK FACTORS whether you will give 1 that covers MRSA or not

Question 52

symptomatic relief (not drugs) that the pt can do for impetigo

Answer 52

help the symptoms by removing the crusts by soaking with soap and warm water

Question 53

define erysipelas it is most commonly associated with what bacteria?

Answer 53

cellulitis involving the more superficial layers of the skin and the lymphatics GROUP A STREP (streptococcus pyogenes)

Question 54

drug of choice for erysipelas

Answer 54

penicillin (IV or PO - based on the severity)

Question 55

clinical presentation of erysipelas

Answer 55

continuously red and edematous and indurated (fibrous and hard) spread peripherally, associated with HIGH FEVER, CHILLS, AND GENERAL MALAISE

Question 56

which presents with more systemic symptoms - impetigo or erysipelas?

Answer 56

erysipelas have high fever, chills, and malaise for impetigo its just the skin that's really tight and itchy

Question 57

which PCN are administered IM/IV/PO and how long for erysipelas NOTE: skipped penicillin dosing - waiting for her to reply to email

Answer 57

IM - procaine penicillin G IV - penicillin G PO - Penicillin VK 7-10 days

Question 58

true or false erysipelas does not respond quickly to penicillin treatment

Answer 58

FALSE - it does marked improvement usually seen within 48 hours of treatment

Question 59

explain the areas that cellulitis affects

Answer 59

initially it's just the epidermis and dermis, but may spread to the superficial fascia, lymphatic tissue, and ultimately to the BLOODSTREAM

Question 60

which 2 bacteria frequently cause cellulitis

Answer 60

group A strep (strep pyogenes) staph aureus BOTH ARE GRAM POSITIVE

Question 61

cellulitis may lead to ______ formation, particularly in what 2 scenarios

Answer 61

abscess polymicrobial infection or an anaerobic infection

Question 62

in cellulitis, patients usually have a history of what

Answer 62

wound or trauma

Question 63

clinical presentation of cellulitis

Answer 63

erythema and edema of the skin, warm to touch and PAINFUL lesions NOT ELEVATED with poor defined margins may drain, exudate, or abscess

Question 64

true or false in cellulitis, the lesions are elevated and have poorly defined margins

Answer 64

FALSE not elevated and have poorly defined margins

Question 65

NONPHARMACOLOGIC management of cellulitis

Answer 65

elevate the area and dont move - to decrease swelling use cold compresses for pain use moist heat to help keep the cellulitis local may need surgical debridement to remove the dead or infected tissue --- in COMPLICATED cases

Question 66

in cellulitis, what can be used to try to keep the infection local? what about for pain? what about for swelling?

Answer 66

keep local - moist heat pain - cold compress swelling - elevate it and immobilize

Question 67

what is the term for surgical intervention in cellulitis

Answer 67

debridement

Question 68

antibiotics can be used in cellulitis - either empiric or directed therapy when choosing what to give, what should we be looking at ??

Answer 68

the patient's risk factors and severity for ex - are they an IV drug user? immunocompromised? is an absess forming? etc

Question 69

what do we want to cover if cellulitis is purulent vs non-purulent in mild-moderate cases !!! (outpatient)

Answer 69

non-purulent - just need to cover group A strop if purulent - cover staph (MRSA)

Question 70

which 4 drugs can potentially be used to cover MRSA in mild-moderate outpatient purulent cellulitis (empiric)

Answer 70

bactrim and doxy PO are first line can consider linezolid or tedizolid but they're more $$$ and less tolerated

Question 71

which antibiotics are first line in nonpurulent mild-moderate OUTPATIENT cellulitis (empiric)

Answer 71

want to cover group A strep (strep pyogenes - gram (+)) use PO beta lactams like pen VK, cephalexin, dicloxacillin CAN use later gen PO cephalosporins but they're more money

Question 72

for mild-moderate outpatient cellulitis (whether purulent or non-purulent) how long does empiric treatment last?

Answer 72

around 5 days but it all depends on the clinical response