Skin and Soft Tissue Infections - Cellulitis

Question 1

For non-purulent cellulitis, what is first-line treatment?

Most likely GAS

Answer 1

Cephalexin

100% susceptibility

Question 2

Optimal dosing of cephalexin for adults is:

Cellulitis

Answer 2

500mg po QID

Question 3

Optimal dosing of cephalexin for pediatrics is:

Cellulitis

Answer 3

50 - 100 mg/kg/day, divided QID

QID can be hard to be compliant with

Question 4

If an individual has a true penicillin allergy, what is an alternative choice?

Answer 4

Clindamycin or Erythromycin

Resistance rates are higher (7-20%)

Question 5

For purulent cellulitis (MSSA), what are 1st line treatment options?

Not suspecting MRSA

Answer 5

Cephalexin or Cloxacillin

Question 6

Optimal dosing of cloxacillin for adults is:

Cellulitis

Answer 6

500 mg po QID

Question 7

Optimal dosing of cloxacillin for pediatrics is:

Answer 7

50 mg/kg/day divided QID

Question 8

If MRSA is suspected, or the patient has a true penicillin allergy, what antibiotics could be given?

Answer 8

TMP/SMX or Doxycycline

Little resistance

Both BID

Question 9

Clindamycin should be avoided when MRSA is suspected, because:

Answer 9

Resistance issues

~73% susceptibility, better options

HOWEVER, can potentially cover GAS and MRSA - but resistant

Question 10

Ciprofloxacin should not be used in cases of cellulitis because:

Answer 10

It does not cover the likely organisms and has high resistance rates

Mostly for G- bacilli and pseudomonal infections

Question 11

Empiric therapy that can cover for GAS and MRSA include the two following antibiotics:

Answer 11

Cephalexin + TMP/SMX or doxycycline

Cephalexin covers GAS, others cover MRSA

Question 12

For uncomplicated cellulitis, how many days of treatment is sufficient?

Answer 12

5 days

5 days as effective as 10 days, given evidence of clinical improvement

Question 13

Timeline of cellulitis recovery (after incision, drainage, and antibiotics) is unique because:

Answer 13

Condition may worsen in the first few days

Part of healing process, not treatment failure

Question 14

How long may full skin healing take (reduction of inflammation and symptoms)?

Answer 14

1-2 weeks after antibiotics are stopped

Question 15

What are two non-pharmacological methods that are key to successful cellultis therapy?

Answer 15

Incision and drainage (especially for purulent)
Elevation of affected limb (help edema subside)

For abscesses <5cm, I&D alone may be sufficient

Question 16

What are the two categories that SSTI’s are split into?

Answer 16

Purulent and Non-purulent

Purulent = pus present

Question 17

What parts of the skin does cellulitis affect?

Answer 17

Epidermis and dermis, may spread within superficial fascia

Question 18

A serious consequence of cellulitis is this complication:

Answer 18

Spread through lymphatic tissue and bloodstream

…But is usually self-limiting

Question 19

Common S/Sx of cellulitis involving the skin include:

Answer 19

Affected area is hot and painful - erythema + edema of skin, inflammation (little/no necrosis)
Purulent drainage, exudates, or abscess may be involved

Question 20

What patient history is common in cellulitis cases?

Answer 20

Antecedent minor trauma, abrasion, ulcer, or surgery

Question 21

Other common symptoms involved in cellulitis infection include:

Answer 21

Tender lymphadenopathy
Fever, chills, malaise

Question 22

Sx’s signifying a severe cellulitis infection include:

Systemic

Answer 22

Hypotension, dehydration, altered mental status

Question 23

What are the two microorganisms involved in SSTI’s?

Answer 23

Group A Streptococcus
Staphylococcus aureus

Question 24

Staphylococcus Aureus can be categorized into the two following groups:

Answer 24

MSSA - susceptible to methicillin
MRSA - not susceptible to beta-lactam antibiotics

Question 25

If a patient presents with non-purulent cellulitis, what microorganism should we suspect?

Answer 25

Predominantly Strep (GAS)

Lower rate of staph

Question 26

If a patient presents with purulent cellulitis, which organism should we suspect?

Answer 26

Predominantly Staph Aureus

Question 27

What are the 5 C’s for MRSA risk factors?

Answer 27

Crowding, frequent skin contact, compromised skin, sharing of contaminated personal items, lack of cleanliness

Question 28

What are some other important risk factors to consider for MRSA infections?

Answer 28

History of colonization/recent MRSA infection
Antibiotic use in last 6 months
IV drug use
Any occupation or lifestyle involving close contacts (correctional facilities, military, homelessness)

Question 29

When should we cover for MRSA?

Answer 29

MRSA risk factors present
Highly endemic area for MRSA
Clinical judgement of illness, and lack of improvement on a beta-lactam

SSTI’s often respond to therapy not covering for MRSA even if it was cultured, so condition can be self-limiting

Question 30

Does MRSA have any identifiable S/Sx’s from other microorganisms?

Answer 30

No reliable signs or symptoms of differentiation