Cellulitis Flashcards
What are SSTIs?
skin and soft tissue infections
How are SSTIs divided?
purulent (pus): bullous impetigo, carbuncles, cutaneous abscess, folliculitis, purulent cellulitis
non-purulent (no pus): non-bullous impetigo, non-purulent cellulitis
Which tissues does cellulitis hit?
initially affects epidermis and dermis
may spread within superficial fascia
may spread through lymphatic tissue and bloodstream
What are the symptoms of cellulitis?
affected area is hot and painful
erythema
inflammation (edema) with little or no necrosis or suppuration of soft tissue
may be associated with purulent drainage, exudates and/or abscess
tender lymphadenopathy
fever, chills, malaise
What do people with cellulitis often have a history of?
antecedent minor trauma
abrasion
ulcer
surgery
Which areas of the body are commonly hit by cellulitis?
hands
feet
lower legs (differ from venous stasis; bilateral, not hot)
peri-orbital (more common in kids, H. influenzae)
True or false: cellulitis is typically bilateral
false
typically unilateral
bilateral should prompt consideration of other diagnoses
What are the microorganisms that cause cellulitis?
group A strep
staph aureus
-MSSA: sensitive to cloxacillin
-MRSA: not susceptible to beta-lactam antibiotics
-CA-MRSA: onset in community without health-care associated
risk factors
-HCA-MRSA: health care associated MRSA
Which class of antibiotics should never be given for MRSA?
beta-lactams
In terms of purulent vs non-purulent cellulitis, which organisms are more likely to cause each?
non-purulent: group A strep
purulent: S. aureus
What are the risk factors for CA-MRSA?
5 C’s: crowding, frequent skin contact, compromised skin, sharing contaminated personal items, lack of cleanliness
age <2yrs and >65yrs
athletes of contact sports
men who have sex with men
living in correctional facilities
history of colonization or recent infection with CA-MRSA
antibiotic use in last 6 months
recent invasive procedures
IV drug use
military personnel
homeless persons
prior hospitalization for SSTI
trauma associated
When should you cover for MRSA?
patient from highly endemic area for CA-MRSA
CA-MRSA risk factors
lack of improvement on beta-lactams
clinical judgement (serious illness, immunocompromised)
True or false: SSTIs often respond to therapy that does not cover CA-MRSA even if MRSA is endemic or cultured
true
What are the distinguishable signs of CA-MRSA from other organisms?
no reliable signs
What is the antibiotic choice for non-purulent cellulitis?
cephalexin
What is the dosing of cephalexin for non-purulent cellulitis in adults?
500mg po QID
What is the dosing of cephalexin for non-purulent cellulitis in pediatrics?
50-100mg/kg/d QID
What is the susceptibility of GAS isolates in Saskatoon and Regina to cephalexin?
100%
Which potentially causative organism of cellulitis will cephalexin not cover?
MRSA
What are the antibiotic choices for penicillin allergic patients for non-purulent cellulitis?
clindamycin
erythromycin
What is the dosing of clindamycin in adults for non-purulent cellulitis? What about kids?
adults: 300mg po QID or 450mg po TID
children: 20-40mg/kg/d po TID or QID
What is the dosing of erythromycin in adults for non-purulent cellulitis? What about kids?
adults: 250mg po QID or 500mg po BID
kids: 30-40mg/kg/d po BID
What are the choices of antibiotics for purulent cellulitis, assuming it is MSSA?
cephalexin (same doses)
cloxacillin
What is the dosing of cephalexin in adults for purulent cellulitis? What about kids?
500mg po QID
50-100mg/kg/day QID
