Ten Cellulitis Myths Busted

Spoon Feed
This was a fun article that searched the literature and dispensed with 10 myths about cellulitis.

Why does this matter?
Admissions for cellulitis have a huge economic impact and use valuable bed space in the hospital.  And it is often misdiagnosed.  Accurate diagnosis may reduce admissions and improve antibiotic stewardship.

Man, that looks red!
Myth 1 - Red = cellulitis

  • Stasis dermatitis, DVT, gout, allergic reactions, and other skin conditions are also red.
  • Elevation of the limb 45 degrees for 2 minutes will often make redness fade in most non-infectious causes, but redness will remain in cellulitis.

Myth 2 - My patient has bilateral leg cellulitis.

  • This is exceedingly rare.  There would have to be simultaneous inoculation of both legs.
  • It's probably stasis dermatitis or something else.

Myth 3 - All skin infections need antibiotics.

  • Very small abscesses may not need antibiotics.  (But see this NEJM paper we will cover later this month...)
  • Small areas of erythema, < 5 cm, may also not need antibiotics, especially if no systemic signs and not diabetic or immunocompromised.

Myth 4 - All skin infections need MRSA coverage.

  • Skin infection confirmed to not have an abscess does not benefit from adding TMP/SMX to cephalexin.
  • Furuncles should have MRSA coverage.
  • Consider your local infection patterns and the patient's risk for MRSA.

Myth 5 - Admissions for cellulitis need MRSA coverage.

  • See Myth 4 discussion.
  • If patients are systemically ill, an antibiotic with MRSA coverage is not a bad idea.

Myth 6 - Clindamycin will cover MRSA.

  • It depends on local resistance patterns at your facility.  Resistance may be as high as 35% in some areas.
  • Most MRSA strains remain sensitive to TMP/SMX and doxycycline.

Myth 7 - One also needs to add coverage for gram-negatives and anaerobes.  Maybe, but only if:

  • "Intensive care unit (ICU) level of care
  • Concern for bloodstream or necrotizing infection
  • Peri-rectal involvement, peri-orbital involvement, human or animal bite, surgical wound infection, traumatic aquatic injury, or osteomyelitis
  • Chronic diabetic foot wounds
  • Intravenous illicit drug use
  • Presence of neutropenia or severe cell-mediated immunodeficiency

Myth 8 - If redness goes beyond the margin previously traced out, it is getting worse.

  • This may be true, but in the first 48 hours, infection may spread a little while on antibiotics.
  • Spreading redness and fever should be considered a treatment failure if beyond 48 hours on antibiotics.

Myth 9 - Repeat infection will not happen in patients taking antibiotic prophylaxis.

  • Not true.
  • If skin is cracked, fungal infection is present, or chronic edema remains, infection may still recur.

Myth 10 - Redness around tick bites indicates cellulitis.

  • This is most often an inflammatory response to the bite.
  • Be wary of erythema migrans in Lyme-endemic areas.

Top 10 Myths Regarding the Diagnosis and Treatment of Cellulitis.  J Emerg Med. 2017 Jul 3. pii: S0736-4679(17)30436-5. doi: 10.1016/j.jemermed.2017.05.007. [Epub ahead of print]

Another Spoonful
Don't miss this core knowledge post on emDocs, Cellulitis Mimics.

Peer reviewed by Thomas Davis, MD.

Member Login
Welcome, (First Name)!

Forgot? Show
Log In
Enter Member Area
My Profile Sign up to get full access. Log Out