MEDICAL DECISION MAKING

Most of the time, a good history and physical examination

are all that is needed to make the diagnosis of a soft tissue

infection. A patient with cellulitis will likely present with a

history of an injury to the skin who then develops superficial erythema, warmth, swelling, and pain. A thorough

history and physical will allow differentiation of cellulitis

from other diagnoses such as thrombophlebitis, viral and

drug exanthems, dermatitis, allergic reactions, insect bites,

lymphedema, or fungal infections.

Sometimes a cutaneous abscess can be present along with

superficial cellulitis. In these cases, bedside ultrasound

becomes useful in determining whether a pus collection has

developed underneath the skin. The differential diagnosis for

abscess includes cutaneous cysts, t urnors, foreign body granulomas, or vascular malformations (especially in the axilla and

groin). Knowing the features of an abscess (erythema, in duration, fluctuance, and a focal area of pain) becomes important,

as only an abscess will have all of those features.

If a necrotizing infection (presence of pain out of pro ­

portion to exam, crepitus, bullae formation, skin sloughing, or systemic toxicity) is suspected, it becomes vital that

an urgent CT scan is ordered to assess for gas and the

extent of infectious involvement. A necrotizing infection

requires prompt identification, consultation, and treatment (Figure 36-3).

History & physical exam

Cellulitis: superficial erythema,

wa rmth, swelling, pain

Systemic symptoms,

immunocompromise,

extensive i nvolvement

No:

DC with PO

antibiotics,

elevate and

recheck in

24-48 hr

Yes:

La b studies,

consider imagi ng,

and admit for IV

antibiotics

Abscess: focal area of pain,

redness, fluctuance, and

induration

No:

All get I&D in ED:

wound cultures if

suspected M RSA

or necrotizing

infection

Systemic symptoms,

immu nocompromise,

extensive involvement

Yes:

DC with

packing removal

in 24-48 hr

La b studies, imag ing,

and admit for IV

antibiotics

Figure 36-3. Soft tissue infections diagnostic algorithm. DC, discharge; ED, emergency depa rtment; I&D,

incision and drainage; IV, i ntravenous; MRSA, methici llin-resistant Staphylococcus aureus .

SOFT TISSUE I NFECTIONS

TREATMENT

Cellulitis is treated with antibiotics. If there is systemic

toxicity, immune compromise, or involvement of high-risk

areas (hands, face, perineum, or circumferential extremity)

the patient should receive IV antibiotics and admission. If

none of the above is present, the patient can be discharged

with oral antibiotics (7- to 1 0-day course) and instructions

to be rechecked in 2 days.

Incision and drainage (I&D) is the treatment of choice

for an abscess, most of which do not require antibiotics

after I&D. The abscess should be packed and a recheck

scheduled in 1 -2 days. Indications for the addition of antibiotics include systemic symptoms, extensive surrounding

cellulitis, or immune compromise.

Treatment of a necrotizing infection involves prompt

fluid resuscitation and N antibiotics. Consultation with a

general surgeon should be performed for emergent

debridement to stop the advancement of the infection.

Empiric broad-spectrum antibiotic coverage should be

initiated. Piperacillin/tawbactam with vancomycin and

ciprofloxacin is the initial treatment of choice, as it covers

mixed aerobic and anaerobic bacteria that are often

involved. Vancomycin is being used because high rates of

MRSA resistance to clindamycin have been found.

However, clindamycin is often added to the preceding

regimen, as it has been shown to have bacterial toxin suppressive properties.