Recognizing the Cellulitis Presentation

History: Acute onset of localized skin redness, warmth, swelling, and pain; may follow a break in skin (wound, insect bite, tinea pedis, surgical site)
Physical Exam: Unilateral erythema with poorly defined margins, warmth, edema, and tenderness; possible lymphangitic streaking or regional lymphadenopathy
Purulence Assessment: Evaluate for fluctuance suggesting underlying abscess; purulent drainage points toward MRSA and requires incision and drainage
Systemic Signs: Fever, chills, tachycardia, and malaise suggest more severe infection or bacteremia
Vital Signs: May be normal in uncomplicated cellulitis; fever and tachycardia suggest systemic involvement
Risk Factors: Diabetes, obesity, peripheral vascular disease, lymphedema, immunosuppression, prior episodes of cellulitis, and tinea pedis

Immediate Actions (First 5 Minutes)

These orders should be placed immediately — timing is scored:

✓ Mark borders of erythema with skin marker and document time
✓ Elevate affected extremity
✓ Assess for fluctuance and underlying abscess (consider bedside ultrasound)
✓ Obtain vital signs and assess for systemic toxicity (SIRS criteria)
✓ Administer antipyretic (acetaminophen or ibuprofen) for pain and fever

After initial stabilization, complete the diagnostic workup:

Clinical diagnosis (imaging and labs often unnecessary in uncomplicated cases)
CBC with differential if systemic signs present
BMP if diabetic or renal disease
Blood cultures (two sets) if febrile, immunocompromised, or signs of systemic toxicity
Wound culture if purulent drainage or open wound present
Point-of-care ultrasound to evaluate for abscess if fluctuance suspected
X-ray of affected area if concern for gas gangrene, foreign body, or osteomyelitis
HbA1c if new or poorly controlled diabetic
CRP or ESR if needed to track treatment response or differentiate from deeper infection

Cephalexin 500 mg PO QID for 5-7 days (first-line for non-purulent cellulitis)
Amoxicillin-clavulanate 875/125 mg PO BID as alternative
Clindamycin 300-450 mg PO TID if penicillin allergy
Add TMP-SMX 1-2 DS tablets PO BID or doxycycline 100 mg PO BID if MRSA coverage needed

Cefazolin 1-2 g IV every 8 hours for non-purulent cellulitis requiring IV therapy
Vancomycin 15-20 mg/kg IV every 8-12 hours if MRSA suspected or purulent with systemic signs
Piperacillin-tazobactam if polymicrobial or diabetic foot infection
Step down to oral antibiotics when afebrile and improving for 24-48 hours

Incision and drainage is primary treatment for cutaneous abscess
Send wound culture and sensitivity from abscess cavity
Pack wound and arrange follow-up for packing removal in 48 hours
Antibiotics indicated for abscess if surrounding cellulitis, systemic signs, or immunocompromised

Scoring Tip: These are the most commonly missed actions for Cellulitis cases.

Not marking the borders of erythema to track progression (important CCS order)
Missing an underlying abscess that requires incision and drainage
Using IV antibiotics for uncomplicated cellulitis that can be treated orally
Not covering MRSA in purulent cellulitis (add TMP-SMX or doxycycline)
Failing to obtain blood cultures in patients with systemic signs or immunosuppression
Confusing cellulitis with deep venous thrombosis (both present with unilateral leg swelling)
Not treating underlying tinea pedis as a portal of entry for recurrent cellulitis

Discharge home with oral antibiotics for uncomplicated cellulitis in immunocompetent patients
Admit for IV antibiotics if systemic toxicity, failed outpatient therapy, immunocompromised, or rapid progression
Arrange outpatient follow-up in 48-72 hours to reassess borders and treatment response
Surgical consult if concern for necrotizing fasciitis (pain out of proportion, crepitus, rapid spread, hemodynamic instability)

Apply these strategies with our realistic Cellulitis simulations and get instant AI feedback.