What are the symptoms and treatment of cellulitis?

Symptoms and Treatment of Cellulitis

Cellulitis is characterized by rapidly spreading areas of erythema, swelling, tenderness, and warmth, often accompanied by lymphangitis and regional lymph node inflammation, and requires prompt antibiotic therapy targeting streptococci and staphylococci. 1

Clinical Presentation

Local Symptoms

• Erythema (redness) that spreads rapidly across the skin surface 1
• Swelling and edema of the affected area 1
• Warmth and tenderness to touch 1, 2
• "Orange peel" appearance (peau d'orange) due to superficial cutaneous edema surrounding hair follicles 1
• Possible development of vesicles, bullae, and cutaneous hemorrhage (petechiae or ecchymoses) 1
• Pain in the affected area 1, 3
• Lymphangitis (inflammation of lymphatic vessels) 1, 3

Systemic Symptoms

• Fever (usually mild but can be severe in some cases) 1, 2
• Tachycardia 1
• Confusion (in severe cases) 1
• Hypotension (in severe cases) 1
• Leukocytosis 1
• Systemic symptoms may precede visible skin changes by hours 1

Diagnosis

Cellulitis is primarily a clinical diagnosis based on physical examination findings 2, 3:

• Blood cultures, tissue aspirates, or skin biopsies are generally unnecessary for typical cases 1
• Blood cultures should be obtained in patients with:
  • Malignancy 1
  • Severe systemic features (high fever, hypotension) 1
  • Unusual predisposing factors (immersion injury, animal bites, neutropenia, severe immunodeficiency) 1

Treatment

Antibiotic Selection

For typical uncomplicated cellulitis, a 5-day course of oral antibiotics targeting streptococci is as effective as a 10-day course, provided clinical improvement occurs by day 5. 1

• First-line oral antibiotics (for mild to moderate cases):

  • Penicillin 1
  • Amoxicillin 1
  • Amoxicillin-clavulanate 1
  • Dicloxacillin 1, 4
  • Cephalexin 1, 4
  • Clindamycin (for penicillin-allergic patients) 1

• For more severe infections requiring parenteral therapy:

  • Beta-lactams (cefazolin, oxacillin) 1
  • Consider hospitalization for:
    • Suspected deeper or necrotizing infection 1
    • Poor adherence to therapy 1
    • Severely immunocompromised patients 1
    • Systemic signs of severe infection 1

MRSA Considerations

• MRSA is an unusual cause of typical cellulitis (treatment success with beta-lactams in 96% of cases) 1

• Consider MRSA coverage in cellulitis associated with:

  • Penetrating trauma, especially from illicit drug use 1
  • Purulent drainage 1
  • Concurrent evidence of MRSA infection elsewhere 1
  • Athletes, children, men who have sex with men, prisoners, military recruits, residents of long-term care facilities, and those with prior MRSA exposure 2

• MRSA treatment options:

  • Intravenous: vancomycin, daptomycin, linezolid, or telavancin 1
  • Oral: doxycycline, clindamycin, or trimethoprim-sulfamethoxazole (SMX-TMP) 1

Additional Management

• Elevation of the affected area to promote drainage of edema and inflammatory substances 1
• Treatment of predisposing conditions 1, 3
• For recurrent cellulitis, consider:
  • Addressing underlying risk factors (chronic edema, tinea pedis, skin lesions) 3
  • Antimicrobial prophylaxis in cases of frequent recurrences 3, 5

Prevention of Recurrence

• Treat predisposing factors like lymphedema, venous insufficiency, or tinea pedis 3, 5
• For recurrent cases, consider:
  • Mupirocin for nasal decolonization 1
  • Daily bathing with chlorhexidine 1
  • Dilute bleach baths (1/4–1/2 cup of bleach per full bath) 1
  • Daily washing of towels, sheets, combs, and razors 1
  • Preventive measures for both patient and household contacts 1

Common Pitfalls

• Misdiagnosing other conditions as cellulitis (venous stasis dermatitis, contact dermatitis, deep vein thrombosis, panniculitis) 4
• Using the term "cellulitis" for cutaneous inflammation associated with collections of pus (proper terms would be "septic bursitis with surrounding inflammation" rather than "septic bursitis with surrounding cellulitis") 1
• Unnecessary broad-spectrum antibiotic coverage when targeted therapy against streptococci and staphylococci is sufficient 1, 2
• Failing to elevate the affected area, which can delay improvement 1
• Not addressing underlying predisposing factors, leading to recurrence 3, 5