What is the recommended treatment for uncomplicated cellulitis?

Treatment of Uncomplicated Cellulitis

For uncomplicated cellulitis, the recommended first-line treatment is a 5-day course of antibiotics targeting Streptococcus and methicillin-sensitive Staphylococcus aureus (MSSA), such as cephalexin 500 mg four times daily or amoxicillin-clavulanate 875/125 mg twice daily. 1

Antibiotic Selection

First-line options (oral therapy):

• Cephalexin 500 mg four times daily for 5 days
• Amoxicillin-clavulanate 875/125 mg twice daily for 5 days
• Cloxacillin 500 mg four times daily for 5 days
• Dicloxacillin (dosage based on weight) for 5 days

For penicillin-allergic patients:

• Clindamycin 300-450 mg orally three times daily for 5 days
• Doxycycline 100 mg twice daily for 5 days (avoid in children under 8 years)

For severe cases requiring parenteral therapy:

• Nafcillin
• Cefazolin
• Clindamycin or vancomycin (for patients with life-threatening penicillin allergies) 2

Duration of Treatment

A 5-day course of antibiotics is as effective as a 10-day course for uncomplicated cellulitis 2, 3. In a randomized, double-blind, placebo-controlled trial, 5 days of therapy with levofloxacin was shown to be equally effective as 10 days of therapy, with a 98% success rate in both groups 3.

MRSA Considerations

For uncomplicated, non-purulent cellulitis, MRSA coverage is generally not necessary 4. However, MRSA coverage should be considered in specific high-risk populations:

• Athletes
• Children
• Men who have sex with men
• Prisoners
• Military recruits
• Residents of long-term care facilities
• Those with prior MRSA exposure
• Intravenous drug users 5

If MRSA coverage is needed, options include:

• Trimethoprim-sulfamethoxazole 1-2 DS tablets twice daily
• Doxycycline 100 mg twice daily
• Clindamycin 300-450 mg orally three times daily
• Linezolid 600 mg twice daily 1

Adjunctive Measures

1. Elevation of the affected area - This important and often neglected aspect of treatment promotes gravity drainage of edema and inflammatory substances 2, 1
2. Keep the area clean and dry - Daily cleansing with chlorhexidine or povidone-iodine solution may be considered 1
3. Address underlying conditions - Treat predisposing factors such as tinea pedis, venous eczema, or trauma 2

Management of Recurrent Cellulitis

For patients with 3-4 episodes of cellulitis per year despite addressing predisposing factors, consider prophylactic antibiotics:

• Oral penicillin V 1 g twice daily
• Erythromycin 250 mg twice daily
• Intramuscular benzathine penicillin 1.2 million units every 2-4 weeks 2, 1

Common Pitfalls to Avoid

1. Misdiagnosis - Cellulitis can be confused with conditions like venous stasis dermatitis, contact dermatitis, eczema, and lymphedema 4
2. Failure to address predisposing factors - Treating underlying conditions is essential for preventing recurrence 1
3. Inadequate treatment duration - While 5 days is typically sufficient, therapy should be extended if clinical response is inadequate 1
4. Overuse of broad-spectrum antibiotics - Vancomycin and newer agents should be reserved for severe infections or confirmed MRSA 1
5. Failure to drain purulent collections - Antibiotics alone are often insufficient for abscesses 1

Response to Treatment

If there is no improvement within 2-3 days of starting appropriate antibiotics, consider:

1. Resistant organisms
2. Secondary conditions that mimic cellulitis
3. Underlying complicating conditions (immunosuppression, chronic liver disease, chronic kidney disease) 5

In cases of slow response, systemic corticosteroids may be considered as an adjunct in selected adult patients without diabetes or pregnancy to hasten resolution 2.