What is the first-line therapy for non-suppurative (not producing pus) cellulitis?

First-Line Therapy for Non-Suppurative Cellulitis

For non-suppurative cellulitis, the first-line therapy is an antimicrobial agent active against streptococci, such as cephalexin 500 mg orally 3-4 times daily for 5 days. 1

Treatment Algorithm

Initial Assessment and Treatment

1. Antimicrobial Selection:

   • Mild infection without MRSA risk factors:
     • Cephalexin 500 mg orally 3-4 times daily for 5 days OR
     • Amoxicillin-clavulanate 875/125 mg twice daily for 5 days 1

2. Adjunctive Measures:

   • Elevation of the affected limb (strong recommendation) 1
   • Careful examination and treatment of interdigital spaces for any fissuring, scaling, or maceration 1
   • Consider systemic corticosteroids (prednisone 40 mg daily for 7 days) in non-diabetic patients 1

Treatment Based on Severity

• Moderate infection or MRSA risk factors:

  • Clindamycin 300-450 mg orally three times daily for 5-6 days 1

• Severe infection:

  • Vancomycin plus either piperacillin-tazobactam or imipenem/meropenem 1

Key Considerations

Pathogen Coverage

The majority of non-purulent cellulitis cases are caused by β-hemolytic streptococci or methicillin-sensitive Staphylococcus aureus (MSSA) 2, 3. Therefore, antibiotics targeting these organisms are appropriate first-line therapy.

Duration of Therapy

Five days of treatment is sufficient for most cases of uncomplicated cellulitis, with extension if symptoms have not improved 1, 2. Patients should be monitored for improvement within 72 hours of starting treatment 1.

MRSA Coverage

Despite rising rates of community-acquired MRSA, coverage for non-purulent cellulitis is generally not recommended unless specific risk factors are present 3. Risk factors for MRSA include:

• Athletes
• Children
• Men who have sex with men
• Prisoners
• Military recruits
• Residents of long-term care facilities
• Prior MRSA exposure
• Intravenous drug users 2

Common Pitfalls and How to Avoid Them

1. Failure to examine interdigital spaces:

   • Always examine between toes for fissuring, scaling, or maceration that may harbor pathogens 1

2. Inadequate elevation of the affected limb:

   • Ensure proper elevation instructions are given to patients as this is a strong recommendation for treatment 1

3. Overlooking predisposing conditions:

   • Address underlying factors such as edema, obesity, eczema, and venous insufficiency 1

4. Excessive treatment duration:

   • Five days is typically sufficient; extending beyond this is unnecessary unless improvement is not seen 1

5. Unnecessary MRSA coverage:

   • In areas with low MRSA prevalence, avoid routine MRSA coverage for non-purulent cellulitis 1, 3

6. Failure to distinguish cellulitis from pseudocellulitis:

   • Consider non-infectious mimickers such as venous stasis dermatitis, contact dermatitis, eczema, lymphedema 3

Patient Education and Follow-up

• Inform patients that residual lumps are normal and represent healing tissue 1
• Advise that lumps will likely resolve gradually over weeks to months 1
• Provide clear return precautions 1
• Schedule routine follow-up in 2-4 weeks to ensure continued resolution 1
• For patients with edema, recommend restricting dietary sodium (<2.0 g/d) 1

Medication Considerations

When prescribing cephalexin, be aware that:

• It should only be used for proven or strongly suspected bacterial infections to prevent antibiotic resistance 4
• Patients should be monitored for allergic reactions 4
• Prolonged use may result in overgrowth of nonsusceptible organisms 4
• Dose adjustments may be needed in patients with markedly impaired renal function 4