What are the appropriate antibiotics for an elderly female with left leg cellulitis?

Antibiotic Treatment for Left Leg Cellulitis in Elderly Female

For an elderly female with left leg cellulitis, a 5-6 day course of antibiotics active against streptococci is recommended, with cephalexin being the first-line treatment option in the absence of MRSA risk factors. 1

First-Line Treatment Options

• Cephalexin (500 mg orally four times daily for 5-6 days) is the preferred first-line treatment as streptococci are the most common causative pathogens in lower extremity cellulitis 1
• Treatment duration should be 5-6 days for uncomplicated cellulitis in patients who can self-monitor and have close follow-up 1
• Consider extending treatment if the infection has not improved after 5 days 1

Alternative Options (for Penicillin/Cephalosporin Allergies)

• Clindamycin (300-450 mg orally four times daily for 5 days) is the preferred alternative for patients with penicillin or cephalosporin allergies 2
• Other alternatives include macrolides, though resistance rates are increasing 1

When to Consider MRSA Coverage

MRSA is an unusual cause of typical cellulitis, but coverage should be considered in specific situations:

• Presence of purulent drainage 1, 2
• Evidence of MRSA infection elsewhere 1, 2
• History of penetrating trauma, especially from illicit drug use 1, 2
• Presence of systemic inflammatory response syndrome 1, 2
• History of previous MRSA infections 1

MRSA Treatment Options

If MRSA coverage is warranted, consider:

• Oral options: trimethoprim-sulfamethoxazole, doxycycline, or clindamycin 1, 2, 3
• For combination coverage of both streptococci and MRSA, options include clindamycin alone or the combination of either trimethoprim-sulfamethoxazole or doxycycline with a β-lactam 1
• For severe infections requiring parenteral therapy: vancomycin, linezolid, or telavancin 1, 4

Parenteral Therapy Indications

Consider intravenous antibiotics if:

• Severe infection with systemic symptoms 1
• Failed oral therapy 1
• Immunocompromised status 1, 2
• Rapidly progressing infection 1

Adjunctive Measures

• Elevation of the affected limb to promote gravity drainage of edema and inflammatory substances 1, 2
• Treatment of predisposing conditions such as tinea pedis, venous insufficiency, or underlying skin disorders 1, 2
• Systemic corticosteroids may be considered in non-diabetic patients to reduce inflammation (prednisone 40 mg daily for 7 days), though this remains a weak recommendation 1
• Non-steroidal anti-inflammatory drugs may help hasten resolution of inflammation when added to antibiotic therapy 5

Prevention of Recurrence

For patients with recurrent cellulitis:

• Identify and treat predisposing factors such as edema, venous insufficiency, tinea pedis, or toe web abnormalities 1, 6
• For patients with 3-4 episodes per year despite addressing predisposing factors, prophylactic antibiotics such as penicillin can reduce recurrence rates 1, 6
• Prophylactic penicillin (250 mg twice daily) has been shown to be effective in preventing recurrent episodes, with a number needed to treat of 5 6

Monitoring Response

• Assess for clinical improvement within 48-72 hours, including reduction in erythema, swelling, pain, and resolution of systemic symptoms if present 2
• If no improvement is seen within 5 days, consider extending treatment duration or changing antibiotics 1