What is the initial treatment for a nursing home patient presenting with signs of cellulitis, including left foot swelling, redness, warmth, and pain?

Initial Treatment for Nursing Home Cellulitis

For a nursing home patient with uncomplicated cellulitis of the left foot, initiate oral cephalexin or another beta-lactam antibiotic for 5 days, targeting streptococci and methicillin-sensitive Staphylococcus aureus, with elevation of the affected limb. 1

Antibiotic Selection Algorithm

First-Line Therapy (Standard Cellulitis)

• Prescribe oral cephalexin as the preferred first-line agent for typical cellulitis without purulent drainage or penetrating trauma 1, 2
• Alternative beta-lactams include penicillin or amoxicillin if cephalexin is unavailable 1
• A 5-day course is as effective as 10 days if clinical improvement occurs by day 5 1
• For penicillin-allergic patients, use clindamycin as the alternative 2

When to Add MRSA Coverage

Nursing home residents have specific risk factors that warrant consideration of MRSA coverage 3. Add MRSA-active antibiotics only if the patient has: 1

• Purulent drainage from the affected area
• Penetrating trauma or wound
• Concurrent MRSA infection at another site
• Failed initial beta-lactam therapy after 48 hours

MRSA-Active Regimens (If Indicated)

If MRSA coverage is needed based on the above criteria:

• Oral trimethoprim-sulfamethoxazole (TMP-SMX) plus a beta-lactam (cephalexin or amoxicillin) for dual streptococcal and MRSA coverage 1
• Clindamycin monotherapy provides coverage for both streptococci and MRSA 1
• Doxycycline plus a beta-lactam is another option 1

Important caveat: A double-blind study demonstrated that TMP-SMX plus cephalexin was no more efficacious than cephalexin alone in pure cellulitis without abscess or purulent drainage 1. Therefore, do not empirically add MRSA coverage for typical non-purulent cellulitis, even in nursing homes 1, 4.

Evidence Quality Considerations

The 2014 IDSA guidelines provide the strongest evidence framework, showing that beta-lactam monotherapy was successful in 96% of cellulitis cases, even in settings with high MRSA prevalence for other skin infections 1. This contradicts older observational data from Hawaii (2010) suggesting routine MRSA coverage 5, but the prospective controlled trial data takes precedence 1.

One study showed higher success rates with TMP-SMX versus cephalexin (91% vs 74%) in a MRSA-prevalent area 5, but this conflicts with the more rigorous double-blind trial showing no benefit 1. The higher-quality randomized evidence should guide practice: use beta-lactam monotherapy unless specific MRSA risk factors are present 1.

Adjunctive Measures

Mandatory Supportive Care

• Elevate the affected left foot to promote gravity drainage of edema and inflammatory mediators 1, 2
• Apply warm compresses to improve circulation 2
• Keep skin clean and well-hydrated with emollients 2

Anti-Inflammatory Therapy

• Consider adding oral prednisone 40 mg daily for 7 days in non-diabetic patients to hasten resolution 1
• Alternative: ibuprofen 400 mg every 6 hours for 5 days significantly shortened time to complete resolution (all patients resolved in 4-5 days versus up to 7+ days with antibiotics alone) 6
• Do not use corticosteroids if the patient is diabetic 1

Address Predisposing Factors

• Treat tinea pedis or other toe web abnormalities 1
• Manage venous insufficiency or lymphedema 1
• Address any trauma or skin breakdown 1

Monitoring and Follow-Up

Expected Clinical Course

• Reassess within 48 hours to ensure clinical improvement 2
• Cutaneous inflammation may paradoxically worsen in the first 24-48 hours due to pathogen destruction releasing inflammatory enzymes—this is expected and does not indicate treatment failure 1, 2
• If no improvement by 48 hours, consider MRSA coverage or alternative diagnoses 2, 3

Red Flags Requiring Hospitalization

• Fever, delirium, or hypotension 1
• Rapidly spreading erythema despite treatment 2
• Systemic signs of sepsis 2

Common Pitfalls to Avoid

Do not routinely prescribe 10-day courses—5 days is sufficient with clinical improvement 1. Do not add empiric MRSA coverage for typical non-purulent cellulitis—this increases costs and adverse effects without improving outcomes 1, 4. Do not misdiagnose pseudocellulitis (venous stasis dermatitis, contact dermatitis, eczema) as infection, which occurs frequently and leads to unnecessary antibiotic exposure 3, 4.