What treatment is recommended for recurrent erythema of the great toe, which was previously cleared with Keflex (cephalexin) antibiotic?

Treatment for Recurrent Erythema of the Great Toe

For recurrent cellulitis of the great toe that previously responded to cephalexin, switch to clindamycin 300-450 mg orally four times daily for 5-10 days as your next empiric antibiotic choice. 1

Immediate Treatment Approach

• Clindamycin provides superior coverage against both beta-hemolytic streptococci and Staphylococcus aureus compared to cephalexin, making it the recommended next-line agent for cellulitis that has recurred after initial cephalexin treatment 1

• Alternative option: Amoxicillin-clavulanate offers broader coverage than cephalexin and is effective against beta-lactamase-producing organisms that may be contributing to treatment failure 1

• Treatment duration should be 5 days if clinical improvement occurs within this timeframe; extend treatment if no improvement is seen by day 5 2, 1

Critical Adjunctive Measures

• Elevate the affected foot consistently to promote gravity drainage of edema and inflammatory substances—this is often neglected but accelerates healing 2, 1

• Mark the borders of erythema with a pen to objectively monitor whether the infection is progressing or improving 1

• Examine for and treat predisposing conditions including:

  • Interdigital tinea pedis (athlete's foot between toes) 2
  • Interdigital maceration 2
  • Venous insufficiency 2
  • Skin dryness and cracking 2

Prevention of Future Recurrences

Address underlying risk factors immediately to prevent the lymphatic damage that occurs with each cellulitis episode, which can lead to chronic lymphedema 2

• Keep skin well hydrated with emollients to prevent dryness and cracking that serve as portals of entry 2, 1

• Treat any tinea pedis aggressively with antifungal therapy, as fungal infection between the toes is a major predisposing factor 2, 1

• Consider prophylactic antibiotics if you experience 3-4 episodes per year despite treating predisposing factors 2:

  • Monthly intramuscular benzathine penicillin 1.2 million units, OR
  • Oral penicillin V 1 g twice daily, OR
  • Oral erythromycin 250 mg twice daily 2

• Continue prophylaxis as long as predisposing factors persist 2

Important Clinical Pitfalls

• First-generation cephalosporins like cephalexin are ineffective against Borrelia burgdorferi (Lyme disease), which can present with erythema and was actually cultured from patients who "failed" cephalexin treatment 2, 1—consider Lyme disease if there is tick exposure history

• Macrolides should not be used as first-line therapy due to increasing resistance among group A streptococci 1

• Watch for signs of deeper infection requiring surgical consultation: wooden-hard feel to subcutaneous tissues, skin anesthesia, rapid progression, or systemic toxicity suggesting necrotizing fasciitis 2, 1

• Each cellulitis episode causes permanent lymphatic damage, making prevention of recurrence critical to avoid progressive lymphedema 2

Monitoring Response

• Expect initial worsening in the first 24 hours due to bacterial lysis releasing inflammatory enzymes—this does not indicate treatment failure 2

• If no improvement by 5 days, consider deeper infection, resistant organisms (including community-acquired MRSA), or unaddressed predisposing conditions 2, 1

• Patients slow to respond may have underlying diabetes, chronic venous insufficiency, or lymphedema that requires concurrent management 2