What is the treatment for erythema nodosum secondary to streptococcal infection?

Treatment of Erythema Nodosum Secondary to Streptococcal Infection

The treatment of erythema nodosum secondary to streptococcal infection should include antibiotics targeting streptococci (penicillin or amoxicillin) for 10-14 days, along with NSAIDs for symptomatic relief of pain and inflammation.

Pathophysiology and Clinical Presentation

Erythema nodosum (EN) is the most common form of panniculitis characterized by:

• Tender, erythematous, subcutaneous nodules
• Typically located symmetrically on the anterior surface of lower extremities (pretibial area)
• Often accompanied by fever and arthralgia in more than 50% of cases
• Self-limited condition that resolves without scarring

Streptococcal infection is the most common identifiable cause of erythema nodosum in children and one of the most common causes in adults 1.

Treatment Algorithm

1. Antimicrobial Therapy

• First-line treatment: Penicillin or amoxicillin for 10-14 days 2, 3

  • Amoxicillin: 500 mg orally three times daily for adults 4
  • Must continue treatment for at least 10 days for streptococcal infections to prevent acute rheumatic fever 4

• For penicillin-allergic patients:

  • Erythromycin or clindamycin 2
  • Clindamycin: 300-450 mg orally three times daily 5

2. Symptomatic Treatment

• NSAIDs for pain and inflammation 6, 1

  • Options include acetylsalicylic acid, ibuprofen, naproxen, or indomethacin
  • Continue until symptoms resolve

• Rest and elevation of the affected limbs 5

• Avoid systemic corticosteroids unless severe symptoms are present 6

  • Despite rapid response to corticosteroids, their use is generally not recommended or necessary for uncomplicated cases

3. Treatment of Underlying Condition

• Ensure complete eradication of streptococcal infection 3
• Monitor resolution with follow-up ASO (antistreptolysin-O) titers if needed 3

Special Considerations

Monitoring and Follow-up

• Evaluate clinical response within 48-72 hours of initiating antibiotics 5
• Complete resolution typically occurs within 3-6 weeks
• No scarring should occur after resolution 1

When to Consider Additional Evaluation

• Persistent symptoms despite appropriate therapy
• Recurrent episodes
• Presence of systemic symptoms suggesting alternative diagnoses

Pregnancy Considerations

• Erythema nodosum can occur during pregnancy with streptococcal infection 3
• Amoxicillin is generally considered safe in pregnancy (Category B) 5

Pitfalls and Caveats

1. Avoid premature discontinuation of antibiotics

   • Complete the full 10-14 day course to prevent complications like acute rheumatic fever 4

2. Differential diagnosis

   • Rule out other causes of EN before attributing solely to streptococcal infection
   • Consider sarcoidosis, tuberculosis, inflammatory bowel disease, and other infections 7

3. Unnecessary use of corticosteroids

   • While effective for symptom relief, systemic corticosteroids are generally not recommended for uncomplicated EN 6
   • Reserve for severe cases unresponsive to NSAIDs and antibiotics

4. Failure to identify and treat the underlying cause

   • Treatment of the underlying streptococcal infection is essential for resolution and prevention of recurrence 2, 3

Remember that erythema nodosum is generally self-limited, but appropriate antibiotic therapy for the underlying streptococcal infection is crucial to prevent complications and recurrence.