What is the treatment for perianal streptococcal (Group A beta-hemolytic streptococcus) infections?

Treatment of Perianal Streptococcal Infections

Oral penicillin or amoxicillin for 10 days is the first-line treatment for perianal streptococcal infections, with clindamycin as the preferred alternative for penicillin-allergic patients. 1

First-Line Treatment Options

For Patients Without Penicillin Allergy:

• Oral Penicillin V:

  • Children: 250 mg 2-3 times daily for 10 days
  • Adults: 250 mg 4 times daily or 500 mg twice daily for 10 days 1

• Oral Amoxicillin:

  • 40-50 mg/kg/day divided into 3 doses for 10 days (maximum 1,000 mg/day) 1, 2
  • Often preferred in young children due to better taste acceptance 3

• Intramuscular Benzathine Penicillin G (for patients unlikely to complete oral therapy):

  • Children <60 lbs (27 kg): 600,000 units as a single dose
  • Patients ≥60 lbs: 1,200,000 units as a single dose 3, 1

For Patients With Penicillin Allergy:

• Non-anaphylactic penicillin allergy:

  • Cephalexin: 20 mg/kg twice daily (maximum 500 mg per dose) for 10 days 1

• Anaphylactic penicillin allergy:

  • Clindamycin: 7 mg/kg three times daily (maximum 300 mg per dose) for 10 days 1
  • Erythromycin: 20-40 mg/kg/day divided 2-3 times daily for 10 days 3
  • Azithromycin: 12 mg/kg once daily (maximum 500 mg) for 5 days 1

Diagnostic Confirmation

• Rapid streptococcal test of the perianal area can confirm the diagnosis 2
• Routine skin culture is an alternative diagnostic method 2
• If rapid test is negative in children, a backup culture is recommended 1

Treatment Duration and Follow-Up

• A full 10-day course of antibiotics is essential to eradicate the organism and prevent complications, even if symptoms resolve earlier 1, 4
• Exception: Azithromycin can be given for 5 days 1
• Follow-up is necessary as recurrences are common, occurring in approximately 20% of cases 2, 5

Clinical Presentation and Diagnosis

Perianal streptococcal dermatitis presents with:

• Bright red, sharply demarcated perianal rash 2
• Perianal pain, itching, and sometimes blood-streaked stools 2, 5
• Most common in children between 6 months and 10 years of age 2
• Often misdiagnosed initially, with diagnosis delayed ≥3 weeks in 65% of cases 5

Important Considerations

• The condition occurs in adults more often than reported, primarily caused by Group B β-hemolytic Streptococci in adults versus Group A in children 6, 7
• Complete the full antibiotic course even if symptoms improve early to prevent recurrence 4
• Routine post-treatment testing is not recommended unless symptoms persist 1
• Testing or treating asymptomatic household contacts is not routinely recommended 1

Pitfalls to Avoid

1. Misdiagnosis: The condition is often misdiagnosed as diaper rash, candidiasis, or other dermatitis, leading to treatment delays 2, 8
2. Inadequate treatment duration: Failure to complete the full 10-day course may lead to recurrence 8
3. Overlooking the condition in adults: While more common in children, perianal streptococcal infection does occur in adults and should be considered in cases of persistent perianal erythema 6, 7
4. Failing to follow up: Given the high recurrence rate (approximately 20%), follow-up is essential 2, 5