Treatment of Perianal Streptococcal Infection in Children
For a child with perianal streptococcal infection, prescribe oral amoxicillin 50 mg/kg/day divided twice daily (maximum 1000 mg/day) for 10 days, or alternatively penicillin V 250 mg twice or three times daily for 10 days. 1
First-Line Antibiotic Options
Preferred regimens based on IDSA guidelines for Group A Streptococcal infections include: 1
Amoxicillin: 50 mg/kg once daily (maximum 1000 mg) for 10 days 1, 2
Penicillin V: Children 250 mg two or three times daily for 10 days 1
- Adolescents: 250 mg four times daily or 500 mg twice daily 1
Benzathine penicillin G (intramuscular): Single dose of 600,000 units if weight <27 kg (60 lbs), or 1,200,000 units if ≥27 kg 1
- Consider this option if compliance with oral therapy is questionable 1
Penicillin-Allergic Patients
For children with documented penicillin allergy: 1
Cephalexin (first-generation cephalosporin): 20 mg/kg per dose twice daily (maximum 500 mg per dose) for 10 days 1
- Avoid in patients with immediate hypersensitivity reactions to penicillin 1
Cefadroxil: 30 mg/kg once daily (maximum 1 g) for 10 days 1
Clindamycin: 7 mg/kg per dose three times daily (maximum 300 mg per dose) for 10 days 1
Azithromycin: 12 mg/kg once daily (maximum 500 mg) for 5 days 1
Clarithromycin: 7.5 mg/kg per dose twice daily (maximum 250 mg per dose) for 10 days 1
Critical Treatment Duration Considerations
Treatment must be at least 10 days to prevent acute rheumatic fever, regardless of clinical improvement. 1, 2 However, for perianal streptococcal dermatitis specifically, 14 to 21 days of treatment is recommended based on clinical experience with this condition. 3, 4
- The longer duration (14-21 days) is supported by research showing that perianal streptococcal infections have a 20% recurrence rate within 3.5 months, and extended treatment may reduce this risk 5
- Clinical and microbiological cure should guide final treatment duration 3
Adjunctive Topical Therapy
Consider adding topical mupirocin 2% ointment to the perianal area to augment systemic therapy, though systemic antibiotics remain the primary treatment. 3, 4, 6
Important Clinical Pearls and Monitoring
Post-treatment monitoring is essential: 3, 4
- Obtain post-treatment perianal swabs to confirm microbiological cure 3, 4
- Perform urinalysis to monitor for post-streptococcal glomerulonephritis 3, 4
- Clinical examination should confirm resolution of the sharply demarcated perianal erythema 5
Screen for concurrent pharyngeal carriage: 5
- Approximately 63% of children with perianal streptococcal infection have asymptomatic Group A Streptococcal throat carriage 5
- Consider obtaining a throat swab even if the child is asymptomatic for pharyngitis 4, 5
- Treating throat carriage may prevent recurrence through digital inoculation from nasopharynx to anus 5
Common Pitfalls to Avoid
Do not use topical corticosteroids, as this is a bacterial infection requiring antimicrobial therapy, not an inflammatory dermatosis. 3, 5
Do not stop treatment early even if symptoms improve rapidly—the full 10-day minimum (preferably 14-21 days for perianal disease) is necessary to prevent complications and recurrence. 1, 3
Do not use sulfonamides or tetracyclines, as Group A Streptococcus frequently demonstrates resistance to these agents. 1
Recognize that diagnosis is often delayed (≥3 weeks in 65% of cases), as perianal streptococcal dermatitis is frequently misdiagnosed as other conditions such as candidiasis, pinworms, or inflammatory bowel disease. 5, 6
Recurrent Infections
If the child experiences recurrent perianal streptococcal infections despite appropriate initial treatment: 1
Clindamycin: 20-30 mg/kg/day in three divided doses (maximum 300 mg per dose) for 10 days 1
Amoxicillin-clavulanate: 40 mg/kg/day (amoxicillin component) in three divided doses for 10 days 1
Benzathine penicillin G with rifampin: Single IM dose of benzathine penicillin G (dosing as above) plus rifampin 20 mg/kg/day in two divided doses (maximum 600 mg/day) for 4 days 1