What oral antibiotic can a 17-year-old female with back and shoulder acne, unresponsive to topical benzyl peroxide and exfoliants, be prescribed?

Oral Antibiotic Treatment for Back and Shoulder Acne in a 17-Year-Old Female

Doxycycline 100 mg twice daily is the recommended oral antibiotic for a 17-year-old female with back and shoulder acne that has not responded to topical benzoyl peroxide and exfoliants. 1

Treatment Algorithm

1. First-line oral antibiotic options:

   • Doxycycline: 100 mg twice daily (preferred)
   • Minocycline: 50-100 mg twice daily (alternative)
   • Tetracycline: 500 mg twice daily (alternative)

2. Duration of therapy:

   • Limit treatment to 12 weeks when possible to prevent bacterial resistance 1, 2
   • Always combine with topical therapy

3. Mandatory combination therapy:

   • Continue benzoyl peroxide 2.5-5% to prevent antibiotic resistance 1, 2
   • Add topical retinoid if not already using 1

Rationale for Doxycycline Selection

Doxycycline is preferred for several reasons:

• Better pharmacokinetics with longer half-life than tetracycline 3
• Lower resistance rates compared to erythromycin (20% vs 50%) 3
• Fewer serious side effects compared to minocycline (which can cause rare but severe hypersensitivity reactions) 1, 3
• Effective for inflammatory back and shoulder acne that hasn't responded to topical therapy alone

Important Considerations

• Avoid monotherapy: Oral antibiotics should never be used alone due to increasing antibiotic resistance. Always combine with benzoyl peroxide to prevent resistance development 2, 3

• Side effects to monitor:

  • Photosensitivity (dose-dependent with doxycycline)
  • Gastrointestinal upset
  • Vaginal yeast infections

• Patient instructions:

  • Take with full glass of water
  • Avoid dairy products, antacids, and iron supplements within 2 hours of taking medication
  • Use sunscreen due to increased photosensitivity
  • Take at the same time each day to maintain blood levels

Follow-up and Monitoring

• Reassess after 6-8 weeks of treatment 1
• If inadequate response after 8 weeks, consider:
  1. Checking compliance with both oral and topical therapy
  2. Adding or changing topical agents
  3. Considering hormonal therapy options for female patients (spironolactone)

Common Pitfalls to Avoid

1. Using antibiotics as monotherapy: This significantly increases risk of bacterial resistance 2, 3

2. Extended antibiotic courses: Limiting treatment to 3 months reduces risk of bacterial resistance and adverse effects 2, 3

3. Inadequate topical therapy: Failure to continue benzoyl peroxide during oral antibiotic treatment significantly increases resistance risk 2

4. Overlooking hormonal factors: In female patients with persistent acne, consider hormonal therapy if standard approaches fail 1

If acne remains unresponsive after 12 weeks of appropriate combination therapy, referral to a dermatologist for consideration of isotretinoin may be warranted 1.