What is the recommended dose of doxycycline (tetracycline antibiotic) for treating folliculitis?

Doxycycline Dosing for Folliculitis

The recommended dose of doxycycline for treating folliculitis in adults is 100 mg twice daily for 7-14 days. 1

Dosing Guidelines

Adults:

• Initial dose: 100 mg twice daily
• Duration: 7-14 days (standard course is 7 days, but may be extended based on clinical response)
• Take with food to avoid stomach upset, but avoid dairy products within 2 hours before or after taking the medication 1

Children:

• Age ≥8 years and >45 kg: 100 mg twice daily
• Age >8 years and ≤45 kg: 2.2 mg/kg twice daily
• Age ≤8 years: 2.2 mg/kg twice daily (only if benefits outweigh risks) 1

Treatment Considerations

First-line vs. Alternative Options

• Doxycycline should not be used as monotherapy for folliculitis 1
• Consider combining with topical treatments for better efficacy
• Alternative oral antibiotics if doxycycline is contraindicated:
  • Erythromycin base 500 mg four times daily for 7 days
  • Erythromycin ethylsuccinate 800 mg four times daily for 7 days 1

Special Populations

• Pregnancy: Category D - avoid use (contraindicated) 1
• Nursing mothers: Distributed into breast milk - discontinue nursing or the drug 1
• Children <8 years: Generally avoid unless benefits outweigh risks of dental staining 1

Follow-Up Recommendations

• Patients should return for evaluation if symptoms persist or recur after completing therapy 1
• If symptoms persist despite appropriate treatment:
  1. Evaluate compliance with initial regimen
  2. Consider re-exposure to infectious source
  3. Consider alternative diagnoses (e.g., gram-negative folliculitis in patients on long-term tetracyclines) 2

Important Caveats and Pitfalls

Potential Adverse Effects

• Gastrointestinal: nausea, vomiting, diarrhea
• Photosensitivity: advise patients to avoid excessive sun exposure
• Rare but serious: Stevens-Johnson syndrome, toxic epidermal necrolysis
• Potential for hand tremors (discontinue if occurs) 3

Drug Interactions

• Antacids containing aluminum, calcium, or magnesium
• Oral anticoagulants
• Iron-containing preparations
• Hormonal contraceptives (may reduce effectiveness) 1

Specific Types of Folliculitis

• For EGFR inhibitor-induced folliculitis: prophylactic doxycycline is recommended 4
• For gram-negative folliculitis (often occurring after long-term tetracycline treatment): isotretinoin may be more effective than continuing tetracyclines 2
• For laser-induced folliculitis: prophylactic doxycycline with topical steroids may be beneficial 5

Remember that appropriate diagnosis is essential before initiating treatment, and combination therapy with topical agents is often more effective than oral antibiotics alone.