For an adult with mild‑to‑moderate hidradenitis suppurativa and no contraindications (no tetracycline allergy, not pregnant or lactating, age >8), is doxycycline appropriate as first‑line systemic therapy, and what dosing and treatment duration should be used?

Doxycycline for Hidradenitis Suppurativa

Doxycycline 100 mg once or twice daily for 12 weeks is an appropriate first-line oral antibiotic for mild-to-moderate hidradenitis suppurativa (Hurley Stage I or mild Stage II without deep abscesses), but it should NOT be used as first-line therapy for Hurley Stage II disease with abscesses or deep inflammatory nodules, where clindamycin 300 mg plus rifampicin 300–600 mg twice daily for 10–12 weeks is markedly superior. 1

Treatment Algorithm by Disease Severity

Hurley Stage I (Isolated Nodules, No Sinus Tracts)

• Begin with topical clindamycin 1% solution or gel twice daily for 12 weeks as initial first-line therapy 1
• Combine with benzoyl peroxide wash or chlorhexidine 4% wash daily to reduce Staphylococcus aureus resistance risk 1
• If topical therapy fails or disease is more widespread, escalate to doxycycline 100 mg once or twice daily for 12 weeks 1

Hurley Stage II (Recurrent Nodules with Limited Sinus Tracts)

• Do NOT use doxycycline monotherapy for Hurley Stage II with abscesses or deep inflammatory lesions—it achieves only ~30% abscess reduction and has minimal effect on deep nodules 1
• First-line regimen: clindamycin 300 mg twice daily PLUS rifampicin 300–600 mg once or twice daily for 10–12 weeks, achieving response rates of 71–93% 1, 2
• Doxycycline may be considered only for mild Hurley Stage II without deep inflammatory lesions or abscesses 1

Hurley Stage III (Extensive Sinus Tracts and Scarring)

• Doxycycline is inadequate; initiate clindamycin-rifampicin combination while awaiting specialist evaluation for adalimumab or surgical intervention 1

Dosing and Duration

• Doxycycline 100 mg once or twice daily for 12 weeks 1, 3
• Alternative tetracycline options: tetracycline 500 mg twice daily or lymecycline 408 mg once or twice daily for 12 weeks 1
• After completing the 12-week course, implement a treatment break to evaluate need for continued therapy and reduce antimicrobial resistance risk 1

Treatment Monitoring and Reassessment (12-Week Review)

• Reassess using pain visual analogue scale (VAS), inflammatory lesion count (nodules + abscesses), number of flares in the prior month, and Dermatology Life Quality Index (DLQI) 1
• Response is defined by Hidradenitis Suppurativa Clinical Response (HiSCR): ≥50% reduction in abscess/nodule count with no increase in abscesses or draining fistulas 1
• In a prospective European cohort of 180 patients treated with tetracyclines, 40.1% achieved HiSCR at 12 weeks 4

When to Escalate Treatment

• If no clinical response after 12 weeks of doxycycline, escalate to clindamycin 300 mg twice daily plus rifampicin 300–600 mg daily for 10–12 weeks 1, 5
• If clindamycin-rifampicin fails after 12 weeks, escalate to adalimumab (160 mg week 0,80 mg week 2, then 40 mg weekly starting week 4) or refer for specialist evaluation 1
• Consider triple therapy (moxifloxacin + metronidazole + rifampin) as second/third-line treatment before biologics 5

Mandatory Adjunctive Measures (All Patients)

• Smoking cessation referral—70–75% of HS patients are smokers, and tobacco use worsens outcomes 1
• Weight management referral if BMI elevated—obesity prevalence exceeds 75% in HS patients 1
• Pain management with NSAIDs for symptomatic relief 1
• Appropriate wound dressings for draining lesions 1
• Screen for depression, anxiety, and cardiovascular risk factors (blood pressure, lipids, HbA1c) at baseline 1

Critical Pitfalls to Avoid

• Do NOT use doxycycline as first-line for Hurley Stage II with deep inflammatory lesions or abscesses—it has minimal effect on these lesions 1
• Do NOT continue doxycycline beyond 12 weeks without formal reassessment—prolonged use increases antimicrobial resistance without proven additional benefit 1
• Do NOT rely on topical clindamycin alone for Hurley Stage II—it only reduces superficial pustules, not nodules or abscesses 1
• Avoid long-term antibiotic use without treatment breaks to reduce antimicrobial resistance risk 1, 2

Evidence Quality and Limitations

• The evidence supporting doxycycline in HS is notably weak, based primarily on a single RCT comparing tetracycline to topical clindamycin, showing modest 30% abscess reduction with no significant improvement in patient-reported outcomes 1
• Doxycycline has been evaluated primarily in combination with biologics (PIONEER studies), where it showed no independent benefit 1
• A 2021 prospective study of 108 patients found tetracycline provided the greatest clinical improvement measured by Hidradenitis Suppurativa Score, with higher reduction associated with lower BMI, Hurley stage III, and higher baseline disease severity 3

Special Population Considerations

• Pediatric patients ≥8 years old: doxycycline 100 mg once or twice daily is appropriate 1
• Breastfeeding patients: limit doxycycline to ≤3 weeks without repeating courses; consider amoxicillin/clavulanic acid, erythromycin, azithromycin, or metronidazole as alternatives 1
• HIV-positive patients: doxycycline offers added prophylactic benefit against bacterial sexually transmitted infections 1