What is the recommended dose and treatment duration of doxycycline (DOXY) for psoriasis?

Doxycycline for Psoriasis: Dosing and Treatment Duration

Doxycycline is not recommended as a standard treatment for psoriasis based on current guidelines, as there is no evidence supporting its use for this condition in any of the major dermatology treatment guidelines.

Current Guideline Recommendations for Psoriasis

The American Academy of Dermatology (AAD) and National Psoriasis Foundation (NPF) guidelines do not mention doxycycline as a treatment option for psoriasis 1. Instead, the guidelines recommend several well-established treatments:

First-line therapies:

• Topical treatments (corticosteroids, vitamin D analogs)
• Phototherapy (narrowband UVB)

Systemic non-biologic therapies:

• Methotrexate
• Cyclosporine (2.5-5 mg/kg/day for 3-6 months)
• Acitretin

Biologic therapies:

• TNF-α inhibitors:
  • Etanercept: 50 mg twice weekly for 12 weeks, then 50 mg weekly for maintenance 1
  • Adalimumab: 80 mg initial dose, 40 mg at week 1, then 40 mg every other week 1
  • Infliximab: 5 mg/kg at weeks 0,2,6, then every 8 weeks 1
• IL-17 inhibitors
• IL-23 inhibitors

Why Doxycycline Is Not Recommended

1. Lack of evidence: None of the major psoriasis treatment guidelines (AAD-NPF, British Association of Dermatologists) include doxycycline as a treatment option.

2. Mechanism of action: Psoriasis is an immune-mediated disease characterized by T-cell activation and inflammatory cytokine production. While doxycycline has some anti-inflammatory properties, these are not specifically targeted to the pathways involved in psoriasis.

3. Potential risks: Long-term antibiotic use carries risks including:

   • Antibiotic resistance
   • Gastrointestinal side effects
   • Photosensitivity (particularly problematic as phototherapy is a common psoriasis treatment)

Alternative Approaches

If you are considering doxycycline for a patient with psoriasis, consider these possibilities:

1. Secondary bacterial infection: If the psoriatic lesions are secondarily infected, a short course of appropriate antibiotics may be warranted to treat the infection, not the psoriasis itself.

2. Comorbid conditions: Some patients may have both psoriasis and conditions that respond to doxycycline (such as rosacea or hidradenitis suppurativa).

3. Combination therapy: Some research suggests combining conventional therapies with biologics may improve outcomes 2, but doxycycline is not mentioned in these recommendations.

Conclusion

Based on current guidelines, doxycycline is not recommended for the treatment of psoriasis. Patients should be directed toward evidence-based treatments including topical therapies, phototherapy, conventional systemic agents, and biologics as appropriate for their disease severity and comorbidities.

If treating a secondary bacterial infection in psoriatic lesions, standard antibiotic dosing would apply (typically doxycycline 100mg twice daily for 7-10 days), but this would not be expected to improve the underlying psoriasis itself.