What are the treatment options for psoriasis on the legs?

Treatment Options for Psoriasis on the Legs

For psoriasis on the legs, treatment should be selected based on disease severity, with topical therapies for mild disease (<5% body surface area), phototherapy for moderate disease, and systemic/biologic agents for severe disease or those with inadequate response to other treatments. 1

Assessment of Disease Severity

• Psoriasis is categorized as mild (typically <5% body surface area [BSA]) or moderate-to-severe (≥5% BSA or involvement of vulnerable areas) 1
• Even with limited BSA involvement, consider systemic or phototherapy if the patient has symptoms like pain, bleeding, or itching 1
• Quality of life impact should be factored into treatment decisions, as psychological distress can be significant regardless of physical extent 1

Treatment Algorithm for Leg Psoriasis

First-Line Treatment for Mild Psoriasis (<5% BSA)

• Topical corticosteroids are the mainstay of treatment for mild psoriasis 2, 1
  • Use moderately potent (class III) corticosteroids for leg psoriasis 3
  • Apply once daily for 2-4 weeks, then reassess 3
• Vitamin D analogs (calcipotriene) can be used alone or in combination with corticosteroids for better efficacy 3, 1
• Emollients should be used as adjunctive therapy 1-3 times daily to reduce itching, scaling, and help maintain skin barrier function 3, 4

Second-Line Treatment for Mild Psoriasis

• Low concentration coal tar preparations (starting with 0.5-1.0% crude coal tar in petroleum jelly) can be used if corticosteroids are ineffective 3, 4
• Tazarotene is indicated for stable plaque psoriasis, usually in combination with topical corticosteroids 4
• Salicylic acid can be used in combination with other topical therapies for thick plaques to increase absorption 4

Treatment for Moderate-to-Severe Psoriasis (≥5% BSA)

• Phototherapy is first-line for moderate psoriasis 2, 1

  • Narrowband UVB is the preferred option for most patients 1
  • PUVA (psoralen plus UVA) may be considered for thicker plaques 2, 1

• Traditional systemic agents are second-line options 2, 1:

  • Methotrexate (7.5-15 mg weekly) 5
  • Cyclosporine 2
  • Acitretin 2

• Biologic agents are third-line options for severe or refractory disease 2, 1:

  • TNF inhibitors (etanercept, adalimumab, infliximab) 6
  • IL-17 inhibitors (secukinumab, ixekizumab) 1
  • IL-23 inhibitors (guselkumab, risankizumab) 1
  • IL-12/23 inhibitor (ustekinumab) 1

Special Considerations

• For pregnant patients, emollients are considered safe and should be first-line treatment 1
• Avoid systemic corticosteroids in psoriasis as they can cause disease flare during taper 2
• Long-term use of potent topical corticosteroids can cause skin atrophy, striae, and telangiectasia 7
• For patients with psoriatic arthritis, consider TNF inhibitors or other biologics as first-line systemic therapy 6

Combination Strategies

• Combination therapy with topical corticosteroids plus vitamin D analogs enhances efficacy and reduces irritation 8
• Topical therapies can be effectively combined with phototherapy or systemic treatments to enhance efficacy 8
• When using combination therapy, apply vitamin D analogs after phototherapy to avoid inactivation 8

Common Pitfalls and Caveats

• Regular clinical review is essential when using topical corticosteroids 3
• No unsupervised repeat prescriptions should be provided for potent corticosteroids 3
• Incorporate periods where alternative treatments are employed into the treatment plan to minimize side effects 3
• Commercial sunbeds (emitting UVA) are rarely effective in psoriasis and may cause significant side effects; their use is not recommended 9

Treatment Algorithm Summary

1. For mild psoriasis: Start with topical corticosteroids and vitamin D analogs
2. If inadequate response: Consider combination therapy or add coal tar preparations
3. For moderate psoriasis: Add phototherapy (narrowband UVB)
4. For severe or refractory psoriasis: Progress to systemic agents (methotrexate, cyclosporine, acitretin)
5. For very severe or treatment-resistant cases: Consider biologic agents

This stepwise approach ensures optimal management of leg psoriasis while minimizing potential side effects 1, 10.