Best Once-Weekly Treatment for Moderate-to-Severe Scalp Psoriasis
For an adult with moderate-to-severe scalp psoriasis requiring once-weekly systemic therapy, etanercept 50 mg subcutaneous once weekly is the recommended treatment after a 12-week induction period of 50 mg twice weekly. 1
Primary Recommendation: Etanercept
The American Academy of Dermatology provides a Grade A recommendation (highest strength) for etanercept as monotherapy specifically for moderate-to-severe plaque psoriasis affecting the scalp. 1 The dosing algorithm is:
- Induction phase: 50 mg subcutaneous twice weekly for 12 consecutive weeks 1
- Maintenance phase: 50 mg once weekly thereafter 1
This is the only biologic with both a once-weekly maintenance dosing schedule and a specific Grade A recommendation for scalp psoriasis in the AAD-NPF guidelines. 1
Evidence Supporting Etanercept for Scalp Psoriasis
A randomized, double-blind, placebo-controlled trial demonstrated that etanercept 50 mg twice weekly achieved 86.8% mean improvement in Psoriasis Scalp Severity Index (PSSI) at 12 weeks compared to 20.4% with placebo (P < 0.0001). 2 Importantly, 86% of etanercept-treated patients achieved PSSI 75 (≥75% improvement) versus only 11% with placebo. 2 When transitioned to once-weekly maintenance dosing, the response was sustained with 90.6% mean PSSI improvement at week 24. 2
Why Not Other Biologics?
While other biologics may have superior efficacy for body psoriasis, they do not meet the once-weekly dosing requirement:
- Adalimumab: Dosed every 2 weeks (40 mg subcutaneous), not once weekly 3
- Ustekinumab: Dosed every 12 weeks after initial loading, not weekly 1
- Secukinumab: Dosed every 4 weeks after loading, not weekly 1
- Ixekizumab: Dosed every 4 weeks (or every 2 weeks for some patients) after loading, not weekly 1
- Risankizumab: Dosed every 12 weeks after loading, not weekly 4
Augmenting Efficacy with Combination Therapy
The AAD provides a Grade A recommendation to combine etanercept with high-potency topical corticosteroids with or without vitamin D analogues to augment efficacy for scalp psoriasis. 1 This combination approach addresses both systemic inflammation and local scalp disease, and is particularly important during the initial 12 weeks of therapy. 1
Clinical Considerations
Important caveat: The 50 mg once-weekly maintenance dose is less efficacious than continuing 50 mg twice weekly. 1 Some patients may require the higher twice-weekly dose for optimal disease control. 1 However, if once-weekly dosing is specifically required (for compliance, cost, or patient preference), etanercept remains the only biologic option that can be administered on this schedule. 1
The British Association of Dermatologists notes that treatment response should be assessed at 12 weeks, with continuation only in patients achieving adequate response. 1 Treatment can be discontinued without risk of disease rebound, though response rates may be lower upon retreatment. 1
Common pitfall to avoid: Do not use systemic corticosteroids (oral prednisone) for scalp psoriasis, as the AAD explicitly recommends against this due to poor long-term efficacy and risk of rebound flares. 3, 5