What first‑line topical steroid is recommended for an adult with scalp psoriasis?

First-Line Topical Steroid for Adult Scalp Psoriasis

Clobetasol propionate 0.05% solution or foam applied twice daily is the recommended first-line topical corticosteroid for adult scalp psoriasis. 1

Rationale for Ultra-High Potency Steroids

• The American Academy of Dermatology provides Grade A (strongest) recommendation for topical corticosteroids as initial treatment of scalp psoriasis, with Level I evidence supporting this approach 1
• All classes of corticosteroids (1-7) can be used safely for up to 4 weeks specifically for scalp psoriasis, unlike other body sites where ultra-high potency agents are restricted 2
• The scalp's thick stratum corneum and hair coverage reduce systemic absorption risk, making ultra-high potency agents both safe and necessary for adequate drug penetration 2

Specific Product Selection

• Generic clobetasol propionate 0.05% solution is highly effective, widely available, and among the least expensive prescription options 1
• Clobetasol foam formulations (0.05%) demonstrate superior absorption compared to solutions, with better patient compliance and quality of life improvements due to minimal residue and ease of application 3, 4
• Betamethasone valerate 0.12% foam (Class 4, high potency) achieved 72% improvement versus 47% placebo in moderate-to-severe scalp psoriasis, representing a lower-potency alternative if clobetasol is contraindicated 2

Vehicle Selection for Scalp

• Solutions, foams, and shampoos are preferred vehicles for hair-bearing areas over creams or ointments 5
• Foam vehicles absorb more rapidly with greater total absorption than lotions or solutions, while providing better cosmetic acceptability 3
• Clobetasol shampoo formulations allow once-daily application with improved patient adherence 6

Treatment Duration and Safety

• Limit continuous high-potency corticosteroid use to a maximum of 4 weeks for initial treatment, with a maximum weekly dose of ≤50 grams 2, 1
• After clinical improvement, implement gradual tapering to prevent rebound 1
• For maintenance, transition to twice-weekly application of the same agent to previously affected areas, which reduces relapse rates for up to 16 weeks 2

When Initial Treatment Fails

• If inadequate response after 4 weeks of high-potency corticosteroids, add calcipotriene solution on weekdays while restricting corticosteroid use to weekends only 1
• Never combine calcipotriene with salicylic acid simultaneously—acidic pH completely inactivates calcipotriene 1
• Fixed-combination calcipotriene 0.005% plus betamethasone dipropionate 0.064% achieves 69-74% clear or almost clear status and can be used safely for up to 52 weeks 2

Common Pitfalls to Avoid

• Do not start with low-potency agents (Classes 5-7) for scalp psoriasis—these are ineffective due to inadequate penetration through the thick scalp stratum corneum 2
• Avoid cream or ointment vehicles for scalp application, as they create undesirable cosmetic effects and reduce patient adherence 4, 6
• Do not mistake poor adherence for tachyphylaxis—a 12-week study found no evidence of glucocorticoid receptor down-regulation with continuous use; apparent treatment failure is typically due to non-compliance rather than pharmacologic tolerance 2
• Calcipotriene monotherapy is less cost-effective than clobetasol, achieving only 60% marked improvement versus 85% with clobetasol 1