What is the first-line treatment for plaque psoriasis covering less than 10% of the body when moisturizer is not effective?

First-Line Treatment for Plaque Psoriasis Covering Less Than 10% of Body Surface Area

For plaque psoriasis covering less than 10% of the body surface area where moisturizers have failed, topical corticosteroids are the recommended first-line treatment due to their rapid efficacy and favorable safety profile. 1, 2

Treatment Algorithm

First-Line Options:

1. Topical Corticosteroids

   • Start with a moderate potency (class III-IV) corticosteroid for the body 1
   • Use low potency (class VI-VII) for sensitive areas (face, intertriginous areas, genitalia) 2
   • Apply once or twice daily for 2-4 weeks 2, 3
   • No unsupervised repeat prescriptions should be made 1

2. Vitamin D Analogs (alternative or combination)

   • Calcipotriene 0.005% ointment once or twice daily 4
   • Improvement typically begins after 2 weeks of therapy 4
   • After 8 weeks, approximately 57% of patients show marked improvement with once-daily application 4

Second-Line Options (if inadequate response to first-line):

1. Combination Therapy

   • Vitamin D analog + topical corticosteroid (superior to either agent alone) 1, 5
   • Sequential therapy approach:
     • Clearance phase: potent corticosteroid
     • Transition phase: alternating treatments
     • Maintenance phase: vitamin D analog 6

2. Coal Tar Preparations

   • Start with concentrations of 0.5-1.0% crude coal tar in petroleum jelly
   • Increase concentration gradually to a maximum of 10% 1

3. Topical Dithranol (Anthralin)

   • Start at 0.1-0.25% concentration
   • Increase in doubling concentrations as tolerated
   • Can be used in "short contact mode" (15-45 minutes daily) 1

Clinical Considerations

Advantages of Topical Corticosteroids:

• Rapid onset of action (improvement within 1-2 weeks) 7
• Simple to use and relatively inexpensive 7
• Lower incidence of local adverse events compared to vitamin D analogs 8

Advantages of Vitamin D Analogs:

• Better maintenance of therapeutic effect after discontinuation 1
• Lower risk of skin atrophy with long-term use 8
• Effective in 6-8 weeks of treatment 7

Important Caveats:

• Limit use of potent corticosteroids to 4 weeks to minimize risk of skin atrophy 2
• For sensitive areas (face, intertriginous areas), use low-potency steroids or calcineurin inhibitors 1, 2
• Regular clinical review is essential when using corticosteroids 1
• Periods of alternative treatment should be employed throughout the year 1
• For long-term management, consider rotation or sequential therapy to minimize side effects 6

Monitoring:

• Evaluate treatment response after 4 weeks 2
• Monitor for local adverse effects:
  • Corticosteroids: skin atrophy, telangiectasia, striae
  • Vitamin D analogs: irritation, burning sensation
• If inadequate response after 4-8 weeks, consider adding phototherapy or switching to another topical agent 2

The evidence strongly supports topical corticosteroids as the most effective first-line treatment for limited plaque psoriasis, with vitamin D analogs as an excellent alternative or complementary therapy. The combination of both agents provides superior efficacy with a better safety profile than either agent used alone 5.