Scalp psoriasis: synergy between the Malassezia yeasts and skin irritation due to calcipotriol.

To investigate if there is a synergy between the presence of the Malassezia yeasts and the adverse reaction during treatment of scalp psoriasis with calcipotriol scalp solution, patients were treated with itraconazole to reduce the number of Malassezia yeasts. This study was a double-blind, placebo-controlled parallel group study between oral itraconazole or placebo for 8 weeks in patients with scalp psoriasis. After 2 weeks, calcipotriol scalp solution was applied twice daily for 6 weeks.