Scalp Psoriasis: Synergy Between the Malassezia Yeasts and Skin Irritation due to Calcipotriol
Jan Faergemann A1, Ulf Diehl A2, Louise Bergfelt A3, Astrid Brodd A3, Birgitta Edmar A4, Kjell Hersle A5, Barbro Lindemalm A5, Peter Nordin A5, Ingrid Rossman Ringdahl A1, Jørgen Serup A6
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. Altogether 137 patients, 67 in the itraconazole group and 70 in the placebo group, comprised the intention-to-treat population. There were 13 (19.4%) patients with local skin irritation in the itraconazole group compared to 33 (47.1%) in the placebo group (p<0.001). The skin irritation was significantly lower in patients with a low number of cultured Malassezia yeasts (p=0.017). Thus, when Malasessia was eliminated or the numbers reduced, the irritation produced by calcipotriol was significantly diminished.