Dandruff and Seborrheic Dermatitis: A Head Scratcher 404 Therapeutic Actives and Their Mechanisms of Action As there are three factors involved in dandruff etiology (Malassezia, sebum, and individual susceptibility), there are several potential avenues for treatment. One may treat the causes or one may treat the symptoms. Treating the causes would mean removal of the fungi with antifungal treatments or suppressing the secretion of sebum. Treatment of the symptoms would involve calming the inflammation with anti-inflammatory steroidal agents, minimizing cell proliferation with anti-proliferatives, or by simply grooming away the resultant flakes. Using non-medicated shampoos to simply wash away the flakes is minimally effective they are simply generated too quickly. Anti-proliferative therapies have also been poorly effective due to the minimal efficacy of available treatment materials. Sebum suppression has also proved to be very difficult, with few if any effective topical treatments available at this time. Treatment with anti-inflammatory steroidal agents can be effective in the short term but cannot be used for long-term prophylaxis due to limiting adverse effects. This leaves the most effective treatment with the most flexible options being antifungal treatment. Zinc pyrithione (ZPT) is a biocide whose rational development in the 1950s was based on aspergillic acid, the natural antibiotic from Aspergillus.75 ZPT was included in the evaluation of over 1,000 candidates for controlling the yeast of the genus Malassezia relevant in dandruff etiology. 76 ZPT has many properties which make it especially useful to deliver in the complex vehicle of a shampoo it is: • only sparingly water-soluble, allowing efficient scalp retention after rinsing • affordable for regular usage • and it allows galenic formulations due to lack of color and odor impact on product cosmetics. These attributes have led to ZPT becoming the most common material used for dandruff treatment globally. Antidandruff efficacy and safety were demonstrated in the early 1960s, which served as the