Chapter 12 395 hypotheses is steroidal anti-inflammatory agents. The effectiveness of these materials is not in conflict with the fungal hypothesis of dandruff genesis it is only intervention downstream of the original insult. Treatment options including both antifungal and anti- inflammatory agents will be discussed in the treatment section of this chapter. Using a molecular technique (terminal fragment length polymorphism) to eliminate any potential culture bias, we previously identified M. globosa and M. restricta as the predominant species present on the scalp of dandruff sufferers.44 The Malassezia yeasts are most common on sebum-rich areas of the body and degrade sebum. Specifically, the organisms contain lipases that hydrolize triglycerides, freeing specific saturated fatty acids that the yeast requires to proliferate (Figure 5). To demonstrate that Malassezia generated free fatty acids can induce dandruff like flaking in humans, we applied a marker fatty acid, in the form of oleic acid, to human scalp tissue. Even when Malassezia have been removed from the scalp, oleic acid was able to elicit a flaking response in dandruff susceptible individuals (Figure 6 and below).16 A detailed model for the metabolic pathways involved in dandruff genesis has been formally proposed (Figure 7). Malassezia globosa reside on the surface of the scalp and in the follicular Figure 6. a) Oleic acid induced dandruff-like flaking in non-dandruff human subjects b) Oleic acid induced dandruff-like flaking in dandruff sufferers