Lipids make up an integral part of the skin barrier, particularly for oil rich areas such as the scalp and face. The lipids on these areas play a vital role in maintaining moisture and providing a layer of defence for our most exposed areas of our skin. Some of these lipids possess (source) broad antimicrobial and antifungal abilities and disturbances of these fatty acids have been observed in atopic dermatitis (source). Even though their relation to the yeast that is believed to cause seborrheic dermatitis (malassezia) remains unclear (source), their effect on the overall microbial community of our skin's surface may present an environment more favourable to these yeast.
Some researches have identified a specific fatty acid (cis-6-hexadecenoic acid) which only appears to be present on human skin and hair, but generally not much elsewhere in nature (source). These researches noted that there was less of this unique fatty acid present on the skin of individuals affected by atopic dermatitis. A novel production process for the fatty acid was suggested through use of bacterial cultures, and its ability against malassezia was demonstrated. The biggest draw to this approach is that it makes use of the exact fatty acid that is supposed to be present on the skin in the first place, as opposed to reliance on various antifungal solutions discussed previously.
Additionally, there are studies that have demonstrated the potent anti-malassezia capabilities of organic fatty acids found elsewhere in nature. The most prominent of these appears to be caprylic acid (source). This fatty acid is most abundant in coconut and palm kernel oils, but also makes up a significant portion of the breast milk of various mammals (goats, humans, and cows). As a result, due to its potent ability to suppress various malassezia species and its natural origin, caprylic acid may hold value in the treatment of seborrheic dermatitis if properly utilized in a skin care formulation.