Dandruff itself isn’t a fungus; however it is caused by the presence of Malassezia globosa, a naturally occurring fungus. This fungus is present on everyone’s scalp and breaks down oils known as sebum; a by-product of this reaction is oleic acid.
It is estimated that one in two people globally are sensitive to oleic acid, the scalp reacts by becoming irritated and increasing the skin cell renewal rate, which then shed in the form of white flakes.