Not all dandruff is created equal. In truth, flaking of the scalp and other hairy areas has a wide variety of factors at blame. The syndrome seems to be a response to a variety of imbalances: too little moisture, improper nutrition, cosmetic and hair care products, and emotional strain. However, the chief cause seems to be the uncontrolled growth of a fungal infection which was once called pitysporum, but is now known as Malassezia.
As in many other yeast-like maladies, Malassezia normally occurs on healthy heads, as well those afflicted by symptoms. As a lipophile, or fat-eater, Malassezia feeds on follicle oils when they are produced in excess. This in turn leads to both drying of the scalp and greasiness, as the hair glands produce even more oil to moisturize the scalp, only to have Malassezia consume it and grow. This rapidly becomes a vicious cycle causing unremitting dandruff and seborrhea.
Skin cells have a brief life cycle, surviving only 20-30 days from the moment of creation in the dermis. New cells are constantly replenished from below as older ones expire and produce the outer layers of the epidermis. Eventually, the skin breaks off onto shower towels and hairbrushes, barely noticeable because the process is so gradual.
When the balance is upset, however, Malassezia takes over, and the skin cells die much more quickly, often in under two weeks, causing flaking of the scalp. The dandruff particles are composed of these dead fragments of skin, glued together by globs of hair oil.
Researchers have not singled out a culprit for the syndrome, but it seems that Malassezia outbreaks are stimulated by environmental factors as well as endocrine imbalances, overproduction of oil glands, immune disorders, genetic predispositions, and complications of certain neurological disorders such as Parkinson’s, can all contribute to an overgrowth and the signs of dandruff.
Who is Susceptible?
Almost any grown person could be at risk for scalp disorders, but some demographics are more prone than others. Males between adolescence and middle age are the primary sufferers of Malassezia-related dandruff and other symptoms, chiefly due to the greater size of sebaceous oil glands, in this group. Considerable evidence connects the syndrome to the hormone testosterone, which appears in both genders at puberty, but in greater amounts in males.
As mentioned earlier, oily hair promotes growth of the Malassezia, so infrequent showering is definitely a factor. More mysterious is the connection with nerve diseases and stress disorders, but it seems that several types of conditions which compromise the immune system can create an imbalance. Among these are HIV/AIDS, heart attacks and strokes, as well as the aforementioned neurological dysfunctions.