Hair combing / brushing
Combing or brushing help to remove shed skin on our scalp. It
has been suggested that inadequate combing or brushing lead to buildup of shed
skin giving rise to slightly increased risk of dandruff. However, other studies
indicated frequent combing and over shampooing could result in development of
dandruff. (Indian J Dermatol. 2010). The reason given was that frequent combing
and over shampooing affected the integrity and barrier function of the
outermost layer of the skin. This made it easier for organisms to establish
themselves and adhere to the skin.
Stress
A 2007 study found that 82 percent of patients with
depression and anxiety have excessive flaky scalp. Stress lowers our immunity
and induces the body to produce chemicals called glucocorticoids, a substance
that can calm us down. Glucocorticoids can alter the cell makeup on the scalp,
possibly leading us vulnerable to the fungus malassezia ... and the dandruff it
is often associated with.
Hormones
The sebaceous glands that produce sebum become very active
during puberty due to Hormonal changes. Sebum comprises a mixture of saturated
and unsaturated fatty acids that give our skin integrity.
In 2005, scientists from USA and Korea discovered the fungus
malassezia like to feed on saturated fatty acids in sebum. After eating up the
saturated fats, our scalp is left with too much unsaturated fats. It was
thought that excess unsaturated fatty acids together with changed structure of
skin tissues due to glucocorticoids make our scalp vulnerable to flaking and
dandruff.
Is malassezia the culprit triggering dandruff due to
increased oil production induced by hormones? Perhaps not, because etiological studies
found the prevalence rate of dandruff almost equal in pubertal and in older age
groups. At puberty, hormones induced high oil production in sebaceous glands
whereas in older people, hormonal production has tapered off and oil glands are
not as active. Yet, malassezia is prevalent in both wet and dry dandruff.
Did the conflicting opinions and evidence leave you
scratching your head in bewilderment?
In the next installment let us explore the issues of
infection, genetic factor and illness.
