What is pityriasis, or dandruff?

Dandruff is a widespread problem that affects most of us at some time in our lives. For some it is an embarrassing but temporary inconvenience, but for many it is a persistent problem. Dandruff is characterised by the formation of fine, white or greyish loose scales and there are variations in the severity and form of dandruff.

With some types of dandruff the flakes leave the scalp surface easily, falling onto the clothes and shoulders. In other cases the scale is more adherent to the scalp, and rather than the flakes leaving the skin’s surface, they build up to form a thick covering on the scalp.

Irritation of the scalp is a common accompaniment to dandruff, and often leads to an increase in the quantity of flakes falling onto clothing, as the scalp is scratched in an attempt to relieve the irritation.

Dandruff is caused by skin cells that divide too quickly. The epidermis, or outer protective layer of the skin, is constantly changing. The cells begin to grow from the base layer deeper in the skin and gradually move to the surface, this is called the epidermal turnover. Normally it takes approximately 28 days for the cells to move through the skin and to reach the surface. These dead skin cells are washed away when we shampoo our hair.

In cases of dandruff, the epidermal turnover is much faster than normal, with the cells taking perhaps only 12 to 15 days to accomplish their journey rather than the usual 28 or so. This proliferation of skin cells results in the formation of scale on the surface of the scalp. When this occurs there is an increase in the level of bacteria on the scalp because, with the abundance of scale, comes an improvement in their environment. The increase in the level of bacteria can then cause even more scale to form, resulting in the creation of a vicious circle.

Washing the hair and scalp with one of the many anti-dandruff shampoos that you can buy over the counter, sometimes helps in the removal of scale, but often this is a superficial and short-term answer to the solution because most of these products treat the symptom and not the cause.

Also, some of these products are so harsh and abrasive, that they can actually exacerbate the dandruff in the long term. It is the much more complex ‘underlying’ problem that must first be dealt with