What Is Dandruff?
Human skin cells are forever renewing themselves. As skin cells in the scalp are renewed, the old (dead) ones are pushed to the surface and then out of the scalp; they are literally expelled.
For people with dandruff, the new cells are produced at a faster rate than they die, resulting in more skin being shed, making dandruff more noticeable. If the skin is exposed to extreme temperatures, the risk of developing dandruff is greater.
Dandruff can be chronic (long-term) or the result of certain triggers. People with dandruff may also experience irritation and redness on the scalp. Excessive flaking may be caused by an underlying illness or condition, such as psoriasis, a fungal infection (Malassezia), seborrheic dermatitis, or even head lice.
Some individuals with severe dandruff may have social or self-esteem problems. Therefore, treatment may be important for both physiological and psychological reasons.
The word dandruff comes from (most likely) dand (origin unknown) and E. Anglian (England) dialect huff, hurf, meaning “scab”. This is probably linked to the Old Norse word hrufa, meaning “scab”. The Old High German word hruf means “scurf”.
A dry scalp does not cause dandruff
Some people think their dandruff is caused by their scalp being too dry. They try to deal with this by not washing their hair with shampoo, or wash it less often, believing that washing worsens the problem. This is a myth (not true). Dandruff differs from a dry scalp in that it usually gets better when you shampoo more frequently (with the right shampoos).