Your scalp itches and on top of that, small white flakes escape from your hair and settle on your clothes? It is definitely dandruff. Today, let's look at the origin of dandruff and the reasons for its appearance in the scalp .
The origin of dandruff
Dandruff is actually bits of skin , called " dander ", that take the shape of tiny snowflakes . By definition, scales are thin strips of skin that detach from the epidermis .
This phenomenon is caused by an acceleration of the epidermal cell cycle . In general, the scalp cell cycle lasts about 28 days. In some people, this cycle can last much shorter, and the dead cells, expelled prematurely by the new cells, intertwine and form scales, which are therefore dandruff.
The different types of dandruff
Indeed, there are several types of dandruff: dry dandruff and oily dandruff .
- Dry dandruff : white, thin and flat, they form on dry hair and are easily visible. Dry dandruff is easily detached and falls off the scalp, and its presence is often associated with itching.
- Oily dandruff : yellowish, oily and round, they form on oily hair and are more visible than dry dandruff. Unlike dry dandruff, oily dandruff stays in the scalp and is more difficult to remove. They are generally caused by excessive secretion of sebum.
Why do we have them?
First of all, know that having dandruff is not synonymous with poor hygiene. Thus, we can justify the appearance of scales during infectious diseases, chronic genetic diseases but also in the event of aggressions of the skin ( sunburns , irritations or burns).
Although the mechanism responsible for the appearance of dandruff is known, the origin of the disruption of the cell cycle remains to this day still unknown. Dermatologists speak more often of risk factors than of causes. Among these factors are:
- Certain skin infections (seborrheic dermatitis or psoriasis);
- A genus of yeast called Malassezia ;
- Untimely scratching in case of itching on the scalp;
- Tiredness ;
- Stress ;
- Smoking ;
- Poor diet and poor sleep cycle ;
- A hormonal disorder .
Anyway, it is a natural elimination of superficial cells. Dandruff is therefore neither dangerous nor worrying.