Not having a hair on the stone is called in other words being bald, either because we have lost our hair or because we have shaved it. The maintenance of the skull is not quite the same in both cases but the common points explain the explosion of specialized products to care for and maintain “disheveled” leather.

The scalp refers to the part of the skin of the skull that develops hair-like hair. To make a hair or a hair, it’s the same recipe: you need a hair follicle or pilosebaceous, a small segment of the epidermis (superficial layer of the skin) invaginated in the dermis (2nd layer of the skin). Each follicle has a bulb at its base and is nourished by a papilla. The bulb is the invisible part of the hair and measures 4 mm.

Note for the anecdote that the hair grows indefinitely while the hair stops its growth once the maximum length has been reached. The sebaceous glands present in the dermis are connected to the follicles by excretory ducts which allow the secreted sebum to spread along the hair or hair to lubricate it. This sebum is important for understanding the bald head. But first, we must distinguish two types of bald skulls: the involuntary and the voluntary.

The involuntary bald head is called baldness. 6,5 million men worldwide are affected by it: hair loss is progressive. We are talking about androgenetic baldness, oddly enough in both men and women. When only certain areas of the skull (for example the temples) are affected, it is called alopecia.

Every day we lose 45 to 100 hairs and when we go bald we have lost 100 to 000 hairs. The pilosebaceous follicle (back to this) is programmed to perform 150 to 000 cycles throughout life. The hair cycle includes 25 phases:

• The hair grows for 2 to 6 years;
• There is a transition phase for 3 weeks;
• Then a rest phase for 2 to 3 months;
• Then the hair falls out.

In the event of baldness, the cycles accelerate.

Quite different are the problems of shaved heads. Historically, men but also women shave their hair or are shaved. It is about showing a religious affiliation, to pose an act of rebellion, to mark a punishment, to adhere to a fashion, to take an aesthetic position or to show creativity or freedom. “I do what I want including my hair.”

On a shaved head, you can still see the hairline, but the skin tends to dry out. It should be moisturized with a special oil or cream. Better to entrust the shaving to a professional. The trimmer does less damage than the razor. Cuts caused by blades take a long time to heal and sometimes require the local application of an antiseptic or antibiotic cream.

Just because we no longer have hair doesn’t mean we don’t use shampoo to wash our scalps. The shampoo is a syndet (from the English synthetic detergent) which does not contain soap but synthetic surfactants; its pH is therefore adjustable, it foams a lot and its rinsability is better: no deposits after use.

Its origin is worth telling: during World War II, the Americans invented this product so that their soldiers could wash themselves in seawater with foam. Soap does not foam in seawater.

There are a large number of specialist care lines for shaved heads. We even see it recently in advertising.

In the absence of hair, the bald head loses its thermal protection. It is advisable to wear a hat or cap in winter. A sort of icing on the cake, this accessory that invites you to boost your creativity completes a very personalized look. It is also necessary to widely use a high sun protection cream in summer. One does not exclude the other from the rest. It remains to be understood why the term “leather” is used for this piece of skin since it usually refers to the skin of a dead animal. But this reflection goes far beyond the subject …