Hair loss and baldness

Baldness or significant hair loss is affecting people at younger and younger ages. Often linked to external factors such as stress, pollution, the appearance of bald areas can also be due to heredity or poor diet. You will have understood, the causes are multiple!

Hair loss can start before the age of 21, it affects both men and women. In France, baldness affects 10 million men and 2 million women

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Androgenetic alopecia is commonly referred to as “pattern baldness,” especially in men. In this form of hair loss, only the top of the head is affected. The hair around the skull is preserved (this is the “Hippocratic crown” of bald men).

SYMPTOMS OF ANDROGENETIC ALOPECIA IN MEN

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In men, androgenetic alopecia results in the appearance, on the top of the head, of thinner and often less pigmented hair, which becomes lighter. This baldness can uniformly affect the top of the head, or start by affecting the tip of the head (the tonsure) or the temples. Over time, the hair gradually gives way to down which in turn disappears.

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SYMPTOMS OF ANDROGENETIC ALOPECIA IN WOMEN

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Androgenetic alopecia can also be observed in women. In this case, the hair loss concerns the entire top of the head, in a diffuse manner, sometimes sparing the frontal edge (the start of the hair on the forehead). Unlike what is observed in men, androgenetic alopecia in women is never complete: hair persists, thinning.

Androgenetic alopecia can appear at any age in a woman's life, sometimes as early as puberty. It is often more marked in spring and fall. Most often, it occurs after menopause.

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IS ANDROGENETIC ALOPECIA COMMON?

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In men, androgenetic alopecia becomes more common with age. It particularly affects men of European origin. In this population, it is estimated that it affects 20% of men aged 20, 30% of men aged 30, 40% of men aged 40, and so on.

In women, androgenetic alopecia is rarer: one in five women around the age of 40, one in four women around the age of 60. However, it represents 80% of lasting hair loss problems in women.

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WHAT ARE THE CAUSES OF ANDROGENETIC ALOPECIA?

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Androgenetic alopecia results from two factors: a genetic predisposition and the action of androgens, the male sex hormones (but nevertheless present in small quantities in women).

Genes predisposing to androgenetic alopecia have been identified, one of which is carried by the X chromosome (transmitted to men from their mothers). Thus, among men, the probability of suffering from baldness is higher when it is present in the maternal family.

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In the presence of a favorable genetic background, the hair follicles on the top of the head are particularly sensitive to the action of androgens, and in particular a substance derived from testosterone (DHT, dihydrotestosterone). Under the action of this hormone, the hair growth cycle is accelerated and shortened. The hair becomes finer, less dark and falls out more quickly. The 20 to 25 growth cycles that are supposed to last a lifetime are exhausted in a few years. The hair follicles located on the sides of the skull are less sensitive to the action of the hormone and their growth cycle is less disrupted.

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In women, other hormonal factors can promote androgenetic alopecia: oral contraceptives (“pill”) or hormonal treatments for menopause. In addition, stress and excess blood cholesterol could also be risk factors for alopecia in women.

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