WOMEN’S BODIES: HIRSUTISM

Posted on Thursday, March 12th, 2009 at 8:40 am

The belief that they have too much facial and body hair is a distressing problem for many women. They may fear that they be a hormonal imbalance and become depressed and withdrawn, believing that their appearance is flawed by excessive hair. But how much is too much? This perception depends on your inherited background and where you live.

In our society the image of female beauty promoted by fashion, advertising and the media makes facial or body hair on women a disfiguring blemish. We go to all kinds of trouble to remove it even from sites such as our legs and armpits, where it is normal and inevitable that hair will grow. In other societies, where the majority of women have a genetic tendency to grow more and darker (and thus more noticeable) facial and body hair, moderate female hairiness is quite acceptable.

In the past excessive hair growth has often been considered a cosmetic rather than a medical problem. In recent years the factors that influence hair growth have become more clearly understood; most women with unwanted hair can now be helped by medical as well as cosmetic treatment.

Before discussing the problem of excessive hair, let’s look at a few facts about hair in general.

Types of hair

There are three types of hair. Lanugo hair grows prenatally and is seen mainly on premature infants – fine, darkish hairs that disappear shortly after birth. There are two types of post-natal hair: vellus and terminal. Vellus hair is fine, short and pale, and grows all over the body except on the palms and soles, around the nails and on some parts of the genitals. Terminal hair is thicker, longer, and often strongly coloured. It is seen after birth on the scalp, eyebrows and lashes.

The tiny organs, from which hairs grow, the hair follicles, lie below the surface of the skin. Hair growth is not continuous, but goes through cycles of growth and rest. At the end of the resting phase the hair falls out and a new hair begins to grow. The length of each phase of the cycle varies with the site of the hair. The growing cycle is longest in scalp hair (three years) and shortest in arm and thigh hairs (a few months), which explains why scalp hairs grow to greater length. Each follicle goes through its cycle independently of other follicles, resulting in constant slight hair loss rather than the seasonal moult that occurs in many animals.

We are all (men and women) born with the same number of hair follicles. During life various factors influence some of the vellus hair follicles to produce terminal hairs. The number and situation of follicles normally converted to terminal hairs depend on sex and other inherited factors, both racial and familial. At puberty the production of androgens (male hormones) in both sexes converts vellus hair to terminal hair in the armpits and pubic regions.

As males progress through puberty, androgens cause terminal hair growth to develop further in an orderly sequence on the upper lip, chin and cheeks, lower legs, thighs, forearms, abdomen, buttocks, chest, back, upper arms and shoulders. The amount of this hair growth is enormously variable between men: there are as many men with a sparse beard and little or no body hair as there are men with heavy beards and body hair.

Terminal hair also develops on the lower legs and forearms in the majority of women. Whether this growth is stimulated by sex hormones is uncertain, but as it tends to be proportional to the amount of terminal hair in other sites it seems probable that it occurs more in those women whose hair follicles are more sensitive to androgens.

Excessive hair growth

There are two types of excessive hair growth, hirsutism and the less common hypertrichosis.

Hirsutism refers to the androgen-stimulated growth of coarse terminal hair in women on the ‘man the abdomen and lower back and fronts of the thighs. Note that a few со hairs around the nipples are common a normal.

Hypertrichosis is excessive growth both vellus and terminal hair. It is usually not caused by hormones. The main causes
of hypertrichosis are certain drags, thyroid disorders, after inflammation of the skin and in some metabolic disorders. This sort of excess hair disappears six to twelve months after the cause is corrected. Hypertrichosis may also occur in patches, alone or associated with a mole.

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