Patterned hair loss is a progressive hair loss that occurs in a specific pattern. The pattern in men is different to the pattern in women. Men develop recession at the temples, thinning and eventually a bald spot on the top of the head (vertex scalp), then ultimately total baldness over the entire crown. Hair above the ears and at the back of the head is relatively spared.
In contrast, women develop diffuse thinning over the entire scalp that is most pronounced over the crown. Baldness is only seen in a minority of women (less than five per cent).
Patterned baldness is the most common cause of hair loss in both men and women, and is the result of genetic and hormonal factors. Hereditary baldness is so common that it is considered to be a normal part of the ageing process.
All men and women will be affected by patterned hair loss at some stage in their lives. While the majority of men have developed temporal recession by their mid 20s and noticeable balding by their mid 50s, for most women, hair loss is mild and only occurs later in life. However, when hair loss is premature or severe, it can cause distress. A range of treatments is available to slow or reduce hair loss, and stimulate partial regrowth
How hair grows
The human body is completely covered with hair follicles, except on the palms of the hands, soles of the feet and lips. Most follicles are tiny, and many of the hairs they produce do not grow long enough to emerge out from the pore.
Hair is made from a protein called keratin. The only living part of the hair is the root (sometimes known as the bulb), which is attached to the base of the follicle. The follicle supplies oxygen and nutrients to the root, and lubricates the hair shaft with an oily substance called sebum.
Hair is in a constant cycle of growth, rest and renewal. On the scalp, there are approximately 100,000 hair follicles. Over the course of three years, every one of these follicles will produce a hair that grows, rests, falls out and then regrows. That means that every 1,000 days, you shed 100,000 hairs. This equates to 100 hairs shed every day.
As long as the new hair that grows from that follicle is the same as the one it replaces, the hair density will remain constant. In patterned hair loss, hormones affect the follicle, making it smaller and the new hair becomes shorter and finer than the one it replaces. Eventually, the new hairs are so short and fine they become invisible and the scalp becomes bald.
Causes of hair loss
It is likely that several genes determine susceptibility to baldness. Some of these genes come from your mother’s side and some from your father’s side of the family. Identical twins lose hair at the same age, at the same rate and in the same pattern. This indicates that genetic factors are more important than environmental factors in causing hair loss.
Androgenetic hair loss is caused by androgen hormones (produced in different amounts by both men and women) that affect the hair follicles in people with a genetic susceptibility.
Some people think that stress, diet, wearing hats, frequent washing and drinking alcohol are causes of hair loss, but researchers have found no link between any of these activities and patterned hair loss. There is some uncertainty about smoking cigarettes and hair loss, but the evidence is not strong.
Male pattern baldness (androgenic alopecia)
While there are a number of treatments available for male pattern baldness, there is no cure. Treatments include minoxidil, and finasteride. Minoxidil lotion is available over the counter from pharmacies, but finasteride tablets are only available on prescription from your doctor. Cosmetic options include camouflage sprays, wigs and hair transplant surgery.
Hair loss in women (androgenetic alopecia)
Hair loss in women produces scattered thinning over the top of the scalp rather than a bald spot. Patterned hair loss occurs in over 55 per cent of women as they age. For most women, the hair loss is subtle, but about 20 per cent of women develop moderate or severe hair loss.
A number of treatments are available for female pattern hair loss, including topical minoxidil lotion (not recommended for pregnant or breastfeeding women), and tablets such as spironolactone, which have antiandrogen properties (they lower the levels of male hormones). These are available on prescription and require a doctor’s supervision.
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