As we saw in Chapter 1, all hairs naturally fall out at the end of the growing period. Everyone loses between 50 and 80 hairs a day. They tend to come out with brushing and shampooing. So if you wash your hair only once a week, it is perfectly in order for you to lose several hundred hairs at one go!
Sometimes, however, a person may start to lose more hairs than usual. If this hair loss is significant, and if it persists, then sooner or later the scalp may become visible through the thinning hair. The condition is called alopecia. The name comes from the Greek word alopekia, which means 'fox': foxes (and also dogs) sometimes suffer from bald patches due to an unpleasant disease called mange. (Fortunately, humans do not get mange!)
The commonest kind of hair loss is simple baldness. Many people find this type of baldness embarrassing and distressing, but it is not a disease - it is a perfectly normal event. For thousands of years, however, it has caused concern and anxiety, and people have sought remedies and 'cures' without number, in spite of some of them being uncomfortable and even painful.
Baldness affects both men and women. It is much more obvious in men, however. By the age of 25, 25% of men have lost some of their hair, and the proportion rises to 50% by the age of 50. Many men accept, however reluctantly and vainly hoping that it may not be so, that they are likely to go partly or completely bald if their fathers have done so. They are right, in that baldness is genetically determined in both men and women. In women, however, baldness is not only unexpected, particularly in the twenties and thirties let alone later, but understandably unacceptable.
In men, baldness usually begins at the temples, above the forehead and at the crown of the head. In these areas the hair follicles of sufferers are genetically pre-programmed to revert from producing terminal hairs to producing vellus-like hairs. The growth phase of the hair (anagen) becomes shorter and shorter, with a greater proportion of hairs in the shedding (telogen) phase.
This change happens under the influence of male hormones (androgens) and can begin as early as the time of puberty or soon after, when androgen production in the body reaches a peak. Scientists call this kind of baldness androgenetic alopecia (meaning 'baldness due to androgens'). The eunuchs who served the harems of the east in days gone by never went bald!
Most women who come to dermatologists with hair thinning have androgenetic alopecia too. Baldness in women usually starts ten years or so later than in men, however. Fortunately for the sufferers, the amount of loss in women is differently distributed and less dramatic. The hairline usually remains intact and there is little or no loss at the temples.
The patterns of baldness thus differ between men and women. Hair scientists speak of male pattern baldness and female pattern baldness. Occasionally, though rarely, women suffer from male pattern baldness and men from female pattern baldness.
Progressive hair loss in Hamilton-type male pattern balding: (top) from the crown of the head, (centre) from the mid area, ( bottom) from the forehead and temples
The Ludwig pattern of hair loss, which is most common in women
The typical Ludwig pattern of baldness, seen here in a young woman.
Extreme Ludwig pattern hair loss in a elderly lady
Female pattern balding: in spite of extensive hair loss, this lady has (just) retained her original hairline
Apes suffer with alopecia too!
Humans are not the only primates in which baldness happens naturally at sexual maturity. Many orangutans and chimpanzees of both sexes show some signs of baldness when they reach maturity.
Treatment for baldness
No one has yet achieved that longed-for prize so desperately sought, a certain cure for baldness.
A drug called Minoxadil is now available over the counter, or on private prescription, in the UK and in many other countries. The drug is applied to the scalp twice a day, but no guarantee of its effectiveness is offered. According to various experts it may at best stop the hair loss in about 80% of users; 30% will see some downy growth after three or four months or use, and a lucky 30% will see some visible re-growth of hair. It must be remembered that it has to be used continuously, for the rest of the user's life.
In the view of experts, most other so-called treatments are a waste of time and money. A great deal of research into the subject is going on, and other treatments may become available in the near future.
Diffuse hair loss
The second most common cause of hair loss is the general, or so-called diffuse, hair loss. In this condition the hair is shed from all parts of the scalp. A great deal of hair has to be lost before the effects become visible, however. The hair may fall during either the growing (anagen) or the resting (telogen) phase.
A sudden diffuse loss of hair may be both dramatic and distressing. One well-known cause of the loss of large amounts of hair is the drugs that are taken during cancer treatment, and in this case the hair is lost while it is in the growing phase. Fortunately the hair re-grows when the treatment is stopped.
Often women have some diffuse hair loss after the birth of a baby. During a pregnancy hair tends to grow well and to look healthy, under the influence of high levels of female hormones. It may in fact stay in the anagen phase throughout the pregnancy. When the baby is born this stimulation stops, and many of the follicles enter the catagen stage. Soon afterwards they enter the telogen phase in the normal course of events. They will be lost some two or three months later as the new hairs start to grow again. This is called telogen effluvium.
Two cases of telogen effluvium: the young woman above had a baby three months ago ...
... while this lady's condition is due to iron deficiency
The amount of hair shed naturally by one person over one year
One day's natural hair loss
The sudden patchy loss of hairs may be due to a condition called alopecia areata. The condition can be recognised by examining the shed hairs under the microscope: in alopecia areata these look like exclamation marks. The sufferer may be only mildly affected, with thinning patches on the scalp, but occasionally the disorder becomes so widespread and severe that all the body hair is lost.
Classical alopecia areata, showing an isolated patch of almost complete hair loss
No one knows what causes alopecia areata. It usually disappears without treatment. Steroid injections given by a doctor may help in persistent cases of localised alopecia areata.
Acute and severe alopecia areata, in which hair over large areas may fall off at a touch
Acute alopecia areata in a young boy
Alopecia totails, a condition in which all the body's hairs are affected and the sufferer become completely hairless
A typical case of alopecia areata seen in the salon
People with the condition called trichotillomania feel compelled to pull out their hair. The effects are seen on both the scalp and the upper eyelids. In the affected areas there are hairs of different lengths. When looked at under the microscope they show fractures.
Typical cases of trichotillomania, due to repeated pulling out of hairs: the new hairs grow at different rates and therefore different lengths, as can be felt when the scalp is touched
The effect of braiding, leading to traction hair loss
Hair loss due to traction and cosmetic abuse
Hair loss in children
We have already looked at several conditions which can lead to hair loss in children. Often an area of hair loss is seen at the age of two or three months, and this is quite normal. Sometimes the development of mosaic patterns of hair growth leads to apparent hair loss. Alopecia areata and trichotillomania are both seen from time to time in children.
In addition some children have a condition called loose anagen syndrome, in which the hair can be easily and painlessly pulled out. It is most common in fair-haired girls. It tends to improve as they grow older.
The condition known as trichothiodystrophy, which is a sulphur deficiency
The pictures above illustrate a type of hair malformation known as trichorrhexis invaginata
Cheveux incoiffables (literally,'uncombable hair'): the hair shafts are congenitally abnormal and the hair stands straight up; it is vulnerable to damage and may break
An abnormally shaped hair shaft associated with the condition known as cheveux incoiffables
Two more examples of the congenital condition known as cheveux incoiffables
Woolly naevus is another congenital hair condition