Hair Patterns

Hair grows in patterns or 'streams': this is the typical clockwise stream.Knowledge of hair streams is important in styling

HAIR FACTS

Effects of damage on hair growth Damage to the skin starts up a new growing phase in resting follicles. Wounds cause hair growth in the skin around them, provided there is no scarring in the follicle. It is not true that cutting your hair makes it grow faster or thicker. Nor does shaving your legs make the hair grow coarser - it just feels that way. The width of the hair shaft is determined by your genes, and is not affected by anything you do to your skin or to the hair shaft itself. Effects of chemotherapy on hair patterns Treatment of cancer with drugs may cause apparent complete hair loss. This is because these drugs are designed to kill cancer cells, which are cells that are growing out of control. Other cells that are growing very actively may be affected too: these may include cells in the bowel lining and also in hair follicles. This leads to a 'break' in growth and an inherent weakness. Once the drugs are stopped the patient's hair starts to grow back, but when it reaches the surface it tends to break. This is what causes the apparent hair loss. The hair that subsequently grows may may look quite different from the old. This is because the growth patterns of the sensitive cells of the hair bulb may still be upset by the effects of the drug.

Hair streams

A hair does not grow straight up out of the skin, but leaves the follicle at a definite and predetermined angle. This angle determines the direction along which the hair will lie, and determines the patterns or streams that the hairs make on the head. Often the streams spiral outwards from a central point (or points) on the crown of the head. Usually these spirals, or 'whorls', run in a clockwise direction.

A characteristic clockwise whorl of hair, with an element of unruliness

The classical 'cowlick', seen in around 7% of children, is due to a particular hair stream on the forehead.

Unruly hair in children may be the result of scalp hair patterning. Another possible reason is an unusual structure of the hair shaft.

A boy with 'cowlick' hair

Hairlines

Forehead hairlines are determined genetically. The hairline that you were born with may well be the one you ultimately have in your adult life. Nearly all women keep their frontal line unchanged from childhood to old age, although some women's hairlines may seem to recede because their hair gets thinner. About half of all men may expect the hairline to recede to some extent, however.

A light forehead (genetically determined)

The decline in density of a woman's hair through the decades: the stages numbered D5 and D6 are normal for a woman in her eighties, but would be quite abnormal for someone in her twenties or thirties [reproduced by permission of Dr. R. Dawber]

Examining hair

From time to time doctors, scientists, hair stylists and technicians are all asked, for different reasons, to examine someone's hair. All of them need to know the right methods to use, and to understand the hair growth cycle and the cosmetic treatments and weathering processes that affect the hair's appearance.

Examining hair: a gentle pull on the hair can indicate the extent to which hairs are being shed  

Correct examination of hair, whether in the doctor's surgery (above) or in the salon, is important in understanding its medical or cosmetic condition; this lady's hair is a challenge to the stylist if not to the doctor

Loose hairs

Many people worry because they often find loose hairs on their clothes, or after shampooing, and they become terrified in case they may lose some or most of their hair.

If you pull the hair lightly with your hand, you may well find that a few hairs do come out. These are almost certainly hairs that are ready to fall anyway - telogen hairs. You can confirm this by looking at the roots in a good light. A telogen follicle root is a little hard, white bead. Brushed-out hairs all have this kind of root.

A normal telogen hair with a hard 'club' end, seen under a light microscope and an electron microscope

On the other hand, the root of a hair that is pulled out is fat, soft to the touch and sticky - it will stick to your hand, because it still carries fluid from the follicle. And pulling it out hurts! This is an anagen hair, one which was not ready to be shed.

An anagen hair that has been plucked out: notice the soft, sticky tail

HAIR FACTS

Shampooing and hair loss Telogen hairs fall out very easily. As catagen hairs change to telogen, the tails are slowly reabsorbed into the follicle. The roots of hairs in these early stages of telogen may be pulled out before they are quite ready to come out, especially if the hair is shampooed more energetically than usual. This is why, whenever there is a change in the shampooing or conditioning regime, or a move to new brushes, loose hairs are often found for two or three days after the change. People often blame a new shampoo or conditioner, claiming in horror, 'I put this product on my head and now I'm losing my hair'. The loose hairs are nothing to do with the product: the condition will settle down in a day or two, once these hairs have been shed. In normal circumstances, when you find loose hair in the plug-hole after shampooing the new hair is already re-growing.

 

 

 

 

 

 

 

 

 

 

 

 

Closer examination

Hair stylists and technicians examine the whole head of hair as part of their everyday practice. Matters to note include racial type, hair length and hair thickness, and if there is evidence of weathering, of previous cosmetic treatments such as perming and tinting and of accumulated hair spray.

A closer examination of the roots under a good light usually indicates the real state of the hair. The first centimetre or two of growth may look very different from the rest. This could indicate a change in the treatment that the hair has received, perhaps to a persistently harsh regime.

Next comes a look at the individual hair shafts with the naked eye. This may not reveal much, unless there is unusually serious damage. In very long hair that has weathered, the end may look a different color from the rest, or perhaps less glossy. This is almost certainly the onset of split ends.

Examination of this beautiful hair showed little or no damage until the last few centimeters; this is because it has never been processed

Under the microscope, however, a very different picture may emerge. Hair scientists use both ordinary microscopes and electron microscopes to examine hair in the laboratory. These allow them to understand what happens to hair when it is heated, permed, tinted and so forth. You will find examples of what can be seen under both kinds of microscope throughout this book.

A hair scientist's laboratory: the electron microscope

A hair, carrying some normal fragments of debris, seen under the electron microscope