UNDERSTANDING HAIR LOSS IN WOMEN

 

Foreword from Dr JJH Gilkes

 

Many women complain of increased hair loss and thinning of their hair, which often causes considerable anxiety. Therefore I welcome this information written by Dr Hugh Rushton, a leading expert in the field of nutrition and hair loss in women, which provides helpful information on a variety of female hair problems.


 

Hair loss in women is generally considered by the medical profession as neither serious, nor life threatening. However, to the sufferer it causes a great deal of distress. Often the hair loss is only apparent to the sufferer, since only they know how their hair used to be.

Understanding hair growth
To understand how changes can occur to your hair volume it is necessary to first understand the way hair grows.

Of the 100,000 to 350,000 follicles on the human scalp, not all are productive. Hair growth is cyclical and on the scalp the hair grows for around 1000 days (3 years) and then rests for a period of 100 days (3 months). This 'hair cycle' varies between individuals and is influenced by age, diet and our state of health. The old hair from the last 'hair cycle' may remain in the follicle and, if not dislodged by daily haircare procedures, it will be displaced by the new hair as it grows up the follicle. Hair length is controlled by the length of the growing phase, which is called Anagen. If you have a short growing phase of say 600 days, then the hair will grow to approximately 198mm (8 inches):- that is 600 days at 0.33mm per day of growth. With very long growth phases the hair can grow down to your feet!

Each scalp hair follicle is independent and while one hair may be growing, the next may be resting. Unlike birds and some animals, humans have no recognised moulting periods, although in those living in latitudes where wide variations in day length occur, there has been some seasonal shedding observed.

Hair shedding is quite normal

We all lose some hairs naturally each day, when we brush, comb, or shampoo. Around 50 to 150 hairs are shed each day and, while there is a wide individual variation, it is important to realise it is the change within the individual that is critical. As long as new hairs are being produced at the same rate as those falling out there will be no difference in hair density or hair shedding. But, if shedding is greater than production, hair loss ensues. For example: if an individual has been losing 50 hairs per day and this increases to 100, twice as many hairs would be observed when combing or shampooing. However, 100 hairs are still within the normal range, but for this individual it represents a worrying 100% increase and consequently noticeable hair shedding.


Hair thickness varies between individuals, with some people having finer (or thinner) hairs than others. As we grow older, there is a tendency for our hair fibres to become finer and shorter over successive cycles, but years may elapse before any obvious difference is seen.

Hair volume is determined by three factors; the number of hairs present per square centimetre, the proportion of hair growing, and hair thickness. These factors change when hair loss occurs. Almost all hair disturbances can be characterised by a change in one or any combination of these three aspects, so understanding what has changed is the key to identifying the underlying cause.

Whilst there are several causes for increased hair shedding it should be noted that 95% of hair loss complaints seen in women are caused by just two conditions. These are:-
Increased hair shedding (*chronic telogen effluvium).
Genetic hair loss (androgen-dependent alopecia).
This leaflet deals with both of these causes and mention is given to the others. Thyroid disease affects 2%; alopecia areata (hair loss in patches) 0.1%, and the scarring alopecias less than 0.01%.

*Chronic telogen effluvium relates to hair loss that has been present for longer than six months. (Acute refers to hair loss less than six months.)