Hair, like health, is very much taken for granted. We may not miss it until we begin to lose it. Hair loss represents different things to different people. To some, it is an all too visible proclamation of the passing of youth. To others, it merely engenders the need to update the photograph in one’s travel documents. Of greater consequence, is the fact that the shedding of excessive quantities of hair may be a sign of disease. We need to know about normal hair physiology and the common causes of hair loss if we hope to preserve our health and hair.
The Hair Cycle
Hair grows out of hair follicles which appear to have a life of their own. The hair elongates during an active growing (anagen) phase. This may last for 3 to 7 years on the human scalp. Activity is followed by a transitional (catagen) phase, which lasts about 2 weeks on the scalp. The follicle then goes into a resting (telogen) phase during which the hair stops growing. Several weeks later, when the next
hair cycle begins, the follicle enters another growing phase. The old hair loses its attachment to the skin and is shed. A new hair eventually emerges from the follicle to take its place and the cycle repeats itself. Each human follicle goes through the hair cycle 10 to 20 times in a lifetime continually supplying us with new hair every few years. What comfort it is to know that a part of our ageing bodies remains forever young.
Common causes of alopecia (hair loss)
The causes of alopecia may be classified as follows:
- A disturbance of the hair follicle
- androgenetic alopecia (male or female pattern hair loss)
- alopecia areata
- A disturbance of the hair cycle
- telogen effluvium
- Physical factors
- trauma (e.g. trichotillomania [deliberate pulling of hair], prolonged pressure on the scalp)
- traction (e.g. due to hair styling)
- Skin disease
- fungal infections
- inflammatory skin diseases that result in scarring (e.g. discoid lupus erythematosus, lichen planus)
- Systemic factors or disease (factors or disease that affects the entire body)
- endocrine (hormonal) disease
- Hair shaft abnormalities
- genetic diseases
- damage by hair treatment
Androgenetic alopecia (male or female pattern hair loss)
Androgenetic alopecia is the commonest cause of hair loss in the world. Just about everyone experiences this form of hair loss to some degree in his/her lifetime after puberty. First, the bad news. The hair loss is relentless, worsens with the passage of time and incurable. The good news is that it is not, in a sense, a disease like diabetes or hypertension; it does not cause physical disability and therefore, does not require treatment, except for cosmetic reasons.
Androgenetic alopecia is due to heredity (genetic tendency) and male hormones (androgens). The hair loss becomes apparent by the early twenties in males and later in females. Normal hairs in the affected areas are replaced by progressively finer and shorter hairs until these may eventually disappear altogether.
What does androgenetic alopecia look like?
In the male, the hair loss occurs in a characteristic pattern, hence the name of the condition. It is marked by a receding hairline at the fringe in front and thinning over the crown. In the most advanced pattern, a horseshoe-shaped loss, remnant of hair remains on the scalp above the ears curling towards the back of the head.
In females, the hair loss is often first noticed at times of hormonal change, for instance, on stopping oral contraceptive pills. There is thinning of the hair over the entire top of the scalp but the hairline does not recede.
Treatment for androgenetic alopecia
The simplest way to combat androgenetic alopecia is to wear a hairpiece or a wig. Hair weaving in which a hairpiece is woven onto existing scalp hairs, may assuage fears of the toupee being inadvertently dislodged. Other options include medication and surgery.
Minoxidil solution sprayed twice daily on the affected scalp and finasteride tablets (the latter is only for males) are 2 drugs widely used for the treatment of androgenetic alopecia. They may produce some regrowth of hair or retard the balding process. Finasteride tablet compared to minoxidil solution is specific in its action against androgenetic alopecia. Finasteride is also more effective than minoxidil solution; it stops the progression of hair loss and produces hair regrowth in more than 60% of users. Both drugs are safe to use and side effects are few.
However, some people do not experience any improvement after using either of these drugs. The medication has to be used for several months before any results can be expected. And, if improvement does occur, the drug must be continued indefinitely to maintain the beneficial effects of treatment. Thus, medications for androgenetic alopecia suppress the balding process but cannot cure it.
Hair transplantation is the only permanent method of restoring hair to bald scalp. It involves the removal of skin grafts which bear hair follicle from the back of the scalp (donor site) and transplanting it to areas of the scalp where hair growth is desired (recipient site). Once transplanted, the grafts retain the growth characteristic of the donor site and continue to produce hair even as the surrounding native hairs of the recipient site continue to be lost as androgenetic alopecia progresses. In other words, hair growth from the grafts after hair transplantation is practically permanent. Although the procedure is conceptionally simple, good cosmetic results can only be achieved through careful surgical planning and close attention to detail in the execution.
In scalp reduction, an area of bald scalp is excised and the wound stitched up. This procedure reduces the area of baldness and is sometimes performed as an adjunct to hair transplantation. However, the resultant scar may be unsightly, and it may widen, therefore diminishing the final area of bald scalp removed. For these reasons, scalp reduction has lost favour among many hair surgeons.
The cause of this type of alopecia is unknown. It is believed to be due to an autoimmune process in which our very own white blood cells attack our hair follicles and damage the hair shaft. The hair fractures soon after it emerges from the scalp resulting in an area of hair loss.
Alopecia areata usually begins as a round bald patch on the scalp. It may be discovered by chance by a hairdresser or a friend as the condition does not usually produce symptoms. The hairs in the bald patch may regrow after several months or new bald patches may appear. The succession of new patches may merge with one another to produce large bald areas on the scalp. In some people, the condition may affect the entire scalp causing generalised patchy thinning or loss of all scalp hair. Hair at sites other than the scalp may be affected too, eg. the eyebrows, beard and moustache. The disease may last for months to years. While some sufferers will regrow their hair spontaneously, about a third of the cases never recover completely in spite of treatment.
Young adults with 1 or 2 small areas of hair loss may recover without treatment. Steroid injections into the bald area may accelerate regrowth. Steroids taken orally may be beneficial if the disease is very active and the patient is rapidly losing large amount of hair. Chemical agents which stimulate or divert the immune system away from hair follicles may be applied to the affected area (eg. diphencyprone) to stop the disease process and encourage regrowth. Other non-steroid oral medications to suppress the immune attack on the hair follicles can also be employed.
About 80-90% of the hair follicles in the normal adult scalp are in the anagen (growing) phase. While weathering severe physical or emotional stress, a proportion of these anagen follicles enter the telogen (resting) phase prematurely and in synchrony. After the telogen phase has run its normal course of about 3 months, the hairs are shed simultaneously. Fairly large quantities of hair may be shed daily and this development takes place 2 to 3 months after the causative event.
The events that may produce this response include surgical operations, prolonged and difficult childbirth, high fever, blood loss and ‘crash’ dieting. The severity of the hair loss depends on the duration and intensity of the stress. In severe cases, over 1000 hairs may be shed daily resulting in obvious thinning of hair over the entire scalp.
This form of alopecia does not require treatment since spontaneous and good regrowth occur after several months.
Cosmetic / Traumatic alopecia
Hairstyles in which the hair is braided, twisted or tied tightly put a great deal of strain on the hair follicle. Hairs become detached and under prolonged strain, the follicle may not recover. The result is permanent hair loss at the affected sites.
In the “pony-tail” hairstyle and the chignon when hair is pulled back and tied tightly at the back of the scalp, alopecia is seen at the hair margins especially in front.
Sikh boys who twist their long uncut hair at the top of their heads may experience hair loss over the sides and front of the head.
Afro-Caribbean hairstyles with many tight braids will in the long run result in alopecia at the margins of the braids.
Prolonged traction on the hair can result in scarring of the scalp. Hair simply does not grow from scars.
Diseases of the scalp leading to hair loss
Some of the commoner causes of scalp disease do not result in alopecia. Seborrhoeic dermatitis and psoriasis of the scalp usually cause dandruff and scalp itch. Any hair loss in these conditions is often due to vigorous scratching and picking at the scales.
In contrast, fungal infection of the scalp results in patchy loss of hair. Tinea capitis, also known as ringworm of the scalp, is more common in children than adults. It is caused by fungi that infect the skin and hair. The infected person has one or more bald, itchy, scaly and red patches on the scalp. The mainstay of treatment is oral anti-fungal therapy. Regrowth of the hair after successful early therapy is expected.
Inflammatory skin diseases such as lichen planus, morphea and discoid lupus erythematosus results in scarring of the scalp. Hair does not regrow on scars. It is thus imperative that medical attention is sought in scalp diseases and the correct treatment instituted early to limit the potential for scarring.
There are many drugs which can cause hair loss. The most common drugs associated with hair loss are those use in cancer treatment. Gradual recovery often follows discontinuation of the offending drug.
Endocrine (hormonal) disease
Hair loss can occur in disorders of resulting in abnormal hormone levels. A typical example is disorder of the thyroid gland, in which either a reduced or increased activity of the thyroid gland (hypothyroidism and hyperthyroidism, respectively) may be associated with thinning of the scalp hair. Normalizing the hormones may bring about improvement of hair loss.
Abnormalities of the hair shaft
The repeated wear and tear that normal hair is subjected to can result in abnormalities of the hair shaft. Excessive brushing, frequent blow-drying with hot air, the inappropriate use of colouring agents and chemicals for permanent waving can weaken the hair shaft and produce brittle, lusterless hair.
The causes of alopecia are numerous and varied. Many of the diseases can be cured or adequately treated to diminish hair loss. Even in incurable conditions, medical treatment may help to limit and retard the balding process.
Hair is of such profound importance to our psycho-sexual identity that unscrupulous, profìt driven individuals will not hesitate to exploit our fears of balding. The non-medical use of fancy imaging equipment to examine hair may be impressive but the promise of hair growth after expensive treatment may be an empty one. Your only defence, then, is knowledge. Knowledge empowers you to make informed choices for the management of your alopecia and you will be less vulnerable to the hard sell of the burgeoning hair industry.