Androgenetic alopecia

Androgenetic alopecia is the commonest cause of thinning hair in the world. It affects both men and women and is genetically determined. Alopecia generally affects males in the second decade of life and women in the third decade. The fact that male pattern baldness can occur in females is often overlooked by many female suffers of hair loss.

Androgenetic Alopecia in males

Under the action of male sex hormones which are called androgens the hair follicles undergo several changes which lead to alopecia.

Firstly the hair follicles undergo a shortening of the duration of the anagen phase . The hair follicles then undergo a miniaturisation of the hair follicles as the process continues the hair follicles become smaller and the hairs become shorter. This process of attack by androgens primarily affects the front of the scalp, the temporal, frontal and vertex areas (crown of the head).

The reduction in duration of the anagen phase means that more hairs will be in the telogen phase and they will be in this phase of the hair regeneration cycle for longer periods of time. As this phase does not permit growth of the hair shaft, it will result in increased hair loss and the effects will accumulate to cause baldness.

In this process, not only the size and the number of hairs decrease but hairs in the telogen phase are more likely to suffer damage and this explains why there is increased hair loss when the hair is washed. The process of androgenetic hair loss can result in a fine covering of hair that can be difficult to see as they contain little or no pigment.

To assist in the grading of hair loss and to monitor its progression several scales have been developed. Ludwig described the pattern of hair loss in females and Hamilton in males.

Male pattern baldness can occur at any age following puberty when blood androgen levels rise. The first change seen is a reduction of hair in the region of the temples. This is a very common finding and is present in approximately 96% of sexually mature Caucasian men, but not all of these individuals will go on to develop alopecia.

It is not possible to predict the extent of the eventual hair loss in any individual but in general, it is those who suffer from initial hair loss and receding hair lines in the second decade of life in whom the alopecia is likely to be the most severe.

Alopecia also does not occur with the same pattern or prevalence in all races. Oriental and North American men are more likely to preserve their frontal hair whilst African-Americans may have a lower incidence of baldness.

We should also point out that there is no truth in the belief that alopecia is a marker for Virility in men and frequent washing of hair does not cause alopecia.

The frequency of baldness is often misquoted but there is a general rule that gives a good approximation of the prevalence of alopecia in Caucasian men.

• At the age of 25 years, 25% of all men will have some obvious hair loss
• At the age of 50 years , 50% of men will have some obvious hair loss
• On average the sign of androgenetic hair loss occur in females 10 years later than in males.

Androgenetic Alopecia in females

Hair loss due to Androgenetic Alopecia is also found in women, although many women today are not aware of this fact. It is noticed later in life in females compared to males: in females androgenetic hair loss first becomes apparent in the 3 rd -5 th decade of life, whilst in men it appears in the 2 nd or 3 rd decade.

In women it is particularly likely to develop at times of hormonal change including those dictated by life-style choices. These will include initiation or stopping of the contraceptive pill, the period immediately after the birth of a baby (post-partum) or in the periods of time before and soon after the menopause. In most women with androgenetic hair loss there is no abnormal androgen production.

Many women who present with androgenetic hair loss in middle age can have experienced an exacerbation of their condition due to medical factors such as iron deficiency anaemia or a low activity of the thyroid gland (hypothyroidism)

Characteristics of alopecia in males and females

There are many similarities of the characteristics of androgenetic alopecia found in males and females. In both sexes there are no factors that can be used to determine whether an individual will develop severe alopecia or not.

Recession of the hair in temporal regions is also common in females occurring in more than 90% of females. It is however less severe and therefore less noticeable in females than in males.

One major difference between the sexes is that females rarely suffer from total baldness and the end result is usually decreased hair density in the affected areas.

 

Medical conditions that can lead to alopecia

Alopecia is classified according to its origin and is generally classified into two groups; destructive or scarring alopecia and dysfunctional or non-scaring alopecia. Medical conditions and environmental factors cause alopecia that fall into these 2 groups and it is the dysfunctional or non-scarring alopecia that makes up the bulk of cases seen today in Caucasian populations.

Destructive or scarring alopecia

These types of alopecia are relatively uncommon and are defined as alopecia associated with destruction of the hair follicles and therefore they tend to cause permanent hair loss. Autoimmune conditions, where the anti-bodies and cells that make up the immune system, attack and damage other parts of the body (e.g. systemic lupus erythematosis or SLE is a disease that attacks the soft tissue in the body).

Autoimmune conditions therefore tend to cause a destructive form of alopecia but more commonly it induces a telogen effluvium . Other conditions such as discoid lupus erythematosis, psoriasis and lichen planus can cause widespread destructive lesions and require treatment by a physician.

Dysfunctional or non-scarring alopecia

There are many conditions that can lead to alopecia but thankfully these are very rare. By far the commonest types of alopecia seen by physicians and trichologists in the UK are androgenetic alopecia, alopecia areata and diffuse alopecia. We will therefore review these conditions first and then we will review the medical diagnoses that should be considered.

Alopecia areata

Alopecia areata can cause a sudden and patchy hair loss in individuals. The condition is relatively common with up to 1 person in 1000 can expect to suffer from the condition at some time during their life. The condition is often localised but severe and widespread lesions do occur.

Discrete patches of hair loss are seen but there is no loss of hair follicles. Alopecia Areata is associated with an increase in antibodies directed against organs in the body and this has led some to suggest that it has an autoimmune mechanism but there is little proof of this concept. It is perhaps surprising that in view of the proposed immunological basis to the condition it occurs with equal prevalence in males and females.

Alopecia areata occurs with types of thyroid disease (hashimoto's thyroiditis), pernicious anaemia, rheumatoid arthritis, vitiligo and diabetes mellitus. There is a family history of the condition in more than 10% of cases.

Alopecia areata is characterised by an infiltration of white blood cells called "lymphocytes" to surround the hair follicles in the scalp. Lymphocytes are the cells in the body that eliminate foreign bodies such as bacteria and are responsible for cleaning dead tissues as they occur. In some diseases their activity is directed against perfectly healthy tissue by mistake, and thus causes a specific type of disease.

In alopecia areata, this process causes damage to the hair follicles, which then causes a progressive weakening of the hair shaft resulting in fractures and shortening of the hair shaft. When these hairs are shed they are relatively short, often being less than 4 mm in length and have a shape that resembles an exclamation mark (!). They can usually be seen with a simple hand held magnifying lens, a microscope is usually unnecessary.

The diagnosis can be made on the characteristic clinical appearance of discs of alopecia associated with hair shaft fracture and the appearance of hairs of the shape of an exclamation mark. Further metabolic investigations are unwarranted.

The hair in patients with alopecia areata can often re-grow but it may take more than one year and when it does re-grow it often lacks pigment. Thus a number of white hairs appear and it can often result in an individual complaining of "going white overnight".

Alopecia areata can be very severe and involve the whole body. This is called alopecia universalis or totalis and is characterised by the loss of body hair, eyelashes and eyebrows.

Therapy for this condition remains difficult and individuals should be encouraged to try several types of product before giving up or being convinced that treatment will not work. Historically injections of corticosteroids into the scalp have been used but often these are associated with significant discomfort. Other treatments involve the application of irritants such as dithranol, or the use of intense ultraviolet light has been recommended (PUVA). Their effect is very variable and some reports suggest little activity in promoting hair re-growth in this condition.

More modern shampoos and cosmetic products such as Thymuskin® have been developed and they have shown encouraging results in this condition and are reviewed in following chapters.

Diffuse alopecia

Diffuse Alopecia is the second most common type of alopecia, coming after androgenetic alopecia which is the most common. Usually it occurs in females and frequently there is a triggering factor. It is thought to be different from the male pattern baldness but in many cases it may simply represent a more rapid ageing of the hair follicles when it occurs in middle age. In a minority of cases a fungal infection of the scalp may be present and this will require appropriate therapy with antifungal agents such as ketaconazole. These are usually available through pharmacies or by prescription.

How Can Thymuskin Help?

Thymuskin has been clinically proven to help women with androgenetic alopecia showing nearly a 100% success rate over 6-9 months. It is often the case that the standard Shampoo and Hair Treatment will resolve most cases of male pattern baldness.

However, to get a better understanding of your personal situation you may like to fill out our online questionnaire so we can review your answers and get back to you with a personalised Thymuskin hair loss regimen. Click here to visit the questionnaire page.

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