Why do some men go bald ? Is male pattern baldness treatable?

Male pattern baldness describes the common loss of hair on the scalp in men. Known as androgenetic alopecia, male-pattern baldness is a result of changing hormone levels over the course of a man's life.

There is a hereditary component to this type of baldness, and men who become bald typically do so in their later years.

Although painless, for many men, hair loss on the scalp can be psychologically distressing. As there are also other causes of hair loss, including some serious health conditions, it is important to establish any underlying factors for baldness.

What causes male pattern baldness ?
Three main factors lead to men becoming bald:
-Genetics
-Age
-Androgens (predominantly male hormones).

These three factors interact and contribute to the risk of gradual shrinkage of scalp  follicles (tiny cavities in the skin at the base of hairs), and progressively shorter and finer hair. Eventually, no new hair grows from the follicles. Androgenetic alopecia also occurs in women, resulting in female pattern baldness.

Almost every white man develops some degree of baldness, with the likelihood of baldness determined by both increasing age and specific genetic factors. Men with more first- and second-degree relatives who are bald have an increased risk of becoming bald themselves.
Androgens are also always involved - castrated men, who do not produce male hormones, do not become bald.
It is estimated that up to half of all white men will have male pattern baldness by the age of 50, while up to 30% of men over 30 years of age develop the condition.
Men who begin to lose scalp hair and who consult a physician may undergo testing for other conditions that can lead to baldness.

Differential diagnoses for male pattern baldness include:
-Telogen effluvium, a disturbance of the hair growth cycle that leads to hair loss
-Endocrine causes - hormone disorders, including hypopituitarism, hypothyroidism ,
 hyperthyroidism , hypoparathyroidism
-Some drugs, including retinoids and anticoagulants
-Excess vitamin A
-Iron deficiency
-Severe chronic illness

Recent developments on causes of male pattern baldness

-Genes associated with early-onset baldness
Comparing the genetic profiles of bald and non-bald men, researchers publishing in PLoS Genetics in June 2012 found six genes associated with early-onset male pattern baldness.

-Protein implicated in male pattern baldness
Scientists from the University of Pennsylvania discovered, in March 2012 work, an abnormal quantity of a protein called prostaglandin D2 in the scalps of bald men, saying there could be a causal link.

Are there any treatments for male baldness ?
For many men, going bald is seen as a natural part of growing older and may not be something that requires treatment. It is not life-threatening - and is not normally associated with any noticeable physical symptoms beyond the hair loss itself.

One recent analysis found, however, that people with androgenetic alopecia may have a slight increase in the risk of cardiovascular disease due to increased levels of inflammation (as determined by elevated C-reactive protein) and lipoprotein.
It is estimated that up to half of all white men will have male pattern baldness by the age of 50 years.
For many men, however, baldness comes with negative psychological effects, including:
-Low self-esteem
-Depression
-General dissatisfaction with body appearance.

The US Food and Drug Administration has approved two drug treatments for male pattern baldness:
-Minoxidil (US brand name Rogaine) - a topical treatment applied to the scalp, available over the counter at pharmacies
-Finasteride (Propecia) - an oral treatment available only on prescription.

In rare cases, finasteride can cause sexual dysfunction, sometimes reducing sex drive or causing impotence and ejaculation disorders; such side effects  subside with continued use of the drug and are reversible by stopping the drug treatment

Finasteride works by blocking dihydrotestosterone, a male hormone implicated in hair loss as it shrinks scalp hair follicles. The drug blocks the formation of this hormone in the scalp, slowing down the progression of baldness related to dihydrotestosterone.
Finasteride can take more than six months

to show some effect on hair growth, and the 1mg tablet usually has to be taken once a day for at least three months. The pill must be continued to maintain its effect, which is otherwise slowly reversed after treatment is stopped.

There is a limited amount of evidence to suggest that combining the two standard treatments increases their effect; finasteride and minoxidil treatment may also be overlapped while switching from one medication to the other.

Two other treatments are available for male pattern baldness, both without prescription, in the form of shampoo. The evidence supporting the effectiveness of the treatments below is poorer than for finasteride and minoxidil:

-Ketoconazole 2% (Nizoral)
-Pyrithione zinc 1% (Head and Shoulders).

Surgical hair transplantation
Hairs in the rear-bottom part of the scalp are more resistant to androgens and so are used in surgical transplants. The hair donated to balding areas remains resistant to the male hormones.
Surgery either involves the excision of a strip of skin, complete with hair, to graft it onto the bald area, or involves the transplantation of individual hairs, which avoids scarring.
Robots have been developed to carry out the procedures, which are expensive - typically costing between $5,000 and $20,000 a session, with one or two sessions needed.

Recent developments in the treatment of male pattern baldness

-Human hair cells grown in the lab
A study published in October 2013 succeeded in transplanting donor hair cells grown in the lab.

-Stem cell clues to reversing baldness
Yale researchers in September 2011 found hair-growth trigger signals in the stem cells of mice.

-Plucking hairs could help treat baldness, study finds
In a new study, researchers may have uncovered a promising - yet surprising - treatment for hair loss: plucking the remaining hairs. Their findings are reported in the journal Cell.

-Drug promises robust new hair growth
A new method of restoring hair growth - using drugs that are already approved for safety - may be on the way, according to research published in Science Advances.

Laser treatment
Laser therapies are yet to demonstrate any evidence of benefit for male pattern baldness and are not backed by the FDA for efficacy. However, such treatment continues to be marketed to balding men at a cost of thousands of dollars over a long course of six to twelve months.

In spite of a lack of evidence for benefit, laser therapy has become more popular in recent years. Manufacturers vary their approaches, offering different lasers and light sources of varying wavelengths, and machines are offered for home or clinic use on a daily, weekly or monthly basis. This lack of consistency may be indicative of a lack of consensus over efficacy.

One research paper on the topic cites "aggressive marketing" and describes clinics "claiming great success in the treatment of hair loss" despite "little scientific data supporting laser/light sources in hair .

Reviewed by Dr Helen Webberley

Written by Markus MacGill