Androgenetic alopecia (male pattern hair loss, commonly baldness) is the most common form of alopecia in men and one of the most common in women. It is estimated that 70% of men and 40% of women will experience it at some point in their lives, and one in two men will suffer from it at the age of 50. Androgenetic alopecia is due to the effect of androgens on the hair follicles, while there is also a genetic predisposition for its appearance. Both genetic and environmental factors play a role in its emergence and development, while the full causes still remain unknown.
The responsible genes are being investigated; the majority of these are located on the X chromosome and are recessive. This is why women more rarely suffer from androgenetic alopecia, as it requires the existence of pathological genes on both X chromosomes to manifest itself. In men, a single gene on the only X chromosome available suffices to exhibit the disorder. Recent research has shown that the hereditary substrate of androgenetic alopecia is even more complex; genes have been found that control, among others, the time of onset of androgenetic alopecia, the speed of its development and the manner of manifestation.
The clinical picture of androgenetic alopecia varies in men and women. Classical androgenetic alopecia in men is characterised by loss of hair on the temples, thinning of hair on the crown of the head, and a gradual recession of the hairline. Even in advanced stages, a strip of normal density remains in the lateral temporal regions and on the rear (occipital) part of the scalp, and complete hair loss rarely appears. Androgens are important growth hormones of the male sex. They control the function of the sebaceous glands, stimulate the growth of body and facial hair, and suppress the growth of hair in the frontotemporal region, leading to androgenetic alopecia.
In men who suffer from androgenetic alopecia, the enzyme 5-alpha-reductase is increased. They also display elevated levels of free testosterone and dihydrotestosterone and reduced levels of total androgens. In the hair follicle, 5-alpha-reductase converts free testosterone into dihydrotestosterone (DHT), which plays a dominant role. Other factors that contribute to the development of androgenetic alopecia are mental illness, heart disease and prostate cancer.
Female androgenetic alopecia usually occurs as diffuse thinning of the hair, without recession of the hairline. In most cases, hair thinning is more intense at the top of the scalp. Unlike in men, total loss of hair in the affected area is rarely observed. Apart from heredity, there are also other factors that lead to female androgenetic alopecia, such as the reduction of female hormones during menopause, polycystic ovary syndrome, congenital adrenal hyperplasia, virilising adrenal and ovarian tumours, Cushing‛s syndrome and chronic use of cortisone.
A recent study in identical female twins revealed several factors that can be associated with an increased incidence of androgenetic alopecia in women. Such factors are diabetes mellitus, hypertension, lack of exercise, long hours of sleep and an unstable marital relationship. Also, not wearing a hat and exposure to UV radiation contribute to the onset androgenetic alopecia in women. Finally, anxiety and stress accelerate the condition in both men and women.
The psychological impact of androgenetic alopecia is enormous in both men and women. Rich and strong hair has always been regarded as an important element of beauty. Patients who suffer from hair loss have low self confidence, are less sociable and often have difficulties in their interaction with the opposite sex. This explains why people with androgenetic alopecia have always been seeking solutions to their problem.
The diagnosis is, basically, clinical. The trichogram is one of the oldest techniques for the diagnosis of androgenetic alopecia and shows a very large increase in telogen and dystrophic hairs, compared to anagen hairs. A full haematological and hormonal check is advisable, in order to exclude underlying disease, especially in female androgenetic alopecia. Trichoscopy is a new method, diagnostically equivalent to dermoscopy. The process uses a digital microcamera that shows the affected area and takes a photo-trichogram. In case of doubt, a scalp skin biopsy may be required in order to differentiate androgenetic alopecia from alopecia areata or cicatricial alopecia.
Androgenetic alopecia – Classification
Androgenetic alopecia – Treatment
Treatment of androgenetic alopecia is a matter of great interest to the patients, as it is a serious aesthetic issue with significant psychological consequences. The need to find an effective treatment is reflected by the multitude of substances (from topical creams and lotions to vitamins pills and shampoos) that have been used in the past and continue to be used, promising successful treatment.
Treatment of androgenetic alopecia can be divided into non-hormonal therapy, hormonal therapy and surgical therapy.
The only non-hormonal treatment with proven results, is minoxidil (in 2% or 5% solution) in the form of lotion or foam. Hair loss in its early stages may be slowed down or even reversed with topical use of 1 ml minoxidil twice a day. The drug is essentially a biological modifier which acts by increasing blood circulation to the scalp and should be applied for several months. Recent investigations have shown that minoxidil interferes in the mechanism of alopecia by prolonging the anagen phase of the hair, thereby increasing its lifetime. The maximum effect of this treatment for androgenetic alopecia is achieved after at least six months of continuous use; upon discontinuation of the drug, the beneficial effects of the treatment are lost. It has been shown that stopping the use for 15 consecutive days leads to regression of the results and to resumption of hair loss. The side effects of minoxidil are not serious and include dryness, irritation, flaking scalp, facial hirsutism and, in rare cases, allergic dermatitis. These side effects limit its use as a treatment for hair loss in some patients.
Hormonal therapy of androgenetic alopecia in women includes contraceptives, if the cause of alopecia lies in diseases such as polycystic ovaries. Postmenopausal women may be treated with hormone replacement therapy with oestrogen and progesterone. Spironolactone is also used in the treatment of androgenetic alopecia in women; it reduces the production of androgens and the activity of 5-alpha reductase.
Principal representative of hormonal treatment of androgenetic alopecia in men is finasteride. Finasteride is antiandrogenic, an inhibitor of 5-alpha-reductase, and is administered orally at a dose of 1 mg per day. It is considered to be a very effective treatment, as it stops hair loss in 90% of men and leads to hair regrowth in 65% of the cases, according to studies. It is most effective in young patients, up to 30 years, for alopecia from the incipient to the middle stages (I-IV on the Norwood-Hamilton scale), but becomes less effective at higher ages due to the lower levels of androgens in the blood. When administered as treatment, finasteride reduces the levels of PSA in the blood and can thereby mask a possible carcinoma of the prostate; therefore, it is advisable to avoid its use in patients who are more than 50 years old. As a treatment for women, it can be used after menopause. Side effects of finasteride are the reduction of libido and gynaecomastia.
Surgical treatment of androgenetic alopecia involves hair transplantation, which is also the only definitive treatment. The preferred method is FUE, which is painless, does not leave any scars or marks, does not require stitching, and gives a perfectly natural result. FUE hair transplantation is indicated for both men and women suffering from androgenetic alopecia, regardless of the patient’s age or degree of progression. One other method that is still used to a significant degree, is the older hair transplant technique FUT, otherwise known as strip technique. Over recent years the use of FUT has become less popular, as more and more patients prefer the less traumatic FUE technique.
Other modern treatments include low level laser treatment (LLLT) and treatment with PRP (Platelet Rich Plasma), which involves injection of plasma from the patient’s blood into the affected region. After appropriate activation, the plasma is injected into the scalp and by producing growth factors, leads to the development of new cells, improves blood supply to the scalp area and strengthens the affected hair follicles. As it takes advantage of the body’s own healing forces, it is one of the most effective modern treatments for androgenetic alopecia.