Manufacturer and worldwide distribution of Aesthetic, medical and surgical devices
Automation in Hair Transplant – Anti aging treatments – Slimming treatments
In dermatology, alopecia signifies the acceleration of hair loss. (The term comes from the Greek alopex, meaning fox, because of this animal's annual loss of fur). If alopecia is not slowed down, it ends in partial baldness, or even a total lack of hair.
Among all the forms of alopecia recorded in medicine, the one known as androgenic (or androgenetic) alopecia is undoubtedly the most widespread (90% of the cases of alopecia). It may start early: at 20 years of age one man in five loses his hair, at 30, one man in three and at 50, one man in two.
Although androgenic alopecia mostly affects men, it affects 10% to 15% of women suffering from hair problems.
The role of male hormones in androgenic alopecia
It is called androgenic, because it is linked to two main factors:
* genetic predisposition: a gene that has not yet been isolated is responsible, evidenced by the fact that you have a greater risk of hair loss if you have bald parents or grandparents
* male hormones or androgens
There are two types of male hormones in men as well as in women: testosterone and DiHydroTestosterone (DHT). The testosterone circulating in the blood is changed into DiHydroTestosterone under the influence of an enzyme: 5-alpha reductase.
It is not the amount of testosterone secreted which is the causative factor in androgenic alopecia, but rather the more or less "voracious" way it is picked up by the receptors (located on the genetically programmed hair follicles), then changed into DHT under the influence of the hyperactivity of the 5-alpha reductase. The DHT then disrupts and degrades the role of the follicles: sebaceous secretion increases, and the progression of the developmental cycles of the hair becomes abnormal by speeding up.
In other words, androgenic alopecia is not a hormone disorder but a "receptor disease". As soon as the genes responsible for this disturbance are isolated, this disorder will be able to be eradicated by gene therapy. Several teams of geneticists are currently working on this throughout the world. However, we will undoubtedly have to wait many years before benefiting from it.
A hair is made up of a stem, the loose part which emerges from the surface of the scalp, and a root (bulb) implanted in a hair follicle.
We all have between 70,000 and 150,000 hairs.
The life of the hair progresses in three phases:
Each of the bulbs is genetically programmed to generate 25 cycles during its lifespan, normally ensuring a sufficiently abundant head of hair well beyond the average life expectancy.
On a healthy head of hair, about 85% of the hair is in the growth phase, 2% in the resting phase and more than 10% in the falling out phase. Therefore, it is normal to lose up to 100 hairs a day with peaks of up to 175 during seasonal changes.
Hair loss is considered abnormal when a person loses more than 100 hairs per day during an extended period, which may last as long as 2 months. It is then necessary to consult one's doctor, who will make a precise diagnosis of this loss based on various tests.
In androgenic alopecia, the hyperactivity of the 5-alpha reductase enzyme will, in genetically predisposed subjects, lead to shortening of the growth phase (anagen phase) of the hair and miniaturising this hair in the growth phase.
The duration of each cycle will decrease considerably and go from an average of 5 years to a few months. The 25 hair cycles will be used up much more quickly, leading to a thinning of the hair, then to total progressive disappearance over large areas of the scalp: temples, front and top of the head.
When the lifecycle of a hair follicle is used up, unfortunately there is no more hope of the hair growing back. This is when the solution of the micro-graft becomes necessary.
Fortunately, the hormone receptors of the pilo-sebaceous follicles located on certain parts of the scalp are not sensitive to this hyperactivity of the 5-alpha reductase; this is the case with hair located at the nape of the neck and at the temples, explaining why bald men almost always retain a ring of hair.
It is precisely this favoured area of the scalp in men as well as women (donor area) where the hair benefits for life from a normal progression of its cycle, which will be used in hair transplantation techniques as a hair reserve designated for transplantation in the area that needs to be made thick again (recipient area); in fact, even when this hair is grafted onto the recipient area, it continues to benefit from a normal rhythm of its cycle, whereas the pre-existing hair neighbouring this same area is inexorably destined to permanently fall out.
The progression of androgenic alopecia in men is defined by the Norwood Hamilton classification describing the various stages of baldness by ascending order of exacerbation on a scale of I to IV (see hereafter).
In genetically programmed women, especially during menopause when their level of oestrogens that had been protecting them from DHT goes down, hair loss is more diffuse and extensive than in men. Thus, women do not present bald spots but notice rather an overall thinning of their hair with a gradual expansion of the middle line where the hair is parted. This is what we call diffuse alopecia.
The progression of androgenic alopecia in women is determined by the Ludwig classification describing the various stages of baldness in women by ascending order of exacerbation on a scale of I to III (see hereafter).
