Hair is falling out, it is slow to grow, it is alopecia. The causes vary from patient to patient. Alopecia is a symptom of a disease, a disorder. For doctors, there are two categories of alopecia, scarring alopecia and non-scarring alopecia. Under this classification, the diagnosis can end up being telogen effluvium, the most common form of alopecia, due to a variety of causes. Another condition, the most famous of which is male pattern baldness, but also female pattern baldness, is called androgenetic alopecia (AAG), and it is certainly the most feared of all.
But in any case, the big question is whether regrowth is possible.
How does hair grow naturally?
Healthy hair contains an average of 150,000 hairs. The implanted part is called the dermis Hair follicles. at its base it is hair bulb, the site of rapid cell divisions. Over the course of its life, each hair follicle will produce up to 15 hairs.
the hair life cycle runs straight through Three stages :
- the Anagenor growth, which allows hair to grow several millimeters each week over a period of 2 to 7 years, depending on the individual, gender or ethnic origin.
- a regression phaseor inversion phase, of the hair bulb that lasts 3 weeks.
- a telogen phasethe bulb goes into a resting state, after 5 to 12 weeks the hair that has separated from the bulb is then removed.
80 to 90% of the hairs in the anagen phase make up healthy hair, 10 to 20% are in the telogen phase, and finally, a tiny percentage (1 to 2%) have growth stunted, or are in the telogen phase, before the cycle begins again towards the anagen phase. new growth.
What is alopecia?
Every day, we naturally lose 80 to 100 hairs. After 150 hairs a day, it may seem unnatural. This is called alopecia, either diffuse or patchy fall, sudden or over time. It can be untreatable, and then we talk about itcicatricial alopecia, There will be no regrowth of hair because there is irreversible destruction of the follicle. On the contrary, a Non-scarring alopecia decreases, hair follicle growth slows down but hair loss phenomenon will be temporary, growth is still possible.
The attending physician and then the dermatologist question the patient at length and examine his hair to come up with a diagnosis. Because alopecia takes many forms and can have different causes.
The most famous of them is hereditary hair loss
Baldness is a common word, but it is often referred toHereditary baldness where androgenic (AGG). It affects men more than women. The incidence of symptoms also varies by race: men of European descent are more likely to experience baldness than men of Asian, Native American, or African descent. Finally, with age, androgenetic alopecia is becoming more and more common among males, reaching nearly 80% of those over 70 years of age. In women, it affects one in five women by the age of 40, and one in four women by the age of 60.
According to men, there is a frontal line of hair rising, thinning of the temporal lobes or bays. In others, it is the upper part of the skull, called the head, that first bears the increasingly monk’s tone. Before alopecia, hair has lost its thickness and length, long enough to allow it to penetrate the surface of the scalp. It has lost pigmentation and density, and after molting, only a soft villi remain, the villi, which, in turn, disappear. Dermatologists talk about it Reducing hair follicles Which, from one cycle to the next, becomes vellus in those areas affected by androgenetic alopecia.
Scales for measuring alopecia
For men, the Norwood-Hamilton scale. It was developed by Dr. B. Hamilton in the 1950s, then modernized by dermatologist and surgeon specializing in micro-hair transplants, A.T. Norwood. Norwood and Hamilton established 7 stages of progression of androgenetic alopecia, stages during which hair density is measured in 3 regions of the skull: the temporal, frontal, and cranial (upper part of the skull) lobes.
Hamilton, a physician and anatomist by training, made the connection between the sex hormone, testosterone, and AAG https://onlinelibrary.wiley.com/doi/full/10.1111/exd.12702. His observations in the 1940s focused on residents of an institution for the mentally handicapped in Kansas, USA. The use of castration to exercise control over these patients was common until the 1950s in many US states.
For women, the Ludwig scale was developed in 1977 by Dr. Eric Ludwig, which classifies female androgenetic alopecia into 3 stages, which are stages lower than the Norwood-Hamilton scale. The hair gradually thins around the parting. In the third stage, the upper part of the skull is completely empty.
Causes of genetic baldness
Androgenic alopecia appears when there is a combination of two factors:
– One genetic factor Passed on by one or both parents – or even grandparents. Note that some of these genes are located on the X chromosome, transmitted only by the mother. Thus baldness can be inherited from the mother.
– One hormonal factor. Hair follicles are sensitive to androgen hormones that regulate their growth. It is these hormones that occur in puberty Which affects our hair system: it modifies its thickness, growth rate and distribution to stereotyped areas. Among these androgens, dihydrotestosterone (DHT), a derivative of testosterone, affects the hair growth cycle and precipitates hair. One of the drugs used to delay AGA, finasteride, attempts to reduce the amount of DHT, by blocking the enzyme responsible for its production, 5-alpha-reductase.
Cicatricial alopecia is less frequent
In the case of cicatricial alopecia, the bare skin of the scalp either shows the appearance of red spots, or the appearance of smooth, shiny skin. Falling can be done by specific areas or even touching the entire hair. Hair follicles are destroyed. It is no longer possible to regrow.
This cicatricial alopecia is rare and symptomatic Autoimmune diseases or skin infections Such as lichen planus, lupus, decalvans folliculitis.
What is less known is that certain hairstyling gestures that are practiced daily can cause scarring called alopecia. Traction alopecia. It is therefore necessary to beware of knots or ponytails that are too tight, smoothed and brushed and that cause trauma to the hairline.
Telogen effluvium, transient and reversible alopecia
This widespread, sudden, and abundant hair loss, but often less than 50% of the hair, is considered temporary. Re-growth is possible. It is a non-scarring alopecia. It can fluctuate in cycles over several years. L’Telogen effluvium Alopecia areata is more frequent than androgenetic alopecia. It even makes up a good percentage of consultations with a dermatologist for telogen effluvium. Why “telogen”? Because this hair loss occurs during the namesake phase of the hair cycle.
Its causes are very variable. This recurrent alopecia can occur as a result of pregnancy, taking certain medications, a diet that leads to vitamin deficiencies, and psychological or physical stress (general anesthesia for example). Telogen effluvium can also be seasonal when the spring and fall cycles of many of our hairs coincide. The phenomenon of hair loss can last three months, and it does not affect the total volume of hair. In the case of a longer duration, exceeding 6 months, and a scattered capillary mass, a consultation will be necessary.
Whatever the type of alopecia, it is with the doctor and during the anamnesis, in other words, in-depth questioning and before any physical and biological examination, that solutions will emerge. Pharmacological treatments, vitamin replacements, maybe microsurgery, or maybe giving from time to time.