When hair falls out in abnormally high amounts, various factors can be involved. While androgenetic alopecia is the most common form of hair loss, other forms exist, temporary or long-lasting, extensive or localized. In any case, a rapid diagnosis is necessary in order to set up an appropriate treatment that will promote hair regrowth.

Hair loss can have many causes and manifest itself in a variety of ways. In men, it is most often linked to the genetic make-up and the effects of male hormones that accelerate the life cycle of hair. After a set number of cycles, the hair stops growing. In women, hair loss has many causes, hormonal and otherwise. For example, stress, thyroid problems, diabetes, etc. Some medications can also cause hair loss.

How does hair grow?

On average, a head of hair contains between 100,150 and 000,50 hairs and as many hair follicles (each follicle produces only one hair). Every day, we lose between 100 and <> hairs, which immediately start to grow back.

Our hair grows in cycles. For an average of two to five years in men, three to seven years in women, the follicle produces hair at a rate of about 2 millimeters per week (more in summer). This phase of growth is called the "anagen phase". It is gradually completed in one to two weeks ("catagen phase"). Then, the "dead" hair remains attached to the skull for about three months before falling out. This is the "telogen phase". As soon as the follicle falls, it resumes a growth phase.

The course of this cycle of growth - telogen phase - fall is under the influence of diet, hormones (thyroid and sex), heredity, certain growth factors, chemical mediators of the nervous system, etc.

Each hair follicle is capable of performing between 20 and 25 cycles before it becomes exhausted. At an average rate of five years per cycle, between 100 and 125 years of hair are insured! But sometimes this process stalls and abnormally large hair loss occurs. Usually, pathological hair loss is considered when the number of hairs lost each day is greater than 100, or when one area of the scalp loses more hair than the rest of the skull.

Various methods exist to diagnose abnormal hair loss, for example taking successive photos of a fixed region of the scalp, to count hair in the telogen phase (phototrichogram). In addition, a microscopic examination of the hair (trichogram) can give information about the causes of this loss.

What are the symptoms of hair loss?

Hair loss can be localized or diffuse, temporary or long-lasting. Classic male pattern baldness is a long-lasting, localized form on the top of the head. Hair loss after childbirth, general anesthesia or psychological shock, called telogen effluvium, is a temporary diffuse form, with complete regrowth in 3 to 4 months. Some localized hair loss can be infectious, such as ringworm, or autoimmune, such as alopecia areata.

What are the treatments for hair loss?

Treatments for hair loss depend on the cause. Ringworm is treated with a fungal medication, alopecia areata with corticosteroids or ultraviolet rays. Diffuse falls such as telogen effluvium grow back spontaneously and do not require treatment, except sometimes iron supplements. Male pattern baldness can be prevented with treatment if caught early enough. Micro-hair transplants taken from the sides are possible and their effect is long-lasting.