Alopecia: all the best to know about hair loss!

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In dermatology, alopecia is the acceleration of hair or body hair loss. This word comes from ancient greek alopekia and alopex, meaning fox. Foxes lose their winter hair in early spring. It is alopecia when the hair loses an excess of 100 hair per day on an extended period. Baldness is the ultimate development of alopecia.


Baldness has been a significant cause of worry for men through the times. An allegoric Talmudic story (Kora’h parashah) tells the conversation of a bald wise man and a hairy eunuch. 

Since the Antiquity, men have used various techniques to hide baldness. In the Antiquity, men use empiric and natural treatments. They put horse saliva, goose poop, or spider webs on their scalps, thinking it would make the hair grow back.

Many scammers sold “miracle remedies” to baldness in the XIX century.


Normal and abnormal hair loss

On average, we have 100 000 to 150 000 hair, and we lose 40 to 100 of them per day. A typical loss may go up to 175 per day during the season change, mainly in spring and fall. Hair renews the most during this phase. Alopecia occurs when there is a loss of more than 100 hair per day during an extended period, up to two months. 

A doctor needs to diagnose this loss’s cause, and he may need to do a “Trichogramma.” He takes some hair in different head areas and observes them under a microscope. Baldness is when the loss is on the forehead, temples, and top of the head. In women, doctors often need a hormonal checkup to find the causes of hair loss.


There are five types of alopecia:

  • Genetic androgenic alopecia is the most common. It involves hair volume decrease or baldness. It affects 70% of men (20% of men between 20 and 30, on them, hair loss starts at 20 and stabilize at 30).
  • Acute alopecia may be due to chemotherapy, stress, vitamin and mineral deficiency, iron deficiency, hormonal disorders, or irradiation.
  • Localized alopecia may be triggered by skin problems (tumor, burns, autoimmune alopecia), radiotherapy, or parasites (tinea capitis, lichen).
  • Congenital alopecia
  • Areata alopecia would be autoimmune. It involves bald patches of various sizes on one of several body parts. This autoimmune alopecia form may affect the whole head: totalis alopecia. In other cases, it affects the entire body; it is Universalis alopecia, leading to the loss of all hair and body hair.


Hair cycle phases

Anagen phase

The anagen phase is the growing phase of the hair. It is the most extended period of the hair cycle, lasting 2 to 5 years. Most of our hair is in the anagen phase.

Catagen phase

The catagen phase is a rest phase. During it, the hair keeps evolving. It lasts about three weeks, which is very short compared to the previous stage.

Telogen phase

Hair does not grow during the telogen phase; hair does not grow but remains attached to the follicle. At the end of the stage, the old hair falls and gives its place to a new one. The cycle starts over.


Hormonal causes

Androgenic alopecia

Androgenic alopecia is a gradual hair loss due to male hormones. It usually appears between 30 and 40 years old. It affects 70% of men worldwide. In some cases, androgenic alopecia may occur in men as young as 16. Hair loss causes are numerous; dihydrotestosterone (DHT) is mainly responsible. However, the scientific community agrees that it would not be the only hormone responsible for hair loss. Epitestorone would also play a crucial role in the process.

This hair loss usually starts on the temples and the top of the head. Hair becomes thinner and falls. The loss may be slow or sudden, depending on people. The Hamilton scale, later modified by Norwood, helps to grade baldness from 1 to 7. 1 is no baldness, while 7 is the maximal alopecia (total loss on temples and vertex).

Norwood’s scale is not suitable for all androgenic alopecia cases. Some men suffer from alopecia that usually affects women: affecting the hair part. Ludwig’s scale measures this type of androgenic alopecia.

In 2011, a study showed androgenic alopecia is not due to the diminution but the inactivation of hair follicles stem cells. Those cells do not turn into hair “progenitor cells,” leading to atrophy follicles. The follicles produce microscopic hair. A bald man has as much hair as a non-bald one, but they are invisible because they are tiny.

The crown hair does not fall because it does not react to testosterone.

Postmenopause alopecia

It is the most common baldness type in women. It occurs after menopause when the protector roles of the feminine hormones disappear. The hair is more fragile, its lifespan shortens, and definitive alopecia may appear. 

In women, hair loss is more diffuse and extensive than in men. Women do not have bald spots; they suffer from diffuse hair loss. This process rarely leads to total alopecia. Hair on the side of the head does not fall. Typically, the median part progressively enlarges. This phenomenon is graded on the Ludwig scale.

Before menopause, an iron deficiency, such as during a heavy period, would be responsible for hair loss. Chronic stress would also lead to alopecia. Some skin diseases trigger alopecia.

Nutritional causes

Besides hormonal causes, hair loss may be due to iron, copper, zinc, silicon carbide, and vitamin B deficiency. This hair loss affects about 20% of people following a moderate to a strict diet. However, it is more often linked to bulimia or anorexia. Most of the time, people get their back after a while; it may take up to 2 years.

Toxic causes

Some medicines, such as chemotherapy) and poising causes a sudden hair loss. Even with a shallow dose, as with polonium 210 acute poisoning.

This type of alopecia is a part of acute irradiation syndrome.

Autoimmune alopecia

Autoimmune alopecia causes hair or body hair loss in delimited areas. It is an autoimmune skin appendages disease. The triggering cause of this disease remains unknown.

There are three main autoimmune alopecia types:

  • Areata alopecia (localized spots)
  • Totalis alopecia (head only)
  • Universalis alopecia (entire body)

Both genders have 2% of the risk to develop an Areata alopecia in a lifetime. Half of the cases occur in patients under 20. Less than one case out of ten evolves to a severe form.

Half of the case evolves to improving and healing in one month, but the relapse is frequent. The mild forms do not need treatment, except for a cosmetic one. There is no consensus on treatment.


Drug treatments


This medicine was first named Proscar and was sold to treat benign prostatic hypertrophia. Then, doctors figured out Finasterid blocked type 2 DHT and helped the hair grow back. According to clinical trials, 82% of the subjects noticed a stabilization of the baldness and 60% a more or less significant growth. Pregnant women should never touch Propecia pills as this medicine is proved to cause deformities in male fetuses.

Long term side effects of Propecia are still poorly known:

  • In most cases, they are temporary and disappear after the end of the treatment. However, in some cases, patients reported persistent side effects.
  • Permanent sexual dysfunctions were documented. Finasteride intake most often causes low libido, erection problems, a decrease of ejaculate volume, mammary and testicular abnormal sensitivity, allergic reactions (cutaneous eruptions, urticaria, rash, gynecomastia, and fatigue. 

Propeciahelp website gathers more than 1 400 people complaining about persistent side effects of Finasteride. Dr. Irwing conducted a study with members of this website and showed that low libido affected 94% of men, erection problems (no morning erection) concerned 92% of them, and 69% had trouble reaching orgasm. On average, those men used Finasteride for 28 months but experienced sexual side effects 40 months after the treatment. However, those figures only involve people who testified on this website.

  • This medicine can damage the internal organs of pregnant women and their children.
  • Recent studies showed Propecia might lead to depression and suicide.

Women and children should not take Finasteride.

Patients may apply it cutaneously.



Minoxidil was the first treatment sold to cure baldness under the name of Rogain. Many generic versions of this molecule are available (Alostil, Kirkland, etc). Its action is unknown, but many researchers believe it dilates the veins and increases blood circulation in the scalp, bringing more nutrients to the hair follicles. Patients must apply this product twice a day and lose the hair that grows with it if they stop using it. It exists two versions: 2% and 5%.

Women can only use the 2% version, while men can use both. The 5% version is more efficient.


First, pharmacologists did not create this medicine to treat baldness but to cure benign prostatic hypertrophy. This medicine would be 1.5 more potent than Propecia to reduce DHT (figures to confirm). This medicine has a lot of side effects, very similar to Propecia. Dutasteride would have twice as many side effects as Propecia.

Cosmetic medicine


This technique involves harvesting grafts on the crown (eternal hair) to graft them on the top of the head. This technique is the only definitive solution to hair loss because grafted hair never falls. This technique may not be efficient to graft the entire head because there are not enough hair follicles on the crown to cover the whole head. This technique’s results mainly depend on the surgeon’s skills. If the grafts are implanted in the wrong sense, the patient’s hair will be impossible to style. It exists a hair transplant technique using a robot to harvest the grafts.

LLLT: Low-Level Laser Therapy

LLLT, Low-Level Laser Therapy is biostimulation. Tests on mice proved it help hair to grow. In the USA, considering the price of the diodes, people make their laser helmets. This therapy involves three 20-minutes sessions per week. Minoxidil may boost the results.


Powder and spray

Powders and spray may help to hide baldness. The core principle of this method is to densify hair. Those products may be colored to hide roots on colored hair.


Wigs are an excellent tool to hide baldness and excessive hair loss, such as the one chemotherapy or autoimmune alopecia cause. Exists both synthetic hair and natural hair wigs.

Hair prosthesis helps to hide localized baldness. It is suitable for women who suffer from diffuse baldness and lack hair volume. It is a net with hair. This net is fixed with various techniques (braiding, glue, clips) on the patient’s remaining hair.

Hair complements are implanted into lace or injected in copolymer polyurethane, sometimes called micro or nano skin. The prosthesis may be glued fixed using adhesive strips, clips, braids, or sewing. In men, many stars use those systems. John Travolta has been using them for over two decades.

Hair tattoo

Micro Hair Tattoo (MHT) injects a small amount of pigment inside the scalp with a surgical dermograph to imitate shaved hair.