The symbolism of hair is very strong in all peoples and in all times:
– In India, shorn hair is offered as a sign of humility towards their God.
– Catholic monks shaved their heads before entering the orders, to symbolize submission to their God.
– Religious Jews put a kippa on their head as a sign of humility towards God.
– Beyond its spiritual significance, the forced deprivation of hair was a mark of humiliation for the oppressed and of domination for its instigator.
During the last world war, women who had frequented the enemies were shaved.
Hair is perceived as an ostentatious symbol of femininity, so that hair loss is a recurring concern among women.
Generalities about hair
There are between 100,000 and 150,000 hairs on the scalp, i.e. 300 hairs per cm2.
The diameter of a hair varies between 50 and 100 microns.
The structure of the hair is complex.
The keratin proteins which form the macrofibrils are linked together by disulphide bridges which are covalent bonds between the cysteine.
These bridges represent the skeleton of the hair fibre and determine its initial shape. Straightening destroys the disulphide bridges.
The 3 phases of the hair cycle
The anagen phase: this is the growth phase. It lasts about 5 years. It is this phase that is shortened in the case of androgenic alopecia. (85% of hair is in the anagen phase).
The catagen phase: is the resting phase and lasts about 3 weeks and concerns 3% of the hair.
The telogen phase: corresponds to the expulsion of the hair. It lasts 6 months and affects 12% of the hair. The number of hair cycles would be around 25.
During the last growth cycle, the hair follicle will not be replaced by a new hair and it leaves an empty hole on the scalp.
The growth is 0.5 and 1 cm per month.
The hair cycle is subject to variations in age, genetics and diet.
We have 300 hairs per cm2 and about 150 to 60 years old.
This is a normal sign of ageing, such as wrinkles or falling jowls.
The cycles vary according to different factors
1. Exogenous factors :
Dietary factors: vitamins such as vitamin B6 (pyridoxine), vitamin B5 (pantothenic acid), vitamin C and vitamin B8.
The polyunsaturated fatty acids, linoleic and linoleic acid, reduce the harmful action of 5α réductase on the hair cycle.
Seasonal factors: autumn, spring.
The synthesis of melanins by melanocytes. They colour the skin, eyes and hair.
The melanocytes present in the hair follicle are capable of synthesising melanin in the absence of UV light.
They have a protective role: melanins absorb part of the sun’s rays, blocking free radicals.
A certain number of medicines can be responsible for hair loss.
2. Genetic factors :
AAG chronically shortens the duration of the anagen phase of the hair cycle. Hair cycles will be exhausted prematurely.
- AAG has a high prevalence in men.
- It affects approximately:
- 15% of men at the age of 20,
- 30% at 30 and 50% at 50,
- 20% of women at the age of 40.
- 5α-reductase converts testosterone to DHT.
- Genes that are believed to be carried on the X chromosomes.
- They induce a sensitivity of the bulb to DHT and increase hair cycles by decreasing the anagen phase.
3. Hormonal factors:
Estrogens slow down the anagen phase. During pregnancy the hair is beautiful, after childbirth the sudden drop in oestrogen levels leads to hair loss.
In hypothyroidism the hair is rarer, dry and brittle.
Alopecia induced by transient inhibition of the hair cycle
1. Due to deficiency origins such as lack of: iron, vitamin C, vitamin D, vitamins of the B group.
2. Telogenous effluvium represents a sudden loss of hair after a trauma or stress between 1 and 3 months before. (Fever, psychological stress, surgical intervention).
3. Chemotherapies: are responsible for anagen effluvium, between 1 and 3 weeks after the injections.
4. Infections of the hair follicle: can be induced by fungi (microsporum or trichophyton), ringworms, or staphylococcus aureus or propionibacterium acnes, causing bacterial folliculitis.
5. Compulsive disorders: trichotillomania.
6. Diseases: alopecia, lupus, lichen, scleroderma, fibrotic frontal alopecia, in some women after the menopause.
FROM L’ORÉAL RESEARCH AND INNOVATION BY B.BERNARD AND M.VERSCHOORE
Classification by type:
– type I (steep),
– type II (wide corrugation),
– type III (corrugated),
– type IV (curly),
– type V (very curly),
– type VI (coiled),
– type VII (very rolled up),
– type VIII (coiled in a zig zag).
Tensile strength, elasticity
A strand of 100 hairs will withstand a weight of 10 kilograms.
- Between 0 and 2% extension is the « linear elongation region.
- Between 2% and 25-30% extension is the « plastic region ».
- Above 30% extension is the « post-plastic region ».
- When the hair is wet, styling is easier. The load is half that of dry hair.
- Frizzy hair is more fragile under traction because it is more twisted and has flattened areas to the point of strangulation at the elbows and inversions in the direction of a twist.
- Asian hair, having a shape close to a cylinder, is very strong, regardless of its diameter
Permeability and swelling
An anisotropic swelling of the fibre is observed with an increase of 15 to 20% in diameter and 0.5 to 2% in length.
– Frizzy hair naturally has fewer moisturising substances than Caucasian hair.
Classification of hair according to its physical characteristics
– African or frizzy: an elliptical section and a variable diameter can be seen on different parts of the hair shaft. Like a flattened ribbon, it tends to twist around itself and forms frizzy looking hair.
– Asian: the largest diameter is noted. Its morphology is similar to that of a cylinder. The hair is like straight stems.
– Caucasian: we note a diameter and a section of intermediate size. The hair can be straight as well as curly.
Characteristics of African hair
The shape is helical and spiral.
The appearance appears voluminous.
The hair density is weaker than that of Caucasian hair.
The lack of lipids decreases the cohesion of the cubic cells and weakens the structure of the hair.
The sebum does not flow properly because of the helical structure and the numerous tendrils.
African hair contains 99% melanin.
– It has been shown by Khumalo that there are 16.5% knots in African hair, compared to an almost total absence of knots in other ethnic groups.
– The formation of these knots, which are very tight, affects the cuticle which frays and leaves the cortex exposed.
Sebum from the sebaceous glands acts as a lubricant for the scales on the hair shaft.
The frizzy, delipidated hair is therefore less well protected.
African hair grows more slowly than Caucasian hair.
Alopecia by permanent destruction of the hair follicle
In this type of alopecia, the hair follicle being destroyed in an irreversible way, the hair loss observed is definitive.
– Alopecia of genetic origin: AAG. There is aplasia, hypoplasia or dysplasia of the hair follicles, congenital or acquired.
– Alopecia of endogenous origin: due to dermatoses leading to destruction of the follicles (chronic lupus erythematosus, lichen, certain chronic folliculitis, tumours).
– Alopecia of exogenous origin: induced by traumatic factors such as burns, radiodermatitis, repeated tractions, etc.
Cosmetic traumatic alopecia
– Tractions are important on the hair: chignons or braids or hair extensions that are too tight, too frequent brushing. Women with frizzy hair style their hair almost systematically by pulling on it.
– As frizzy hair is naturally more fragile than other types of hair, these women are strongly predisposed to suffer from this traction alopecia. The prevalence would be: 17% of these women from the age of 16 and 31% from the age of 18.
– The Austrian dermatologist Trebisc in 1907 had noted definitive alopecic areas observed on the temples and back of the skull in young women living in the far west region of Greenland.
They used to frequently comb their hair with a ponytail as in Japan and Europe in the early 1930s.
This involved populations of women making hairstyles with the help of buns.
There are definite alopecic areas among African women according to their hairstyling habits and the use of cosmetic products that are too aggressive for their fragile hair.
It is a non-scarring alopecia at the beginning of its evolution. Maintaining traction on the hair shaft will lead to the permanent destruction of the hair follicle and secondarily induce permanent scarring alopecia in the frontal and temporal areas.
Chemical alopecia and the use of hair relaxer products
– As early as 1995, it was estimated that 80% of African-American women had already used a relaxer.
– Today, it is estimated that 2/3 of African women use relaxers to make their hair easier to style and to achieve longer hair.
– These products cause many undesirable effects, including chemical alopecia.
Chemical alopecia and traction alopecia are among the 5 most diagnosed dermatological pathologies among African-American women.
Chemical alopecia at the active, inflammatory stage:
– Folliculitis will be aggravated by the use of comedogenic hair products (oils or ointments applied directly to the scalp) and the use of allergenic synthetic hair extensions.
– The following can be noted:
– Pustules around the roots of the hair stems exposed to strong tension,
– The formation of a perifollicular erythema, with a greyish appearance,
– Hyperkeratosis and pruritus which are reminiscent of seborrheic dermatitis.
– Alopecia is non-scarring: it is still reversible.
– A particularity linked to these women with African origins is a higher prevalence of martial deficiency, when a diagnosis of fragility of the hair shaft is made.
The causes are multiple, sometimes constitutional, for example sickle cell disease, or acquired through the practice of ingesting kaolin. A ferric assessment will then be useful in order to prescribe an iron supplementation if the ferritin is below 40 μg/L.
Caustic chemical alopecia
– It is part of the non-scarring alopecia caused by a chemical trauma, the purpose of which is to relax the skin.
– The frequent use of caustic cosmetic products evolves towards irreversible scarring alopecia.
– Straightening deforms the structure of curly hair to make it smooth. The product destroys the covalent bonds of the keratin protein which are the disulphide bridges.
– Hydroxide-based straighteners: are very corrosive.
– Soda-free no-lye relaxers: have a lower relaxing power but the same corrosive effect.
– Relaxers based on thiols, sulphites or bisulphites are used for curly perms. These relaxers have a low smoothing power, but are very gentle on the hair and scalp.
– The first chemical relaxers put on the market at the beginning of the twentieth century were used exclusively by men.
– Considered very corrosive, their very rudimentary formulas contained soda, lard and boiled eggs.
– African-American women began to use chemical relaxer in 1960.
The mechanism of action of relaxers
– Thiol-based relaxers: breaking of disulphide bonds by a reducing agent and mechanical smoothing.
– Hydroxide-based relaxers: Relaxing is done in a single step by breaking the disulphide bonds and fixing the resulting deformation.
A too long application time favours the development of a chronic inflammation of the hair follicle, which will form the basis for scarring alopecia.
Relaxers will have an effect
on the scalp on the one hand
and the hair shaft on the other
– 1. Effect on the hair shaft: after straightening, the African hair undergoes a structural deformation of its keratin protein. Straightened and broken hair concentrates 3 times less cystine than uncleared hair, when the application time of the relaxer is over.
This causes the hair shaft to crumble or break and the hair to dissolve. The cystine concentrations found in the distal extremity to the hair of relaxed people with or without a breakage, are very much reduced.
– 2. Effect on the scalp. Formulas with a very alkaline Ph of between 13.2-13.3 are responsible for scalp burns.
Centrifugal central scarring alopecia
These traumas are due to chemical (the straightening) and mechanical (the traction) aggressions.
They provoke a chronic inflammation of the cells of the hair follicle with :
– Premature degeneration of the internal epithelial sheath.
– Inflammation leading to the formation of a lymphocyte infiltrate.
– A fibrous tissue aggregates around the hair follicle.
– The inflammation becomes chronic; a granulocyte infiltrate amplifies the inflammatory reaction.
– The stem cells in the region of the bulge are affected by these repeated inflammatory reactions, they cause a degeneration of the hair follicle which will no longer be able to produce hair.
– The loss of the sebaceous gland.
– Only the hair arresting muscle remains. Alopecia begins in the centre of the scalp, which presents a circular, hairless, smooth, sometimes shiny area with no apparent inflammatory zone. Alopecia is chronic and its progression allows the alopecic plaque to expand centrifugally.
1/ The interrogation specifies the occurrence of the pathology:
– The date of the beginning of hair loss to estimate its oldness.
– The circumstances of the occurrence of this fall.
– The evolution over time in order to know if the hair loss is acute or chronic.
– The hairdressing modalities: the hair care habits of the patients.
– The use of medications that cause effluvium.
– The presence of general disorders, chronic illness (asthenia).
– Family history.
The search for locations other than the scalp (in order to eliminate autoimmune diseases such as lupus erythematosus).
2/ Examination: clinical exploration of the scalp and hair:
The examination of alopecic areas is done with a magnifying glass or a dermatoscope.
A dermatoscope or a magnifying glass may be sufficient to make a diagnosis of scarring alopecia.
We look for signs of primary scarring alopecia which are:
– Irregular spaces between the hairs; this is known as « hair tufting ».
– Erythema, desquamation, perifollicular hyperkeratosis.
– Depigmentation and pain in the inflammatory area.
– A history of keloids.
– The presence of dandruff and pain on the scalp.
– The dry or dull appearance will be suggestive of hypotrichosis, a deficiency affection. – Small, short and fine hair, miniaturization of the hair bulb with a two-pore topography and or tonicity in androgenetic alopecia.
– “Exclamation point » hair and circumscribed alopecia are pathognomonic for alopecia.
– A diffuse form in the case of telogen effluvium.
– Border or marginal alopecia in the case of traction alopecia.
– Vertex alopecia in women with frizzy hair, which is reminiscent of central centrifugal scarring alopecia.
3/ The trichogramma
– Can help determine the etiology of certain hair losses.
– For diffuse hair loss.
– In children, it can help diagnose decayed anagen hair syndrome.
– To quantify the importance of the fall and monitor the effectiveness of a treatment.
4/The manual traction test
– On hair that has not been washed for 48 hours.
– Carried out on three distinct areas of the scalp.
– Pinch a strand of about ten hairs between thumb and forefinger.
– It is considered normal when the result allows to collect
o Between 1 to 3 hairs per tested area.
o + 3-4 hairs
o ++ 5-6 hairs
o +++ more than 6 hairs
5/ The biopsy
– Androgenetic alopecia: the location of the alopecic zones located on the vertex.
– Traction alopecia.
– In the case of central centrifugal scarring alopecia, the hair follicles can be seen on histological sections by biopsy of the alopecic area:
– Total loss of the internal epithelial sheath surrounding the cortex.
– The beginning of inflammation.
– The formation of fine fibrous tissue surrounding the cortex.
– Perifollicular desquamation.
– A total cessation of all mechanical and chemical hair practices.
– High dose of topical corticosteroids (500 mg).
– Tetracycline twice a day for 6 months.
Then the doses of medication are gradually decreased until they are totally stopped, when the absence of inflammation lasts a year.
Seborrheic dermatitis treatments can be added to calm the pruritus.
– Alopecic plaque camouflage techniques are used.
– coloring sticks or powder,
Grafts are retrieved from the Hippocratic crown and implantation is done on scar tissue.
It often takes 2 sessions to obtain a suitable result.
The hair follicle of an African type hair is curved.
This makes its extraction more complicated. It will therefore be privileged maxigrafts of 3/5 hairs rather than micrograft’s of 1 hair. Curly hairs naturally appears denser.
As a result, coverage will be easier to obtain and therefore fewer grafting sessions for the patient.
It will be necessary to ask the history of keloids.
Recommendations for the maintenance
of frizzy hair
Formulas containing high concentrations of anionic surfactants should be avoided to prevent the hair shaft from drying out significantly.
Conditioner should be applied after each shampoo on hair that is still damp.
It will reduce the friction between the hair fibres and reduce the force required to comb the hair.
When hair is very difficult to untangle the leave-in formulas can be used daily. Avoid placing conditioners on the scalp.
Their formulas contain many film-forming and occlusive products that will tend to block the follicle orifice pilosebaceous.
The accumulation of these residues can cause the appearance of folliculitis.
For easy combing with conditioners.
They promote the coating of the scales along the hair shaft.
Olive, argan, and avocado vegetable oils have a film-forming and sheating power while producing shine.
However it is recommended as for the conditioners not to apply them to the scalp in order not ti obstruct the pilosebaceous orifice.
Knowledge of the particularities of African hair and the hairdressing habits of people with frizzy hair allows us to understand the etiology of traumatic and chemical alopecia very often encountered in this population.
Existing treatments to treat these alopecias are not totally effective.
The immediate cessation of all practices and hair care responsible for the trauma observed.
The implementation of a medical treatment including a powerful anti-inflammatory sometimes coupled with an antibiotic in case of folliculitis must be discussed.
The prescription, from the first consultation, of a complementary prescription recommending the hair care to be carried out and the authorised hairstyles that will be recommended according to the particularities of each patient.