Hair Loss (Part 1)

What is hair?

Hair is a protein filament made by keratin which grow from the follicles located in dermis. Surrounded by the hair follicles, hair bulb served as living cells to divide and grow the shaft. Hair divided into

1. Vellus hair – usually found throughout the body during prepubertal stage except lip, palm, sole and external genital area. It is short, thin, light color, unpigmented and barely noticeable.When during and after puberty, vellus hair will differentiate to terminal hair
2. Terminal hair – the hair found in this phase is much thicker, darker with greater extend in men than women.

Phase of hair growth ??

Hair growth approximately 1.2 cm per month and 15cm in a year.In fact, normal daily hair shedding is 50-100.

Divided into 3 phases :

1. Anagen phase ( growing phase ) – this phase generally is genetic determined. Around 85% of our scalp hair is in this stage but In androgenic alopecia, generally this stage has shorten and number of hair accounts in anagen phase maybe lesser than 85%.The longer the hair span staying in this phase , the longer the hair will grow. Physiologically this phase lasts 2-6 years
2. Catagen phase ( transition phase )- following the anagen phase ends, it enters catagen phase . At this stages , it lasts 1-2 weeks
3. Telogen phase ( resting  phase ) – lastly the hair entering to falling phase where the hair sheds and hair follicles remain dormant 2-4 months before the cycles will restart from anagen phase

What causes hair loss?

Hair loss have became a common issues among men and women. Estimated 40% men will noticeable hair loss at the age of 35, and visible hair thinning in women at age of 40.

1. Genetic predisposition – Hair loss also known as alopecia. If inherited ,its related to X-linked recessive androgen receptor gene and known as androgenic alopecia.Male pattern hair loss accounts 95% of man hair loss characterized by receding hairline or hair loss on the top of scalp. A similar phenomena in women known as female pattern hair loss.It is caused by the conversion of testosterone hormone into DHT( dihydrotestesteone) by the enzyme 5-alpha reductase. Due to the inherited , the high level of follicle sensitivity is more susceptible to DHT. It affects more than 50% of men above 50years old. If left untreated, miniaturization of hairs and baldness may occurs as early at the age of 30.In female pattern hair loss characterized with generalized hair thinning. Hair plays a important rule for physical appearance -the crown of beauty.Hair thinning may give the perception of pre-mature aging which affects the quality of life  and embarrassment . Mechanism of DHT and Stages of androgenic  as below:

2. Hormonal imbalances – PCOS ( polycyclic ovarian syndrome )  is an endocrine disorder generally affecting 5-10% women in reproductive age. The exact causes are unknown.It maybe due to a combination of genetic and environmental factors. Risk factor include insulin resistance and obesity.Androgen commonly believe is the culprit. To diagnose as PCOS – there are some criteria needs to be fulfilled -2 out of 3

1. Oligoovulation and /or an ovulation
2. excessive androgen activity
3. Polycystic ovaries by ultrasound examination ( sign of “ A String of Pearls”)

Common signs and symptoms included

– Menstrual disorder – oligomenorhea or ammenorhae, dysmenorrhea
-Infertility
-Stress
-Depression
-High level of androgen – hirsutism( male pattern hair growth), acne, oily skin, androgenic alopecia
-Metablc syndrome – weight gain with central obesity and insulin resistance, abnormal skin discoloration,

3. Medical illness – hormones are important to regulate normal function of cells. Thyroid hormone such as thyroxine (T4) and triiodothyronine (T3) directly regulate the hair  growth cycles .A severe and prolonged hyperthyroid or hypothyroid may cause hair loss. Don’t worry, its not permanent.A successful treatment may reverse hair loss.The pattern of hair loss usually is diffuse involving whole scalp. Most people with hyper- or hypothyoird may have autoimmune disease. Its advisable to get further investigate .After started on the treatment,a significant improve can be seen in the first month.Some may experience parodoxical hair loss, leading to withdrawal of the treatment,which in turn worsen the condition.

4. Telogen effluvium also known as diffuse hair loss.Probably second most common cause of hair loss.Characterized by the early re-entry hair follicles to telogen phase which increase the resting hair follicles from 15% to 25% and significantly prolonged telogen phase.This shedding may lasts up t0 6 months. Chronic TE is shedding longer than 6 months.Hair loss in TE will never be bald and noticeable thin in severe cases.Clinically in females, can be confused with female pattern hair loss.Causes as below :

1. Post partum
2. Weight loss
3. Dietary deficiencies – low zinc, vit B6 and B12 , iron

D.Stress

1. Surgical operation
2. Acute infection
3. Oversea traveling with jet lag
4. Accident

Classical of TE often happen in women after delivery also know as postpartum alopecia.During the pregnancy, the hair follicles are fully supported by the estrogen and progesterone.After delivery,a sudden change of hormones level give an insult to the follicles and shutting off whereby the shedding may starts as early at 3 months after delivery and continues to a year.

Dietary deficiencies frequently occurs in vegetarian. Red meats is a key source of high in iron and when they lack of the intake of meats TE can occurs.When dietary deficiencies is suspected, supplements are highly recommended.

To Be Continued…….

Written by
Dr Michelle Lai Wai See
Premier Clinic