Causes of Hair Loss


Causes of Hair Loss:

  • Androgenic alopecia (Pattern hair loss)
  • Telogen effluvium (Non-pattern hair loss –  Generalized)
  • Hyper & Hypothyroidism
  • Hypoparathyroidism :Calcium levels
  • Hypopituitarism
  • Diabetes mellitus
  • Decreased Serum Ferritin levels : Anemia.
  • Low Serum Protein : Amino acids.
  • Deficiency of Vitamins A, C, E, Zinc, Selenium, Copper, etc.
  • Dieting, Stress, Anxiety, Lack of Sleep 

Additional cause:

  • Drugs
  • Weight loss
  • Acute blood loss
  • General anesthesia-Reversible (but may become chronic)
  • Post-partum

Common Scarring Alopecia:

  • Discoid lupus erythematosus
  • Lichen planopolaris
  • Sever fungal, viral, bactarial infections
  • Trauma or Burns

Androgenic alopecia or Pattern hair loss

Androgenic alopecia is by far the most common form of alopecia in men and women.

The development and occurrence of AGA depend on genetic predisposition and an interaction of endocrine factors.

How does pattern hair loss occurs( Pathogenesis)?

  • AGA involves both genetic and hormonal factors.

  • Different gene loci have been linked to the development of AG

After puberty, androgen triggers a series of events within theses genetically programmed hair follicles, predominately in fronto-parietal scalp area, that transform terminal to miniaturized follicles.

In AGA, hair cycle dynamic change. The time between shedding of hair and anagen regrowth become longer, leading to a reduction of present hair on the scalp.


The risk of AGA increases significantly with positive family history.
Inheritance is POLYGENIC (Kuester & Happel,1984)

The Expression of Insulin-like growth factor(IGF)-1, in dermal papilla, may play important role in the development of pattern baldness.

A gene locus on chromosome 12 (12q22-q23) may be responsible for male pattern baldness. More recent study shows that 17q21.31 may be locus for early onset AGA.

The CYP17 gene on chromosome 10q24.3 was held responsible for female pattern baldness.

Ellis shows there is no role of 5µ-reductase isoenzymes in the causation of male pattern baldness.

In balding scalp, higher expression of the androgen receptor gene was found which is located at band q12 in the X chromosome.

The involvement of the X chromosome in the development of AGA stresses the importance of the maternal line in inheritance.

Hormonal Factors

All enzymes can be located in the sebaceous gland and different parts of the hair follicle of the scalp skin. Therefore, pilosebaceous unit has the potential to mediate androgetic action without relying on elevated systemic levels or production of testosterone or DHT.

Increased level of AROMATASE (Detoxifying by removal of excess androgens) in females explain the difference in male and female patterns of balding and sparing of the frontal hairline.

Increases level of 5µ-androstane-3µ,17b-diolglucuronide and 5µ-reductase hyperactivity was found. Testosterone level is normal.
  • Male Pattern Baldness
  • More than 90% of hair loss problem in men are AGA.
  • Out of 10 males, 6 are suffering from MPB.
  • AGA usually starts at an early age and progresses slowly.
  • Thinning of hair can occur as early as the age of 12 or at any time later in life.
  • Most cases start between the ages of 15 and 25.
  • The clinical course is gradual.
  • Many men reach their maximum pattern by their forties.
  • Usually there is strong family history, but in about 12% cases, the family history is negative.

5µ-reductase plays a key role in AGA.Two 5µ-reductase isoenzymes are found in dermal papilla cells of beard and scalp follicles. In the balding scalp, a predominance of 5µ-reductase isotype 1 can be found.

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